x86/lguest: Remove lguest support

Lguest seems to be rather unused these days. It has seen only patches
ensuring it still builds the last two years and its official state is
"Odd Fixes".

Remove it in order to be able to clean up the paravirt code.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: boris.ostrovsky@oracle.com
Cc: lguest@lists.ozlabs.org
Cc: rusty@rustcorp.com.au
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20170816173157.8633-3-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

12 files changed, 0 insertions, 4777 deletions

diff --git a/drivers/lguest/Kconfig b/drivers/lguest/Kconfig
deleted file mode 100644
index 169172d2ba05..000000000000
--- a/drivers/lguest/Kconfig
+++ /dev/null
@@ -1,13 +0,0 @@
-config LGUEST
-	tristate "Linux hypervisor example code"
-	depends on X86_32 && EVENTFD && TTY && PCI_DIRECT
-	select HVC_DRIVER
-	---help---
-	  This is a very simple module which allows you to run
-	  multiple instances of the same Linux kernel, using the
-	  "lguest" command found in the tools/lguest directory.
-
-	  Note that "lguest" is pronounced to rhyme with "fell quest",
-	  not "rustyvisor". See tools/lguest/lguest.txt.
-
-	  If unsure, say N.  If curious, say M.  If masochistic, say Y.
diff --git a/drivers/lguest/Makefile b/drivers/lguest/Makefile
deleted file mode 100644
index 16f52ee73994..000000000000
--- a/drivers/lguest/Makefile
+++ /dev/null
@@ -1,26 +0,0 @@
-# Host requires the other files, which can be a module.
-obj-$(CONFIG_LGUEST)	+= lg.o
-lg-y = core.o hypercalls.o page_tables.o interrupts_and_traps.o \
-	segments.o lguest_user.o
-
-lg-$(CONFIG_X86_32) += x86/switcher_32.o x86/core.o
-
-Preparation Preparation!: PREFIX=P
-Guest: PREFIX=G
-Drivers: PREFIX=D
-Launcher: PREFIX=L
-Host: PREFIX=H
-Switcher: PREFIX=S
-Mastery: PREFIX=M
-Beer:
-	@for f in Preparation Guest Drivers Launcher Host Switcher Mastery; do echo "{==- $$f -==}"; make -s $$f; done; echo "{==-==}"
-Preparation Preparation! Guest Drivers Launcher Host Switcher Mastery:
-	@sh ../../tools/lguest/extract $(PREFIX) `find ../../* -name '*.[chS]' -wholename '*lguest*'`
-Puppy:
-	@clear
-	@printf "      __  \n (___()'\`;\n /,    /\`\n \\\\\\\"--\\\\\\   \n"
-	@sleep 2; clear; printf "\n\n   Sit!\n\n"; sleep 1; clear
-	@printf "    __    \n   ()'\`;  \n   /\\|\` \n  /  |  \n(/_)_|_   \n"
-	@sleep 2; clear; printf "\n\n  Stand!\n\n"; sleep 1; clear
-	@printf "    __    \n   ()'\`;  \n   /\\|\` \n  /._.= \n /| /     \n(_\_)_    \n"
-	@sleep 2; clear; printf "\n\n  Good puppy!\n\n"; sleep 1; clear
diff --git a/drivers/lguest/README b/drivers/lguest/README
deleted file mode 100644
index b7db39a64c66..000000000000
--- a/drivers/lguest/README
+++ /dev/null
@@ -1,47 +0,0 @@
-Welcome, friend reader, to lguest.
-
-Lguest is an adventure, with you, the reader, as Hero.  I can't think of many
-5000-line projects which offer both such capability and glimpses of future
-potential; it is an exciting time to be delving into the source!
-
-But be warned; this is an arduous journey of several hours or more!  And as we
-know, all true Heroes are driven by a Noble Goal.  Thus I offer a Beer (or
-equivalent) to anyone I meet who has completed this documentation.
-
-So get comfortable and keep your wits about you (both quick and humorous).
-Along your way to the Noble Goal, you will also gain masterly insight into
-lguest, and hypervisors and x86 virtualization in general.
-
-Our Quest is in seven parts: (best read with C highlighting turned on)
-
-I) Preparation
-	- In which our potential hero is flown quickly over the landscape for a
-	  taste of its scope.  Suitable for the armchair coders and other such
-	  persons of faint constitution.
-
-II) Guest
-	- Where we encounter the first tantalising wisps of code, and come to
-	  understand the details of the life of a Guest kernel.
-
-III) Drivers
-	- Whereby the Guest finds its voice and become useful, and our
-	  understanding of the Guest is completed.
-
-IV) Launcher
-	- Where we trace back to the creation of the Guest, and thus begin our
-	  understanding of the Host.
-
-V) Host
-	- Where we master the Host code, through a long and tortuous journey.
-	  Indeed, it is here that our hero is tested in the Bit of Despair.
-
-VI) Switcher
-	- Where our understanding of the intertwined nature of Guests and Hosts
-	  is completed.
-
-VII) Mastery
-	- Where our fully fledged hero grapples with the Great Question:
-	  "What next?"
-
-make Preparation!
-Rusty Russell.
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
deleted file mode 100644
index 395ed1961dbf..000000000000
--- a/drivers/lguest/core.c
+++ /dev/null
@@ -1,398 +0,0 @@
-/*P:400
- * This contains run_guest() which actually calls into the Host<->Guest
- * Switcher and analyzes the return, such as determining if the Guest wants the
- * Host to do something.  This file also contains useful helper routines.
-:*/
-#include <linux/module.h>
-#include <linux/stringify.h>
-#include <linux/stddef.h>
-#include <linux/io.h>
-#include <linux/mm.h>
-#include <linux/sched/signal.h>
-#include <linux/vmalloc.h>
-#include <linux/cpu.h>
-#include <linux/freezer.h>
-#include <linux/highmem.h>
-#include <linux/slab.h>
-#include <asm/paravirt.h>
-#include <asm/pgtable.h>
-#include <linux/uaccess.h>
-#include <asm/poll.h>
-#include <asm/asm-offsets.h>
-#include "lg.h"
-
-unsigned long switcher_addr;
-struct page **lg_switcher_pages;
-static struct vm_struct *switcher_text_vma;
-static struct vm_struct *switcher_stacks_vma;
-
-/* This One Big lock protects all inter-guest data structures. */
-DEFINE_MUTEX(lguest_lock);
-
-/*H:010
- * We need to set up the Switcher at a high virtual address.  Remember the
- * Switcher is a few hundred bytes of assembler code which actually changes the
- * CPU to run the Guest, and then changes back to the Host when a trap or
- * interrupt happens.
- *
- * The Switcher code must be at the same virtual address in the Guest as the
- * Host since it will be running as the switchover occurs.
- *
- * Trying to map memory at a particular address is an unusual thing to do, so
- * it's not a simple one-liner.
- */
-static __init int map_switcher(void)
-{
-	int i, err;
-
-	/*
-	 * Map the Switcher in to high memory.
-	 *
-	 * It turns out that if we choose the address 0xFFC00000 (4MB under the
-	 * top virtual address), it makes setting up the page tables really
-	 * easy.
-	 */
-
-	/* We assume Switcher text fits into a single page. */
-	if (end_switcher_text - start_switcher_text > PAGE_SIZE) {
-		printk(KERN_ERR "lguest: switcher text too large (%zu)\n",
-		       end_switcher_text - start_switcher_text);
-		return -EINVAL;
-	}
-
-	/*
-	 * We allocate an array of struct page pointers.  map_vm_area() wants
-	 * this, rather than just an array of pages.
-	 */
-	lg_switcher_pages = kmalloc(sizeof(lg_switcher_pages[0])
-				    * TOTAL_SWITCHER_PAGES,
-				    GFP_KERNEL);
-	if (!lg_switcher_pages) {
-		err = -ENOMEM;
-		goto out;
-	}
-
-	/*
-	 * Now we actually allocate the pages.  The Guest will see these pages,
-	 * so we make sure they're zeroed.
-	 */
-	for (i = 0; i < TOTAL_SWITCHER_PAGES; i++) {
-		lg_switcher_pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
-		if (!lg_switcher_pages[i]) {
-			err = -ENOMEM;
-			goto free_some_pages;
-		}
-	}
-
-	/*
-	 * Copy in the compiled-in Switcher code (from x86/switcher_32.S).
-	 * It goes in the first page, which we map in momentarily.
-	 */
-	memcpy(kmap(lg_switcher_pages[0]), start_switcher_text,
-	       end_switcher_text - start_switcher_text);
-	kunmap(lg_switcher_pages[0]);
-
-	/*
-	 * We place the Switcher underneath the fixmap area, which is the
-	 * highest virtual address we can get.  This is important, since we
-	 * tell the Guest it can't access this memory, so we want its ceiling
-	 * as high as possible.
-	 */
-	switcher_addr = FIXADDR_START - TOTAL_SWITCHER_PAGES*PAGE_SIZE;
-
-	/*
-	 * Now we reserve the "virtual memory area"s we want.  We might
-	 * not get them in theory, but in practice it's worked so far.
-	 *
-	 * We want the switcher text to be read-only and executable, and
-	 * the stacks to be read-write and non-executable.
-	 */
-	switcher_text_vma = __get_vm_area(PAGE_SIZE, VM_ALLOC|VM_NO_GUARD,
-					  switcher_addr,
-					  switcher_addr + PAGE_SIZE);
-
-	if (!switcher_text_vma) {
-		err = -ENOMEM;
-		printk("lguest: could not map switcher pages high\n");
-		goto free_pages;
-	}
-
-	switcher_stacks_vma = __get_vm_area(SWITCHER_STACK_PAGES * PAGE_SIZE,
-					    VM_ALLOC|VM_NO_GUARD,
-					    switcher_addr + PAGE_SIZE,
-					    switcher_addr + TOTAL_SWITCHER_PAGES * PAGE_SIZE);
-	if (!switcher_stacks_vma) {
-		err = -ENOMEM;
-		printk("lguest: could not map switcher pages high\n");
-		goto free_text_vma;
-	}
-
-	/*
-	 * This code actually sets up the pages we've allocated to appear at
-	 * switcher_addr.  map_vm_area() takes the vma we allocated above, the
-	 * kind of pages we're mapping (kernel text pages and kernel writable
-	 * pages respectively), and a pointer to our array of struct pages.
-	 */
-	err = map_vm_area(switcher_text_vma, PAGE_KERNEL_RX, lg_switcher_pages);
-	if (err) {
-		printk("lguest: text map_vm_area failed: %i\n", err);
-		goto free_vmas;
-	}
-
-	err = map_vm_area(switcher_stacks_vma, PAGE_KERNEL,
-			  lg_switcher_pages + SWITCHER_TEXT_PAGES);
-	if (err) {
-		printk("lguest: stacks map_vm_area failed: %i\n", err);
-		goto free_vmas;
-	}
-
-	/*
-	 * Now the Switcher is mapped at the right address, we can't fail!
-	 */
-	printk(KERN_INFO "lguest: mapped switcher at %p\n",
-	       switcher_text_vma->addr);
-	/* And we succeeded... */
-	return 0;
-
-free_vmas:
-	/* Undoes map_vm_area and __get_vm_area */
-	vunmap(switcher_stacks_vma->addr);
-free_text_vma:
-	vunmap(switcher_text_vma->addr);
-free_pages:
-	i = TOTAL_SWITCHER_PAGES;
-free_some_pages:
-	for (--i; i >= 0; i--)
-		__free_pages(lg_switcher_pages[i], 0);
-	kfree(lg_switcher_pages);
-out:
-	return err;
-}
-/*:*/
-
-/* Cleaning up the mapping when the module is unloaded is almost... too easy. */
-static void unmap_switcher(void)
-{
-	unsigned int i;
-
-	/* vunmap() undoes *both* map_vm_area() and __get_vm_area(). */
-	vunmap(switcher_text_vma->addr);
-	vunmap(switcher_stacks_vma->addr);
-	/* Now we just need to free the pages we copied the switcher into */
-	for (i = 0; i < TOTAL_SWITCHER_PAGES; i++)
-		__free_pages(lg_switcher_pages[i], 0);
-	kfree(lg_switcher_pages);
-}
-
-/*H:032
- * Dealing With Guest Memory.
- *
- * Before we go too much further into the Host, we need to grok the routines
- * we use to deal with Guest memory.
- *
- * When the Guest gives us (what it thinks is) a physical address, we can use
- * the normal copy_from_user() & copy_to_user() on the corresponding place in
- * the memory region allocated by the Launcher.
- *
- * But we can't trust the Guest: it might be trying to access the Launcher
- * code.  We have to check that the range is below the pfn_limit the Launcher
- * gave us.  We have to make sure that addr + len doesn't give us a false
- * positive by overflowing, too.
- */
-bool lguest_address_ok(const struct lguest *lg,
-		       unsigned long addr, unsigned long len)
-{
-	return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr);
-}
-
-/*
- * This routine copies memory from the Guest.  Here we can see how useful the
- * kill_lguest() routine we met in the Launcher can be: we return a random
- * value (all zeroes) instead of needing to return an error.
- */
-void __lgread(struct lg_cpu *cpu, void *b, unsigned long addr, unsigned bytes)
-{
-	if (!lguest_address_ok(cpu->lg, addr, bytes)
-	    || copy_from_user(b, cpu->lg->mem_base + addr, bytes) != 0) {
-		/* copy_from_user should do this, but as we rely on it... */
-		memset(b, 0, bytes);
-		kill_guest(cpu, "bad read address %#lx len %u", addr, bytes);
-	}
-}
-
-/* This is the write (copy into Guest) version. */
-void __lgwrite(struct lg_cpu *cpu, unsigned long addr, const void *b,
-	       unsigned bytes)
-{
-	if (!lguest_address_ok(cpu->lg, addr, bytes)
-	    || copy_to_user(cpu->lg->mem_base + addr, b, bytes) != 0)
-		kill_guest(cpu, "bad write address %#lx len %u", addr, bytes);
-}
-/*:*/
-
-/*H:030
- * Let's jump straight to the the main loop which runs the Guest.
- * Remember, this is called by the Launcher reading /dev/lguest, and we keep
- * going around and around until something interesting happens.
- */
-int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
-{
-	/* If the launcher asked for a register with LHREQ_GETREG */
-	if (cpu->reg_read) {
-		if (put_user(*cpu->reg_read, user))
-			return -EFAULT;
-		cpu->reg_read = NULL;
-		return sizeof(*cpu->reg_read);
-	}
-
-	/* We stop running once the Guest is dead. */
-	while (!cpu->lg->dead) {
-		unsigned int irq;
-		bool more;
-
-		/* First we run any hypercalls the Guest wants done. */
-		if (cpu->hcall)
-			do_hypercalls(cpu);
-
-		/* Do we have to tell the Launcher about a trap? */
-		if (cpu->pending.trap) {
-			if (copy_to_user(user, &cpu->pending,
-					 sizeof(cpu->pending)))
-				return -EFAULT;
-			return sizeof(cpu->pending);
-		}
-
-		/*
-		 * All long-lived kernel loops need to check with this horrible
-		 * thing called the freezer.  If the Host is trying to suspend,
-		 * it stops us.
-		 */
-		try_to_freeze();
-
-		/* Check for signals */
-		if (signal_pending(current))
-			return -ERESTARTSYS;
-
-		/*
-		 * Check if there are any interrupts which can be delivered now:
-		 * if so, this sets up the hander to be executed when we next
-		 * run the Guest.
-		 */
-		irq = interrupt_pending(cpu, &more);
-		if (irq < LGUEST_IRQS)
-			try_deliver_interrupt(cpu, irq, more);
-
-		/*
-		 * Just make absolutely sure the Guest is still alive.  One of
-		 * those hypercalls could have been fatal, for example.
-		 */
-		if (cpu->lg->dead)
-			break;
-
-		/*
-		 * If the Guest asked to be stopped, we sleep.  The Guest's
-		 * clock timer will wake us.
-		 */
-		if (cpu->halted) {
-			set_current_state(TASK_INTERRUPTIBLE);
-			/*
-			 * Just before we sleep, make sure no interrupt snuck in
-			 * which we should be doing.
-			 */
-			if (interrupt_pending(cpu, &more) < LGUEST_IRQS)
-				set_current_state(TASK_RUNNING);
-			else
-				schedule();
-			continue;
-		}
-
-		/*
-		 * OK, now we're ready to jump into the Guest.  First we put up
-		 * the "Do Not Disturb" sign:
-		 */
-		local_irq_disable();
-
-		/* Actually run the Guest until something happens. */
-		lguest_arch_run_guest(cpu);
-
-		/* Now we're ready to be interrupted or moved to other CPUs */
-		local_irq_enable();
-
-		/* Now we deal with whatever happened to the Guest. */
-		lguest_arch_handle_trap(cpu);
-	}
-
-	/* Special case: Guest is 'dead' but wants a reboot. */
-	if (cpu->lg->dead == ERR_PTR(-ERESTART))
-		return -ERESTART;
-
-	/* The Guest is dead => "No such file or directory" */
-	return -ENOENT;
-}
-
-/*H:000
- * Welcome to the Host!
- *
- * By this point your brain has been tickled by the Guest code and numbed by
- * the Launcher code; prepare for it to be stretched by the Host code.  This is
- * the heart.  Let's begin at the initialization routine for the Host's lg
- * module.
- */
-static int __init init(void)
-{
-	int err;
-
-	/* Lguest can't run under Xen, VMI or itself.  It does Tricky Stuff. */
-	if (get_kernel_rpl() != 0) {
-		printk("lguest is afraid of being a guest\n");
-		return -EPERM;
-	}
-
-	/* First we put the Switcher up in very high virtual memory. */
-	err = map_switcher();
-	if (err)
-		goto out;
-
-	/* We might need to reserve an interrupt vector. */
-	err = init_interrupts();
-	if (err)
-		goto unmap;
-
-	/* /dev/lguest needs to be registered. */
-	err = lguest_device_init();
-	if (err)
-		goto free_interrupts;
-
-	/* Finally we do some architecture-specific setup. */
-	lguest_arch_host_init();
-
-	/* All good! */
-	return 0;
-
-free_interrupts:
-	free_interrupts();
-unmap:
-	unmap_switcher();
-out:
-	return err;
-}
-
-/* Cleaning up is just the same code, backwards.  With a little French. */
-static void __exit fini(void)
-{
-	lguest_device_remove();
-	free_interrupts();
-	unmap_switcher();
-
-	lguest_arch_host_fini();
-}
-/*:*/
-
-/*
- * The Host side of lguest can be a module.  This is a nice way for people to
- * play with it.
- */
-module_init(init);
-module_exit(fini);
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
deleted file mode 100644
index 601f81c04873..000000000000
--- a/drivers/lguest/hypercalls.c
+++ /dev/null
@@ -1,304 +0,0 @@
-/*P:500
- * Just as userspace programs request kernel operations through a system
- * call, the Guest requests Host operations through a "hypercall".  You might
- * notice this nomenclature doesn't really follow any logic, but the name has
- * been around for long enough that we're stuck with it.  As you'd expect, this
- * code is basically a one big switch statement.
-:*/
-
-/*  Copyright (C) 2006 Rusty Russell IBM Corporation
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
-*/
-#include <linux/uaccess.h>
-#include <linux/syscalls.h>
-#include <linux/mm.h>
-#include <linux/ktime.h>
-#include <asm/page.h>
-#include <asm/pgtable.h>
-#include "lg.h"
-
-/*H:120
- * This is the core hypercall routine: where the Guest gets what it wants.
- * Or gets killed.  Or, in the case of LHCALL_SHUTDOWN, both.
- */
-static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
-{
-	switch (args->arg0) {
-	case LHCALL_FLUSH_ASYNC:
-		/*
-		 * This call does nothing, except by breaking out of the Guest
-		 * it makes us process all the asynchronous hypercalls.
-		 */
-		break;
-	case LHCALL_SEND_INTERRUPTS:
-		/*
-		 * This call does nothing too, but by breaking out of the Guest
-		 * it makes us process any pending interrupts.
-		 */
-		break;
-	case LHCALL_LGUEST_INIT:
-		/*
-		 * You can't get here unless you're already initialized.  Don't
-		 * do that.
-		 */
-		kill_guest(cpu, "already have lguest_data");
-		break;
-	case LHCALL_SHUTDOWN: {
-		char msg[128];
-		/*
-		 * Shutdown is such a trivial hypercall that we do it in five
-		 * lines right here.
-		 *
-		 * If the lgread fails, it will call kill_guest() itself; the
-		 * kill_guest() with the message will be ignored.
-		 */
-		__lgread(cpu, msg, args->arg1, sizeof(msg));
-		msg[sizeof(msg)-1] = '\0';
-		kill_guest(cpu, "CRASH: %s", msg);
-		if (args->arg2 == LGUEST_SHUTDOWN_RESTART)
-			cpu->lg->dead = ERR_PTR(-ERESTART);
-		break;
-	}
-	case LHCALL_FLUSH_TLB:
-		/* FLUSH_TLB comes in two flavors, depending on the argument: */
-		if (args->arg1)
-			guest_pagetable_clear_all(cpu);
-		else
-			guest_pagetable_flush_user(cpu);
-		break;
-
-	/*
-	 * All these calls simply pass the arguments through to the right
-	 * routines.
-	 */
-	case LHCALL_NEW_PGTABLE:
-		guest_new_pagetable(cpu, args->arg1);
-		break;
-	case LHCALL_SET_STACK:
-		guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);
-		break;
-	case LHCALL_SET_PTE:
-#ifdef CONFIG_X86_PAE
-		guest_set_pte(cpu, args->arg1, args->arg2,
-				__pte(args->arg3 | (u64)args->arg4 << 32));
-#else
-		guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3));
-#endif
-		break;
-	case LHCALL_SET_PGD:
-		guest_set_pgd(cpu->lg, args->arg1, args->arg2);
-		break;
-#ifdef CONFIG_X86_PAE
-	case LHCALL_SET_PMD:
-		guest_set_pmd(cpu->lg, args->arg1, args->arg2);
-		break;
-#endif
-	case LHCALL_SET_CLOCKEVENT:
-		guest_set_clockevent(cpu, args->arg1);
-		break;
-	case LHCALL_HALT:
-		/* Similarly, this sets the halted flag for run_guest(). */
-		cpu->halted = 1;
-		break;
-	default:
-		/* It should be an architecture-specific hypercall. */
-		if (lguest_arch_do_hcall(cpu, args))
-			kill_guest(cpu, "Bad hypercall %li\n", args->arg0);
-	}
-}
-
-/*H:124
- * Asynchronous hypercalls are easy: we just look in the array in the
- * Guest's "struct lguest_data" to see if any new ones are marked "ready".
- *
- * We are careful to do these in order: obviously we respect the order the
- * Guest put them in the ring, but we also promise the Guest that they will
- * happen before any normal hypercall (which is why we check this before
- * checking for a normal hcall).
- */
-static void do_async_hcalls(struct lg_cpu *cpu)
-{
-	unsigned int i;
-	u8 st[LHCALL_RING_SIZE];
-
-	/* For simplicity, we copy the entire call status array in at once. */
-	if (copy_from_user(&st, &cpu->lg->lguest_data->hcall_status, sizeof(st)))
-		return;
-
-	/* We process "struct lguest_data"s hcalls[] ring once. */
-	for (i = 0; i < ARRAY_SIZE(st); i++) {
-		struct hcall_args args;
-		/*
-		 * We remember where we were up to from last time.  This makes
-		 * sure that the hypercalls are done in the order the Guest
-		 * places them in the ring.
-		 */
-		unsigned int n = cpu->next_hcall;
-
-		/* 0xFF means there's no call here (yet). */
-		if (st[n] == 0xFF)
-			break;
-
-		/*
-		 * OK, we have hypercall.  Increment the "next_hcall" cursor,
-		 * and wrap back to 0 if we reach the end.
-		 */
-		if (++cpu->next_hcall == LHCALL_RING_SIZE)
-			cpu->next_hcall = 0;
-
-		/*
-		 * Copy the hypercall arguments into a local copy of the
-		 * hcall_args struct.
-		 */
-		if (copy_from_user(&args, &cpu->lg->lguest_data->hcalls[n],
-				   sizeof(struct hcall_args))) {
-			kill_guest(cpu, "Fetching async hypercalls");
-			break;
-		}
-
-		/* Do the hypercall, same as a normal one. */
-		do_hcall(cpu, &args);
-
-		/* Mark the hypercall done. */
-		if (put_user(0xFF, &cpu->lg->lguest_data->hcall_status[n])) {
-			kill_guest(cpu, "Writing result for async hypercall");
-			break;
-		}
-
-		/*
-		 * Stop doing hypercalls if they want to notify the Launcher:
-		 * it needs to service this first.
-		 */
-		if (cpu->pending.trap)
-			break;
-	}
-}
-
-/*
- * Last of all, we look at what happens first of all.  The very first time the
- * Guest makes a hypercall, we end up here to set things up:
- */
-static void initialize(struct lg_cpu *cpu)
-{
-	/*
-	 * You can't do anything until you're initialized.  The Guest knows the
-	 * rules, so we're unforgiving here.
-	 */
-	if (cpu->hcall->arg0 != LHCALL_LGUEST_INIT) {
-		kill_guest(cpu, "hypercall %li before INIT", cpu->hcall->arg0);
-		return;
-	}
-
-	if (lguest_arch_init_hypercalls(cpu))
-		kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
-
-	/*
-	 * The Guest tells us where we're not to deliver interrupts by putting
-	 * the instruction address into "struct lguest_data".
-	 */
-	if (get_user(cpu->lg->noirq_iret, &cpu->lg->lguest_data->noirq_iret))
-		kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
-
-	/*
-	 * We write the current time into the Guest's data page once so it can
-	 * set its clock.
-	 */
-	write_timestamp(cpu);
-
-	/* page_tables.c will also do some setup. */
-	page_table_guest_data_init(cpu);
-
-	/*
-	 * This is the one case where the above accesses might have been the
-	 * first write to a Guest page.  This may have caused a copy-on-write
-	 * fault, but the old page might be (read-only) in the Guest
-	 * pagetable.
-	 */
-	guest_pagetable_clear_all(cpu);
-}
-/*:*/
-
-/*M:013
- * If a Guest reads from a page (so creates a mapping) that it has never
- * written to, and then the Launcher writes to it (ie. the output of a virtual
- * device), the Guest will still see the old page.  In practice, this never
- * happens: why would the Guest read a page which it has never written to?  But
- * a similar scenario might one day bite us, so it's worth mentioning.
- *
- * Note that if we used a shared anonymous mapping in the Launcher instead of
- * mapping /dev/zero private, we wouldn't worry about cop-on-write.  And we
- * need that to switch the Launcher to processes (away from threads) anyway.
-:*/
-
-/*H:100
- * Hypercalls
- *
- * Remember from the Guest, hypercalls come in two flavors: normal and
- * asynchronous.  This file handles both of types.
- */
-void do_hypercalls(struct lg_cpu *cpu)
-{
-	/* Not initialized yet?  This hypercall must do it. */
-	if (unlikely(!cpu->lg->lguest_data)) {
-		/* Set up the "struct lguest_data" */
-		initialize(cpu);
-		/* Hcall is done. */
-		cpu->hcall = NULL;
-		return;
-	}
-
-	/*
-	 * The Guest has initialized.
-	 *
-	 * Look in the hypercall ring for the async hypercalls:
-	 */
-	do_async_hcalls(cpu);
-
-	/*
-	 * If we stopped reading the hypercall ring because the Guest did a
-	 * NOTIFY to the Launcher, we want to return now.  Otherwise we do
-	 * the hypercall.
-	 */
-	if (!cpu->pending.trap) {
-		do_hcall(cpu, cpu->hcall);
-		/*
-		 * Tricky point: we reset the hcall pointer to mark the
-		 * hypercall as "done".  We use the hcall pointer rather than
-		 * the trap number to indicate a hypercall is pending.
-		 * Normally it doesn't matter: the Guest will run again and
-		 * update the trap number before we come back here.
-		 *
-		 * However, if we are signalled or the Guest sends I/O to the
-		 * Launcher, the run_guest() loop will exit without running the
-		 * Guest.  When it comes back it would try to re-run the
-		 * hypercall.  Finding that bug sucked.
-		 */
-		cpu->hcall = NULL;
-	}
-}
-
-/*
- * This routine supplies the Guest with time: it's used for wallclock time at
- * initial boot and as a rough time source if the TSC isn't available.
- */
-void write_timestamp(struct lg_cpu *cpu)
-{
-	struct timespec now;
-	ktime_get_real_ts(&now);
-	if (copy_to_user(&cpu->lg->lguest_data->time,
-			 &now, sizeof(struct timespec)))
-		kill_guest(cpu, "Writing timestamp");
-}
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
deleted file mode 100644
index 67392b6ab845..000000000000
--- a/drivers/lguest/interrupts_and_traps.c
+++ /dev/null
@@ -1,706 +0,0 @@
-/*P:800
- * Interrupts (traps) are complicated enough to earn their own file.
- * There are three classes of interrupts:
- *
- * 1) Real hardware interrupts which occur while we're running the Guest,
- * 2) Interrupts for virtual devices attached to the Guest, and
- * 3) Traps and faults from the Guest.
- *
- * Real hardware interrupts must be delivered to the Host, not the Guest.
- * Virtual interrupts must be delivered to the Guest, but we make them look
- * just like real hardware would deliver them.  Traps from the Guest can be set
- * up to go directly back into the Guest, but sometimes the Host wants to see
- * them first, so we also have a way of "reflecting" them into the Guest as if
- * they had been delivered to it directly.
-:*/
-#include <linux/uaccess.h>
-#include <linux/interrupt.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include "lg.h"
-
-/* Allow Guests to use a non-128 (ie. non-Linux) syscall trap. */
-static unsigned int syscall_vector = IA32_SYSCALL_VECTOR;
-module_param(syscall_vector, uint, 0444);
-
-/* The address of the interrupt handler is split into two bits: */
-static unsigned long idt_address(u32 lo, u32 hi)
-{
-	return (lo & 0x0000FFFF) | (hi & 0xFFFF0000);
-}
-
-/*
- * The "type" of the interrupt handler is a 4 bit field: we only support a
- * couple of types.
- */
-static int idt_type(u32 lo, u32 hi)
-{
-	return (hi >> 8) & 0xF;
-}
-
-/* An IDT entry can't be used unless the "present" bit is set. */
-static bool idt_present(u32 lo, u32 hi)
-{
-	return (hi & 0x8000);
-}
-
-/*
- * We need a helper to "push" a value onto the Guest's stack, since that's a
- * big part of what delivering an interrupt does.
- */
-static void push_guest_stack(struct lg_cpu *cpu, unsigned long *gstack, u32 val)
-{
-	/* Stack grows upwards: move stack then write value. */
-	*gstack -= 4;
-	lgwrite(cpu, *gstack, u32, val);
-}
-
-/*H:210
- * The push_guest_interrupt_stack() routine saves Guest state on the stack for
- * an interrupt or trap.  The mechanics of delivering traps and interrupts to
- * the Guest are the same, except some traps have an "error code" which gets
- * pushed onto the stack as well: the caller tells us if this is one.
- *
- * We set up the stack just like the CPU does for a real interrupt, so it's
- * identical for the Guest (and the standard "iret" instruction will undo
- * it).
- */
-static void push_guest_interrupt_stack(struct lg_cpu *cpu, bool has_err)
-{
-	unsigned long gstack, origstack;
-	u32 eflags, ss, irq_enable;
-	unsigned long virtstack;
-
-	/*
-	 * There are two cases for interrupts: one where the Guest is already
-	 * in the kernel, and a more complex one where the Guest is in
-	 * userspace.  We check the privilege level to find out.
-	 */
-	if ((cpu->regs->ss&0x3) != GUEST_PL) {
-		/*
-		 * The Guest told us their kernel stack with the SET_STACK
-		 * hypercall: both the virtual address and the segment.
-		 */
-		virtstack = cpu->esp1;
-		ss = cpu->ss1;
-
-		origstack = gstack = guest_pa(cpu, virtstack);
-		/*
-		 * We push the old stack segment and pointer onto the new
-		 * stack: when the Guest does an "iret" back from the interrupt
-		 * handler the CPU will notice they're dropping privilege
-		 * levels and expect these here.
-		 */
-		push_guest_stack(cpu, &gstack, cpu->regs->ss);
-		push_guest_stack(cpu, &gstack, cpu->regs->esp);
-	} else {
-		/* We're staying on the same Guest (kernel) stack. */
-		virtstack = cpu->regs->esp;
-		ss = cpu->regs->ss;
-
-		origstack = gstack = guest_pa(cpu, virtstack);
-	}
-
-	/*
-	 * Remember that we never let the Guest actually disable interrupts, so
-	 * the "Interrupt Flag" bit is always set.  We copy that bit from the
-	 * Guest's "irq_enabled" field into the eflags word: we saw the Guest
-	 * copy it back in "lguest_iret".
-	 */
-	eflags = cpu->regs->eflags;
-	if (get_user(irq_enable, &cpu->lg->lguest_data->irq_enabled) == 0
-	    && !(irq_enable & X86_EFLAGS_IF))
-		eflags &= ~X86_EFLAGS_IF;
-
-	/*
-	 * An interrupt is expected to push three things on the stack: the old
-	 * "eflags" word, the old code segment, and the old instruction
-	 * pointer.
-	 */
-	push_guest_stack(cpu, &gstack, eflags);
-	push_guest_stack(cpu, &gstack, cpu->regs->cs);
-	push_guest_stack(cpu, &gstack, cpu->regs->eip);
-
-	/* For the six traps which supply an error code, we push that, too. */
-	if (has_err)
-		push_guest_stack(cpu, &gstack, cpu->regs->errcode);
-
-	/* Adjust the stack pointer and stack segment. */
-	cpu->regs->ss = ss;
-	cpu->regs->esp = virtstack + (gstack - origstack);
-}
-
-/*
- * This actually makes the Guest start executing the given interrupt/trap
- * handler.
- *
- * "lo" and "hi" are the two parts of the Interrupt Descriptor Table for this
- * interrupt or trap.  It's split into two parts for traditional reasons: gcc
- * on i386 used to be frightened by 64 bit numbers.
- */
-static void guest_run_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi)
-{
-	/* If we're already in the kernel, we don't change stacks. */
-	if ((cpu->regs->ss&0x3) != GUEST_PL)
-		cpu->regs->ss = cpu->esp1;
-
-	/*
-	 * Set the code segment and the address to execute.
-	 */
-	cpu->regs->cs = (__KERNEL_CS|GUEST_PL);
-	cpu->regs->eip = idt_address(lo, hi);
-
-	/*
-	 * Trapping always clears these flags:
-	 * TF: Trap flag
-	 * VM: Virtual 8086 mode
-	 * RF: Resume
-	 * NT: Nested task.
-	 */
-	cpu->regs->eflags &=
-		~(X86_EFLAGS_TF|X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT);
-
-	/*
-	 * There are two kinds of interrupt handlers: 0xE is an "interrupt
-	 * gate" which expects interrupts to be disabled on entry.
-	 */
-	if (idt_type(lo, hi) == 0xE)
-		if (put_user(0, &cpu->lg->lguest_data->irq_enabled))
-			kill_guest(cpu, "Disabling interrupts");
-}
-
-/* This restores the eflags word which was pushed on the stack by a trap */
-static void restore_eflags(struct lg_cpu *cpu)
-{
-	/* This is the physical address of the stack. */
-	unsigned long stack_pa = guest_pa(cpu, cpu->regs->esp);
-
-	/*
-	 * Stack looks like this:
-	 * Address	Contents
-	 * esp		EIP
-	 * esp + 4	CS
-	 * esp + 8	EFLAGS
-	 */
-	cpu->regs->eflags = lgread(cpu, stack_pa + 8, u32);
-	cpu->regs->eflags &=
-		~(X86_EFLAGS_TF|X86_EFLAGS_VM|X86_EFLAGS_RF|X86_EFLAGS_NT);
-}
-
-/*H:205
- * Virtual Interrupts.
- *
- * interrupt_pending() returns the first pending interrupt which isn't blocked
- * by the Guest.  It is called before every entry to the Guest, and just before
- * we go to sleep when the Guest has halted itself.
- */
-unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more)
-{
-	unsigned int irq;
-	DECLARE_BITMAP(blk, LGUEST_IRQS);
-
-	/* If the Guest hasn't even initialized yet, we can do nothing. */
-	if (!cpu->lg->lguest_data)
-		return LGUEST_IRQS;
-
-	/*
-	 * Take our "irqs_pending" array and remove any interrupts the Guest
-	 * wants blocked: the result ends up in "blk".
-	 */
-	if (copy_from_user(&blk, cpu->lg->lguest_data->blocked_interrupts,
-			   sizeof(blk)))
-		return LGUEST_IRQS;
-	bitmap_andnot(blk, cpu->irqs_pending, blk, LGUEST_IRQS);
-
-	/* Find the first interrupt. */
-	irq = find_first_bit(blk, LGUEST_IRQS);
-	*more = find_next_bit(blk, LGUEST_IRQS, irq+1);
-
-	return irq;
-}
-
-/*
- * This actually diverts the Guest to running an interrupt handler, once an
- * interrupt has been identified by interrupt_pending().
- */
-void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more)
-{
-	struct desc_struct *idt;
-
-	BUG_ON(irq >= LGUEST_IRQS);
-
-	/* If they're halted, interrupts restart them. */
-	if (cpu->halted) {
-		/* Re-enable interrupts. */
-		if (put_user(X86_EFLAGS_IF, &cpu->lg->lguest_data->irq_enabled))
-			kill_guest(cpu, "Re-enabling interrupts");
-		cpu->halted = 0;
-	} else {
-		/* Otherwise we check if they have interrupts disabled. */
-		u32 irq_enabled;
-		if (get_user(irq_enabled, &cpu->lg->lguest_data->irq_enabled))
-			irq_enabled = 0;
-		if (!irq_enabled) {
-			/* Make sure they know an IRQ is pending. */
-			put_user(X86_EFLAGS_IF,
-				 &cpu->lg->lguest_data->irq_pending);
-			return;
-		}
-	}
-
-	/*
-	 * Look at the IDT entry the Guest gave us for this interrupt.  The
-	 * first 32 (FIRST_EXTERNAL_VECTOR) entries are for traps, so we skip
-	 * over them.
-	 */
-	idt = &cpu->arch.idt[FIRST_EXTERNAL_VECTOR+irq];
-	/* If they don't have a handler (yet?), we just ignore it */
-	if (idt_present(idt->a, idt->b)) {
-		/* OK, mark it no longer pending and deliver it. */
-		clear_bit(irq, cpu->irqs_pending);
-
-		/*
-		 * They may be about to iret, where they asked us never to
-		 * deliver interrupts.  In this case, we can emulate that iret
-		 * then immediately deliver the interrupt.  This is basically
-		 * a noop: the iret would pop the interrupt frame and restore
-		 * eflags, and then we'd set it up again.  So just restore the
-		 * eflags word and jump straight to the handler in this case.
-		 *
-		 * Denys Vlasenko points out that this isn't quite right: if
-		 * the iret was returning to userspace, then that interrupt
-		 * would reset the stack pointer (which the Guest told us
-		 * about via LHCALL_SET_STACK).  But unless the Guest is being
-		 * *really* weird, that will be the same as the current stack
-		 * anyway.
-		 */
-		if (cpu->regs->eip == cpu->lg->noirq_iret) {
-			restore_eflags(cpu);
-		} else {
-			/*
-			 * set_guest_interrupt() takes a flag to say whether
-			 * this interrupt pushes an error code onto the stack
-			 * as well: virtual interrupts never do.
-			 */
-			push_guest_interrupt_stack(cpu, false);
-		}
-		/* Actually make Guest cpu jump to handler. */
-		guest_run_interrupt(cpu, idt->a, idt->b);
-	}
-
-	/*
-	 * Every time we deliver an interrupt, we update the timestamp in the
-	 * Guest's lguest_data struct.  It would be better for the Guest if we
-	 * did this more often, but it can actually be quite slow: doing it
-	 * here is a compromise which means at least it gets updated every
-	 * timer interrupt.
-	 */
-	write_timestamp(cpu);
-
-	/*
-	 * If there are no other interrupts we want to deliver, clear
-	 * the pending flag.
-	 */
-	if (!more)
-		put_user(0, &cpu->lg->lguest_data->irq_pending);
-}
-
-/* And this is the routine when we want to set an interrupt for the Guest. */
-void set_interrupt(struct lg_cpu *cpu, unsigned int irq)
-{
-	/*
-	 * Next time the Guest runs, the core code will see if it can deliver
-	 * this interrupt.
-	 */
-	set_bit(irq, cpu->irqs_pending);
-
-	/*
-	 * Make sure it sees it; it might be asleep (eg. halted), or running
-	 * the Guest right now, in which case kick_process() will knock it out.
-	 */
-	if (!wake_up_process(cpu->tsk))
-		kick_process(cpu->tsk);
-}
-/*:*/
-
-/*
- * Linux uses trap 128 for system calls.  Plan9 uses 64, and Ron Minnich sent
- * me a patch, so we support that too.  It'd be a big step for lguest if half
- * the Plan 9 user base were to start using it.
- *
- * Actually now I think of it, it's possible that Ron *is* half the Plan 9
- * userbase.  Oh well.
- */
-bool could_be_syscall(unsigned int num)
-{
-	/* Normal Linux IA32_SYSCALL_VECTOR or reserved vector? */
-	return num == IA32_SYSCALL_VECTOR || num == syscall_vector;
-}
-
-/* The syscall vector it wants must be unused by Host. */
-bool check_syscall_vector(struct lguest *lg)
-{
-	u32 vector;
-
-	if (get_user(vector, &lg->lguest_data->syscall_vec))
-		return false;
-
-	return could_be_syscall(vector);
-}
-
-int init_interrupts(void)
-{
-	/* If they want some strange system call vector, reserve it now */
-	if (syscall_vector != IA32_SYSCALL_VECTOR) {
-		if (test_bit(syscall_vector, used_vectors) ||
-		    vector_used_by_percpu_irq(syscall_vector)) {
-			printk(KERN_ERR "lg: couldn't reserve syscall %u\n",
-				 syscall_vector);
-			return -EBUSY;
-		}
-		set_bit(syscall_vector, used_vectors);
-	}
-
-	return 0;
-}
-
-void free_interrupts(void)
-{
-	if (syscall_vector != IA32_SYSCALL_VECTOR)
-		clear_bit(syscall_vector, used_vectors);
-}
-
-/*H:220
- * Now we've got the routines to deliver interrupts, delivering traps like
- * page fault is easy.  The only trick is that Intel decided that some traps
- * should have error codes:
- */
-static bool has_err(unsigned int trap)
-{
-	return (trap == 8 || (trap >= 10 && trap <= 14) || trap == 17);
-}
-
-/* deliver_trap() returns true if it could deliver the trap. */
-bool deliver_trap(struct lg_cpu *cpu, unsigned int num)
-{
-	/*
-	 * Trap numbers are always 8 bit, but we set an impossible trap number
-	 * for traps inside the Switcher, so check that here.
-	 */
-	if (num >= ARRAY_SIZE(cpu->arch.idt))
-		return false;
-
-	/*
-	 * Early on the Guest hasn't set the IDT entries (or maybe it put a
-	 * bogus one in): if we fail here, the Guest will be killed.
-	 */
-	if (!idt_present(cpu->arch.idt[num].a, cpu->arch.idt[num].b))
-		return false;
-	push_guest_interrupt_stack(cpu, has_err(num));
-	guest_run_interrupt(cpu, cpu->arch.idt[num].a,
-			    cpu->arch.idt[num].b);
-	return true;
-}
-
-/*H:250
- * Here's the hard part: returning to the Host every time a trap happens
- * and then calling deliver_trap() and re-entering the Guest is slow.
- * Particularly because Guest userspace system calls are traps (usually trap
- * 128).
- *
- * So we'd like to set up the IDT to tell the CPU to deliver traps directly
- * into the Guest.  This is possible, but the complexities cause the size of
- * this file to double!  However, 150 lines of code is worth writing for taking
- * system calls down from 1750ns to 270ns.  Plus, if lguest didn't do it, all
- * the other hypervisors would beat it up at lunchtime.
- *
- * This routine indicates if a particular trap number could be delivered
- * directly.
- *
- * Unfortunately, Linux 4.6 started using an interrupt gate instead of a
- * trap gate for syscalls, so this trick is ineffective.  See Mastery for
- * how we could do this anyway...
- */
-static bool direct_trap(unsigned int num)
-{
-	/*
-	 * Hardware interrupts don't go to the Guest at all (except system
-	 * call).
-	 */
-	if (num >= FIRST_EXTERNAL_VECTOR && !could_be_syscall(num))
-		return false;
-
-	/*
-	 * The Host needs to see page faults (for shadow paging and to save the
-	 * fault address), general protection faults (in/out emulation) and
-	 * device not available (TS handling) and of course, the hypercall trap.
-	 */
-	return num != 14 && num != 13 && num != 7 && num != LGUEST_TRAP_ENTRY;
-}
-/*:*/
-
-/*M:005
- * The Guest has the ability to turn its interrupt gates into trap gates,
- * if it is careful.  The Host will let trap gates can go directly to the
- * Guest, but the Guest needs the interrupts atomically disabled for an
- * interrupt gate.  The Host could provide a mechanism to register more
- * "no-interrupt" regions, and the Guest could point the trap gate at
- * instructions within that region, where it can safely disable interrupts.
- */
-
-/*M:006
- * The Guests do not use the sysenter (fast system call) instruction,
- * because it's hardcoded to enter privilege level 0 and so can't go direct.
- * It's about twice as fast as the older "int 0x80" system call, so it might
- * still be worthwhile to handle it in the Switcher and lcall down to the
- * Guest.  The sysenter semantics are hairy tho: search for that keyword in
- * entry.S
-:*/
-
-/*H:260
- * When we make traps go directly into the Guest, we need to make sure
- * the kernel stack is valid (ie. mapped in the page tables).  Otherwise, the
- * CPU trying to deliver the trap will fault while trying to push the interrupt
- * words on the stack: this is called a double fault, and it forces us to kill
- * the Guest.
- *
- * Which is deeply unfair, because (literally!) it wasn't the Guests' fault.
- */
-void pin_stack_pages(struct lg_cpu *cpu)
-{
-	unsigned int i;
-
-	/*
-	 * Depending on the CONFIG_4KSTACKS option, the Guest can have one or
-	 * two pages of stack space.
-	 */
-	for (i = 0; i < cpu->lg->stack_pages; i++)
-		/*
-		 * The stack grows *upwards*, so the address we're given is the
-		 * start of the page after the kernel stack.  Subtract one to
-		 * get back onto the first stack page, and keep subtracting to
-		 * get to the rest of the stack pages.
-		 */
-		pin_page(cpu, cpu->esp1 - 1 - i * PAGE_SIZE);
-}
-
-/*
- * Direct traps also mean that we need to know whenever the Guest wants to use
- * a different kernel stack, so we can change the guest TSS to use that
- * stack.  The TSS entries expect a virtual address, so unlike most addresses
- * the Guest gives us, the "esp" (stack pointer) value here is virtual, not
- * physical.
- *
- * In Linux each process has its own kernel stack, so this happens a lot: we
- * change stacks on each context switch.
- */
-void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages)
-{
-	/*
-	 * You're not allowed a stack segment with privilege level 0: bad Guest!
-	 */
-	if ((seg & 0x3) != GUEST_PL)
-		kill_guest(cpu, "bad stack segment %i", seg);
-	/* We only expect one or two stack pages. */
-	if (pages > 2)
-		kill_guest(cpu, "bad stack pages %u", pages);
-	/* Save where the stack is, and how many pages */
-	cpu->ss1 = seg;
-	cpu->esp1 = esp;
-	cpu->lg->stack_pages = pages;
-	/* Make sure the new stack pages are mapped */
-	pin_stack_pages(cpu);
-}
-
-/*
- * All this reference to mapping stacks leads us neatly into the other complex
- * part of the Host: page table handling.
- */
-
-/*H:235
- * This is the routine which actually checks the Guest's IDT entry and
- * transfers it into the entry in "struct lguest":
- */
-static void set_trap(struct lg_cpu *cpu, struct desc_struct *trap,
-		     unsigned int num, u32 lo, u32 hi)
-{
-	u8 type = idt_type(lo, hi);
-
-	/* We zero-out a not-present entry */
-	if (!idt_present(lo, hi)) {
-		trap->a = trap->b = 0;
-		return;
-	}
-
-	/* We only support interrupt and trap gates. */
-	if (type != 0xE && type != 0xF)
-		kill_guest(cpu, "bad IDT type %i", type);
-
-	/*
-	 * We only copy the handler address, present bit, privilege level and
-	 * type.  The privilege level controls where the trap can be triggered
-	 * manually with an "int" instruction.  This is usually GUEST_PL,
-	 * except for system calls which userspace can use.
-	 */
-	trap->a = ((__KERNEL_CS|GUEST_PL)<<16) | (lo&0x0000FFFF);
-	trap->b = (hi&0xFFFFEF00);
-}
-
-/*H:230
- * While we're here, dealing with delivering traps and interrupts to the
- * Guest, we might as well complete the picture: how the Guest tells us where
- * it wants them to go.  This would be simple, except making traps fast
- * requires some tricks.
- *
- * We saw the Guest setting Interrupt Descriptor Table (IDT) entries with the
- * LHCALL_LOAD_IDT_ENTRY hypercall before: that comes here.
- */
-void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int num, u32 lo, u32 hi)
-{
-	/*
-	 * Guest never handles: NMI, doublefault, spurious interrupt or
-	 * hypercall.  We ignore when it tries to set them.
-	 */
-	if (num == 2 || num == 8 || num == 15 || num == LGUEST_TRAP_ENTRY)
-		return;
-
-	/*
-	 * Mark the IDT as changed: next time the Guest runs we'll know we have
-	 * to copy this again.
-	 */
-	cpu->changed |= CHANGED_IDT;
-
-	/* Check that the Guest doesn't try to step outside the bounds. */
-	if (num >= ARRAY_SIZE(cpu->arch.idt))
-		kill_guest(cpu, "Setting idt entry %u", num);
-	else
-		set_trap(cpu, &cpu->arch.idt[num], num, lo, hi);
-}
-
-/*
- * The default entry for each interrupt points into the Switcher routines which
- * simply return to the Host.  The run_guest() loop will then call
- * deliver_trap() to bounce it back into the Guest.
- */
-static void default_idt_entry(struct desc_struct *idt,
-			      int trap,
-			      const unsigned long handler,
-			      const struct desc_struct *base)
-{
-	/* A present interrupt gate. */
-	u32 flags = 0x8e00;
-
-	/*
-	 * Set the privilege level on the entry for the hypercall: this allows
-	 * the Guest to use the "int" instruction to trigger it.
-	 */
-	if (trap == LGUEST_TRAP_ENTRY)
-		flags |= (GUEST_PL << 13);
-	else if (base)
-		/*
-		 * Copy privilege level from what Guest asked for.  This allows
-		 * debug (int 3) traps from Guest userspace, for example.
-		 */
-		flags |= (base->b & 0x6000);
-
-	/* Now pack it into the IDT entry in its weird format. */
-	idt->a = (LGUEST_CS<<16) | (handler&0x0000FFFF);
-	idt->b = (handler&0xFFFF0000) | flags;
-}
-
-/* When the Guest first starts, we put default entries into the IDT. */
-void setup_default_idt_entries(struct lguest_ro_state *state,
-			       const unsigned long *def)
-{
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(state->guest_idt); i++)
-		default_idt_entry(&state->guest_idt[i], i, def[i], NULL);
-}
-
-/*H:240
- * We don't use the IDT entries in the "struct lguest" directly, instead
- * we copy them into the IDT which we've set up for Guests on this CPU, just
- * before we run the Guest.  This routine does that copy.
- */
-void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
-		const unsigned long *def)
-{
-	unsigned int i;
-
-	/*
-	 * We can simply copy the direct traps, otherwise we use the default
-	 * ones in the Switcher: they will return to the Host.
-	 */
-	for (i = 0; i < ARRAY_SIZE(cpu->arch.idt); i++) {
-		const struct desc_struct *gidt = &cpu->arch.idt[i];
-
-		/* If no Guest can ever override this trap, leave it alone. */
-		if (!direct_trap(i))
-			continue;
-
-		/*
-		 * Only trap gates (type 15) can go direct to the Guest.
-		 * Interrupt gates (type 14) disable interrupts as they are
-		 * entered, which we never let the Guest do.  Not present
-		 * entries (type 0x0) also can't go direct, of course.
-		 *
-		 * If it can't go direct, we still need to copy the priv. level:
-		 * they might want to give userspace access to a software
-		 * interrupt.
-		 */
-		if (idt_type(gidt->a, gidt->b) == 0xF)
-			idt[i] = *gidt;
-		else
-			default_idt_entry(&idt[i], i, def[i], gidt);
-	}
-}
-
-/*H:200
- * The Guest Clock.
- *
- * There are two sources of virtual interrupts.  We saw one in lguest_user.c:
- * the Launcher sending interrupts for virtual devices.  The other is the Guest
- * timer interrupt.
- *
- * The Guest uses the LHCALL_SET_CLOCKEVENT hypercall to tell us how long to
- * the next timer interrupt (in nanoseconds).  We use the high-resolution timer
- * infrastructure to set a callback at that time.
- *
- * 0 means "turn off the clock".
- */
-void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta)
-{
-	ktime_t expires;
-
-	if (unlikely(delta == 0)) {
-		/* Clock event device is shutting down. */
-		hrtimer_cancel(&cpu->hrt);
-		return;
-	}
-
-	/*
-	 * We use wallclock time here, so the Guest might not be running for
-	 * all the time between now and the timer interrupt it asked for.  This
-	 * is almost always the right thing to do.
-	 */
-	expires = ktime_add_ns(ktime_get_real(), delta);
-	hrtimer_start(&cpu->hrt, expires, HRTIMER_MODE_ABS);
-}
-
-/* This is the function called when the Guest's timer expires. */
-static enum hrtimer_restart clockdev_fn(struct hrtimer *timer)
-{
-	struct lg_cpu *cpu = container_of(timer, struct lg_cpu, hrt);
-
-	/* Remember the first interrupt is the timer interrupt. */
-	set_interrupt(cpu, 0);
-	return HRTIMER_NORESTART;
-}
-
-/* This sets up the timer for this Guest. */
-void init_clockdev(struct lg_cpu *cpu)
-{
-	hrtimer_init(&cpu->hrt, CLOCK_REALTIME, HRTIMER_MODE_ABS);
-	cpu->hrt.function = clockdev_fn;
-}
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
deleted file mode 100644
index 2356a2318034..000000000000
--- a/drivers/lguest/lg.h
+++ /dev/null
@@ -1,258 +0,0 @@
-#ifndef _LGUEST_H
-#define _LGUEST_H
-
-#ifndef __ASSEMBLY__
-#include <linux/types.h>
-#include <linux/init.h>
-#include <linux/stringify.h>
-#include <linux/lguest.h>
-#include <linux/lguest_launcher.h>
-#include <linux/wait.h>
-#include <linux/hrtimer.h>
-#include <linux/err.h>
-#include <linux/slab.h>
-
-#include <asm/lguest.h>
-
-struct pgdir {
-	unsigned long gpgdir;
-	bool switcher_mapped;
-	int last_host_cpu;
-	pgd_t *pgdir;
-};
-
-/* We have two pages shared with guests, per cpu.  */
-struct lguest_pages {
-	/* This is the stack page mapped rw in guest */
-	char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
-	struct lguest_regs regs;
-
-	/* This is the host state & guest descriptor page, ro in guest */
-	struct lguest_ro_state state;
-} __attribute__((aligned(PAGE_SIZE)));
-
-#define CHANGED_IDT		1
-#define CHANGED_GDT		2
-#define CHANGED_GDT_TLS		4 /* Actually a subset of CHANGED_GDT */
-#define CHANGED_ALL	        3
-
-struct lg_cpu {
-	unsigned int id;
-	struct lguest *lg;
-	struct task_struct *tsk;
-	struct mm_struct *mm; 	/* == tsk->mm, but that becomes NULL on exit */
-
-	u32 cr2;
-	u32 esp1;
-	u16 ss1;
-
-	/* Bitmap of what has changed: see CHANGED_* above. */
-	int changed;
-
-	/* Pending operation. */
-	struct lguest_pending pending;
-
-	unsigned long *reg_read; /* register from LHREQ_GETREG */
-
-	/* At end of a page shared mapped over lguest_pages in guest. */
-	unsigned long regs_page;
-	struct lguest_regs *regs;
-
-	struct lguest_pages *last_pages;
-
-	/* Initialization mode: linear map everything. */
-	bool linear_pages;
-	int cpu_pgd; /* Which pgd this cpu is currently using */
-
-	/* If a hypercall was asked for, this points to the arguments. */
-	struct hcall_args *hcall;
-	u32 next_hcall;
-
-	/* Virtual clock device */
-	struct hrtimer hrt;
-
-	/* Did the Guest tell us to halt? */
-	int halted;
-
-	/* Pending virtual interrupts */
-	DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
-
-	struct lg_cpu_arch arch;
-};
-
-/* The private info the thread maintains about the guest. */
-struct lguest {
-	struct lguest_data __user *lguest_data;
-	struct lg_cpu cpus[NR_CPUS];
-	unsigned int nr_cpus;
-
-	/* Valid guest memory pages must be < this. */
-	u32 pfn_limit;
-
-	/* Device memory is >= pfn_limit and < device_limit. */
-	u32 device_limit;
-
-	/*
-	 * This provides the offset to the base of guest-physical memory in the
-	 * Launcher.
-	 */
-	void __user *mem_base;
-	unsigned long kernel_address;
-
-	struct pgdir pgdirs[4];
-
-	unsigned long noirq_iret;
-
-	unsigned int stack_pages;
-	u32 tsc_khz;
-
-	/* Dead? */
-	const char *dead;
-};
-
-extern struct mutex lguest_lock;
-
-/* core.c: */
-bool lguest_address_ok(const struct lguest *lg,
-		       unsigned long addr, unsigned long len);
-void __lgread(struct lg_cpu *, void *, unsigned long, unsigned);
-void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned);
-extern struct page **lg_switcher_pages;
-
-/*H:035
- * Using memory-copy operations like that is usually inconvient, so we
- * have the following helper macros which read and write a specific type (often
- * an unsigned long).
- *
- * This reads into a variable of the given type then returns that.
- */
-#define lgread(cpu, addr, type)						\
-	({ type _v; __lgread((cpu), &_v, (addr), sizeof(_v)); _v; })
-
-/* This checks that the variable is of the given type, then writes it out. */
-#define lgwrite(cpu, addr, type, val)				\
-	do {							\
-		typecheck(type, val);				\
-		__lgwrite((cpu), (addr), &(val), sizeof(val));	\
-	} while(0)
-/* (end of memory access helper routines) :*/
-
-int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
-
-/*
- * Helper macros to obtain the first 12 or the last 20 bits, this is only the
- * first step in the migration to the kernel types.  pte_pfn is already defined
- * in the kernel.
- */
-#define pgd_flags(x)	(pgd_val(x) & ~PAGE_MASK)
-#define pgd_pfn(x)	(pgd_val(x) >> PAGE_SHIFT)
-#define pmd_flags(x)    (pmd_val(x) & ~PAGE_MASK)
-#define pmd_pfn(x)	(pmd_val(x) >> PAGE_SHIFT)
-
-/* interrupts_and_traps.c: */
-unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more);
-void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more);
-void set_interrupt(struct lg_cpu *cpu, unsigned int irq);
-bool deliver_trap(struct lg_cpu *cpu, unsigned int num);
-void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
-			  u32 low, u32 hi);
-void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);
-void pin_stack_pages(struct lg_cpu *cpu);
-void setup_default_idt_entries(struct lguest_ro_state *state,
-			       const unsigned long *def);
-void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
-		const unsigned long *def);
-void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
-bool send_notify_to_eventfd(struct lg_cpu *cpu);
-void init_clockdev(struct lg_cpu *cpu);
-bool check_syscall_vector(struct lguest *lg);
-bool could_be_syscall(unsigned int num);
-int init_interrupts(void);
-void free_interrupts(void);
-
-/* segments.c: */
-void setup_default_gdt_entries(struct lguest_ro_state *state);
-void setup_guest_gdt(struct lg_cpu *cpu);
-void load_guest_gdt_entry(struct lg_cpu *cpu, unsigned int i,
-			  u32 low, u32 hi);
-void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
-void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
-void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
-
-/* page_tables.c: */
-int init_guest_pagetable(struct lguest *lg);
-void free_guest_pagetable(struct lguest *lg);
-void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
-void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
-#ifdef CONFIG_X86_PAE
-void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
-#endif
-void guest_pagetable_clear_all(struct lg_cpu *cpu);
-void guest_pagetable_flush_user(struct lg_cpu *cpu);
-void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
-		   unsigned long vaddr, pte_t val);
-void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
-bool demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode,
-		 unsigned long *iomem);
-void pin_page(struct lg_cpu *cpu, unsigned long vaddr);
-bool __guest_pa(struct lg_cpu *cpu, unsigned long vaddr, unsigned long *paddr);
-unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr);
-void page_table_guest_data_init(struct lg_cpu *cpu);
-
-/* <arch>/core.c: */
-void lguest_arch_host_init(void);
-void lguest_arch_host_fini(void);
-void lguest_arch_run_guest(struct lg_cpu *cpu);
-void lguest_arch_handle_trap(struct lg_cpu *cpu);
-int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
-int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
-void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
-unsigned long *lguest_arch_regptr(struct lg_cpu *cpu, size_t reg_off, bool any);
-
-/* <arch>/switcher.S: */
-extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
-
-/* lguest_user.c: */
-int lguest_device_init(void);
-void lguest_device_remove(void);
-
-/* hypercalls.c: */
-void do_hypercalls(struct lg_cpu *cpu);
-void write_timestamp(struct lg_cpu *cpu);
-
-/*L:035
- * Let's step aside for the moment, to study one important routine that's used
- * widely in the Host code.
- *
- * There are many cases where the Guest can do something invalid, like pass crap
- * to a hypercall.  Since only the Guest kernel can make hypercalls, it's quite
- * acceptable to simply terminate the Guest and give the Launcher a nicely
- * formatted reason.  It's also simpler for the Guest itself, which doesn't
- * need to check most hypercalls for "success"; if you're still running, it
- * succeeded.
- *
- * Once this is called, the Guest will never run again, so most Host code can
- * call this then continue as if nothing had happened.  This means many
- * functions don't have to explicitly return an error code, which keeps the
- * code simple.
- *
- * It also means that this can be called more than once: only the first one is
- * remembered.  The only trick is that we still need to kill the Guest even if
- * we can't allocate memory to store the reason.  Linux has a neat way of
- * packing error codes into invalid pointers, so we use that here.
- *
- * Like any macro which uses an "if", it is safely wrapped in a run-once "do {
- * } while(0)".
- */
-#define kill_guest(cpu, fmt...)					\
-do {								\
-	if (!(cpu)->lg->dead) {					\
-		(cpu)->lg->dead = kasprintf(GFP_ATOMIC, fmt);	\
-		if (!(cpu)->lg->dead)				\
-			(cpu)->lg->dead = ERR_PTR(-ENOMEM);	\
-	}							\
-} while(0)
-/* (End of aside) :*/
-
-#endif	/* __ASSEMBLY__ */
-#endif	/* _LGUEST_H */
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
deleted file mode 100644
index 1a6787bc9386..000000000000
--- a/drivers/lguest/lguest_user.c
+++ /dev/null
@@ -1,446 +0,0 @@
-/*P:200 This contains all the /dev/lguest code, whereby the userspace
- * launcher controls and communicates with the Guest.  For example,
- * the first write will tell us the Guest's memory layout and entry
- * point.  A read will run the Guest until something happens, such as
- * a signal or the Guest accessing a device.
-:*/
-#include <linux/uaccess.h>
-#include <linux/miscdevice.h>
-#include <linux/fs.h>
-#include <linux/sched.h>
-#include <linux/sched/mm.h>
-#include <linux/file.h>
-#include <linux/slab.h>
-#include <linux/export.h>
-#include "lg.h"
-
-/*L:052
-  The Launcher can get the registers, and also set some of them.
-*/
-static int getreg_setup(struct lg_cpu *cpu, const unsigned long __user *input)
-{
-	unsigned long which;
-
-	/* We re-use the ptrace structure to specify which register to read. */
-	if (get_user(which, input) != 0)
-		return -EFAULT;
-
-	/*
-	 * We set up the cpu register pointer, and their next read will
-	 * actually get the value (instead of running the guest).
-	 *
-	 * The last argument 'true' says we can access any register.
-	 */
-	cpu->reg_read = lguest_arch_regptr(cpu, which, true);
-	if (!cpu->reg_read)
-		return -ENOENT;
-
-	/* And because this is a write() call, we return the length used. */
-	return sizeof(unsigned long) * 2;
-}
-
-static int setreg(struct lg_cpu *cpu, const unsigned long __user *input)
-{
-	unsigned long which, value, *reg;
-
-	/* We re-use the ptrace structure to specify which register to read. */
-	if (get_user(which, input) != 0)
-		return -EFAULT;
-	input++;
-	if (get_user(value, input) != 0)
-		return -EFAULT;
-
-	/* The last argument 'false' means we can't access all registers. */
-	reg = lguest_arch_regptr(cpu, which, false);
-	if (!reg)
-		return -ENOENT;
-
-	*reg = value;
-
-	/* And because this is a write() call, we return the length used. */
-	return sizeof(unsigned long) * 3;
-}
-
-/*L:050
- * Sending an interrupt is done by writing LHREQ_IRQ and an interrupt
- * number to /dev/lguest.
- */
-static int user_send_irq(struct lg_cpu *cpu, const unsigned long __user *input)
-{
-	unsigned long irq;
-
-	if (get_user(irq, input) != 0)
-		return -EFAULT;
-	if (irq >= LGUEST_IRQS)
-		return -EINVAL;
-
-	/*
-	 * Next time the Guest runs, the core code will see if it can deliver
-	 * this interrupt.
-	 */
-	set_interrupt(cpu, irq);
-	return 0;
-}
-
-/*L:053
- * Deliver a trap: this is used by the Launcher if it can't emulate
- * an instruction.
- */
-static int trap(struct lg_cpu *cpu, const unsigned long __user *input)
-{
-	unsigned long trapnum;
-
-	if (get_user(trapnum, input) != 0)
-		return -EFAULT;
-
-	if (!deliver_trap(cpu, trapnum))
-		return -EINVAL;
-
-	return 0;
-}
-
-/*L:040
- * Once our Guest is initialized, the Launcher makes it run by reading
- * from /dev/lguest.
- */
-static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
-{
-	struct lguest *lg = file->private_data;
-	struct lg_cpu *cpu;
-	unsigned int cpu_id = *o;
-
-	/* You must write LHREQ_INITIALIZE first! */
-	if (!lg)
-		return -EINVAL;
-
-	/* Watch out for arbitrary vcpu indexes! */
-	if (cpu_id >= lg->nr_cpus)
-		return -EINVAL;
-
-	cpu = &lg->cpus[cpu_id];
-
-	/* If you're not the task which owns the Guest, go away. */
-	if (current != cpu->tsk)
-		return -EPERM;
-
-	/* If the Guest is already dead, we indicate why */
-	if (lg->dead) {
-		size_t len;
-
-		/* lg->dead either contains an error code, or a string. */
-		if (IS_ERR(lg->dead))
-			return PTR_ERR(lg->dead);
-
-		/* We can only return as much as the buffer they read with. */
-		len = min(size, strlen(lg->dead)+1);
-		if (copy_to_user(user, lg->dead, len) != 0)
-			return -EFAULT;
-		return len;
-	}
-
-	/*
-	 * If we returned from read() last time because the Guest sent I/O,
-	 * clear the flag.
-	 */
-	if (cpu->pending.trap)
-		cpu->pending.trap = 0;
-
-	/* Run the Guest until something interesting happens. */
-	return run_guest(cpu, (unsigned long __user *)user);
-}
-
-/*L:025
- * This actually initializes a CPU.  For the moment, a Guest is only
- * uniprocessor, so "id" is always 0.
- */
-static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip)
-{
-	/* We have a limited number of CPUs in the lguest struct. */
-	if (id >= ARRAY_SIZE(cpu->lg->cpus))
-		return -EINVAL;
-
-	/* Set up this CPU's id, and pointer back to the lguest struct. */
-	cpu->id = id;
-	cpu->lg = container_of(cpu, struct lguest, cpus[id]);
-	cpu->lg->nr_cpus++;
-
-	/* Each CPU has a timer it can set. */
-	init_clockdev(cpu);
-
-	/*
-	 * We need a complete page for the Guest registers: they are accessible
-	 * to the Guest and we can only grant it access to whole pages.
-	 */
-	cpu->regs_page = get_zeroed_page(GFP_KERNEL);
-	if (!cpu->regs_page)
-		return -ENOMEM;
-
-	/* We actually put the registers at the end of the page. */
-	cpu->regs = (void *)cpu->regs_page + PAGE_SIZE - sizeof(*cpu->regs);
-
-	/*
-	 * Now we initialize the Guest's registers, handing it the start
-	 * address.
-	 */
-	lguest_arch_setup_regs(cpu, start_ip);
-
-	/*
-	 * We keep a pointer to the Launcher task (ie. current task) for when
-	 * other Guests want to wake this one (eg. console input).
-	 */
-	cpu->tsk = current;
-
-	/*
-	 * We need to keep a pointer to the Launcher's memory map, because if
-	 * the Launcher dies we need to clean it up.  If we don't keep a
-	 * reference, it is destroyed before close() is called.
-	 */
-	cpu->mm = get_task_mm(cpu->tsk);
-
-	/*
-	 * We remember which CPU's pages this Guest used last, for optimization
-	 * when the same Guest runs on the same CPU twice.
-	 */
-	cpu->last_pages = NULL;
-
-	/* No error == success. */
-	return 0;
-}
-
-/*L:020
- * The initialization write supplies 3 pointer sized (32 or 64 bit) values (in
- * addition to the LHREQ_INITIALIZE value).  These are:
- *
- * base: The start of the Guest-physical memory inside the Launcher memory.
- *
- * pfnlimit: The highest (Guest-physical) page number the Guest should be
- * allowed to access.  The Guest memory lives inside the Launcher, so it sets
- * this to ensure the Guest can only reach its own memory.
- *
- * start: The first instruction to execute ("eip" in x86-speak).
- */
-static int initialize(struct file *file, const unsigned long __user *input)
-{
-	/* "struct lguest" contains all we (the Host) know about a Guest. */
-	struct lguest *lg;
-	int err;
-	unsigned long args[4];
-
-	/*
-	 * We grab the Big Lguest lock, which protects against multiple
-	 * simultaneous initializations.
-	 */
-	mutex_lock(&lguest_lock);
-	/* You can't initialize twice!  Close the device and start again... */
-	if (file->private_data) {
-		err = -EBUSY;
-		goto unlock;
-	}
-
-	if (copy_from_user(args, input, sizeof(args)) != 0) {
-		err = -EFAULT;
-		goto unlock;
-	}
-
-	lg = kzalloc(sizeof(*lg), GFP_KERNEL);
-	if (!lg) {
-		err = -ENOMEM;
-		goto unlock;
-	}
-
-	/* Populate the easy fields of our "struct lguest" */
-	lg->mem_base = (void __user *)args[0];
-	lg->pfn_limit = args[1];
-	lg->device_limit = args[3];
-
-	/* This is the first cpu (cpu 0) and it will start booting at args[2] */
-	err = lg_cpu_start(&lg->cpus[0], 0, args[2]);
-	if (err)
-		goto free_lg;
-
-	/*
-	 * Initialize the Guest's shadow page tables.  This allocates
-	 * memory, so can fail.
-	 */
-	err = init_guest_pagetable(lg);
-	if (err)
-		goto free_regs;
-
-	/* We keep our "struct lguest" in the file's private_data. */
-	file->private_data = lg;
-
-	mutex_unlock(&lguest_lock);
-
-	/* And because this is a write() call, we return the length used. */
-	return sizeof(args);
-
-free_regs:
-	/* FIXME: This should be in free_vcpu */
-	free_page(lg->cpus[0].regs_page);
-free_lg:
-	kfree(lg);
-unlock:
-	mutex_unlock(&lguest_lock);
-	return err;
-}
-
-/*L:010
- * The first operation the Launcher does must be a write.  All writes
- * start with an unsigned long number: for the first write this must be
- * LHREQ_INITIALIZE to set up the Guest.  After that the Launcher can use
- * writes of other values to send interrupts or set up receipt of notifications.
- *
- * Note that we overload the "offset" in the /dev/lguest file to indicate what
- * CPU number we're dealing with.  Currently this is always 0 since we only
- * support uniprocessor Guests, but you can see the beginnings of SMP support
- * here.
- */
-static ssize_t write(struct file *file, const char __user *in,
-		     size_t size, loff_t *off)
-{
-	/*
-	 * Once the Guest is initialized, we hold the "struct lguest" in the
-	 * file private data.
-	 */
-	struct lguest *lg = file->private_data;
-	const unsigned long __user *input = (const unsigned long __user *)in;
-	unsigned long req;
-	struct lg_cpu *uninitialized_var(cpu);
-	unsigned int cpu_id = *off;
-
-	/* The first value tells us what this request is. */
-	if (get_user(req, input) != 0)
-		return -EFAULT;
-	input++;
-
-	/* If you haven't initialized, you must do that first. */
-	if (req != LHREQ_INITIALIZE) {
-		if (!lg || (cpu_id >= lg->nr_cpus))
-			return -EINVAL;
-		cpu = &lg->cpus[cpu_id];
-
-		/* Once the Guest is dead, you can only read() why it died. */
-		if (lg->dead)
-			return -ENOENT;
-	}
-
-	switch (req) {
-	case LHREQ_INITIALIZE:
-		return initialize(file, input);
-	case LHREQ_IRQ:
-		return user_send_irq(cpu, input);
-	case LHREQ_GETREG:
-		return getreg_setup(cpu, input);
-	case LHREQ_SETREG:
-		return setreg(cpu, input);
-	case LHREQ_TRAP:
-		return trap(cpu, input);
-	default:
-		return -EINVAL;
-	}
-}
-
-static int open(struct inode *inode, struct file *file)
-{
-	file->private_data = NULL;
-
-	return 0;
-}
-
-/*L:060
- * The final piece of interface code is the close() routine.  It reverses
- * everything done in initialize().  This is usually called because the
- * Launcher exited.
- *
- * Note that the close routine returns 0 or a negative error number: it can't
- * really fail, but it can whine.  I blame Sun for this wart, and K&R C for
- * letting them do it.
-:*/
-static int close(struct inode *inode, struct file *file)
-{
-	struct lguest *lg = file->private_data;
-	unsigned int i;
-
-	/* If we never successfully initialized, there's nothing to clean up */
-	if (!lg)
-		return 0;
-
-	/*
-	 * We need the big lock, to protect from inter-guest I/O and other
-	 * Launchers initializing guests.
-	 */
-	mutex_lock(&lguest_lock);
-
-	/* Free up the shadow page tables for the Guest. */
-	free_guest_pagetable(lg);
-
-	for (i = 0; i < lg->nr_cpus; i++) {
-		/* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */
-		hrtimer_cancel(&lg->cpus[i].hrt);
-		/* We can free up the register page we allocated. */
-		free_page(lg->cpus[i].regs_page);
-		/*
-		 * Now all the memory cleanups are done, it's safe to release
-		 * the Launcher's memory management structure.
-		 */
-		mmput(lg->cpus[i].mm);
-	}
-
-	/*
-	 * If lg->dead doesn't contain an error code it will be NULL or a
-	 * kmalloc()ed string, either of which is ok to hand to kfree().
-	 */
-	if (!IS_ERR(lg->dead))
-		kfree(lg->dead);
-	/* Free the memory allocated to the lguest_struct */
-	kfree(lg);
-	/* Release lock and exit. */
-	mutex_unlock(&lguest_lock);
-
-	return 0;
-}
-
-/*L:000
- * Welcome to our journey through the Launcher!
- *
- * The Launcher is the Host userspace program which sets up, runs and services
- * the Guest.  In fact, many comments in the Drivers which refer to "the Host"
- * doing things are inaccurate: the Launcher does all the device handling for
- * the Guest, but the Guest can't know that.
- *
- * Just to confuse you: to the Host kernel, the Launcher *is* the Guest and we
- * shall see more of that later.
- *
- * We begin our understanding with the Host kernel interface which the Launcher
- * uses: reading and writing a character device called /dev/lguest.  All the
- * work happens in the read(), write() and close() routines:
- */
-static const struct file_operations lguest_fops = {
-	.owner	 = THIS_MODULE,
-	.open	 = open,
-	.release = close,
-	.write	 = write,
-	.read	 = read,
-	.llseek  = default_llseek,
-};
-/*:*/
-
-/*
- * This is a textbook example of a "misc" character device.  Populate a "struct
- * miscdevice" and register it with misc_register().
- */
-static struct miscdevice lguest_dev = {
-	.minor	= MISC_DYNAMIC_MINOR,
-	.name	= "lguest",
-	.fops	= &lguest_fops,
-};
-
-int __init lguest_device_init(void)
-{
-	return misc_register(&lguest_dev);
-}
-
-void __exit lguest_device_remove(void)
-{
-	misc_deregister(&lguest_dev);
-}
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c
deleted file mode 100644
index 0bc127e9f16a..000000000000
--- a/drivers/lguest/page_tables.c
+++ /dev/null
@@ -1,1239 +0,0 @@
-/*P:700
- * The pagetable code, on the other hand, still shows the scars of
- * previous encounters.  It's functional, and as neat as it can be in the
- * circumstances, but be wary, for these things are subtle and break easily.
- * The Guest provides a virtual to physical mapping, but we can neither trust
- * it nor use it: we verify and convert it here then point the CPU to the
- * converted Guest pages when running the Guest.
-:*/
-
-/* Copyright (C) Rusty Russell IBM Corporation 2013.
- * GPL v2 and any later version */
-#include <linux/mm.h>
-#include <linux/gfp.h>
-#include <linux/types.h>
-#include <linux/spinlock.h>
-#include <linux/random.h>
-#include <linux/percpu.h>
-#include <asm/tlbflush.h>
-#include <linux/uaccess.h>
-#include "lg.h"
-
-/*M:008
- * We hold reference to pages, which prevents them from being swapped.
- * It'd be nice to have a callback in the "struct mm_struct" when Linux wants
- * to swap out.  If we had this, and a shrinker callback to trim PTE pages, we
- * could probably consider launching Guests as non-root.
-:*/
-
-/*H:300
- * The Page Table Code
- *
- * We use two-level page tables for the Guest, or three-level with PAE.  If
- * you're not entirely comfortable with virtual addresses, physical addresses
- * and page tables then I recommend you review arch/x86/lguest/boot.c's "Page
- * Table Handling" (with diagrams!).
- *
- * The Guest keeps page tables, but we maintain the actual ones here: these are
- * called "shadow" page tables.  Which is a very Guest-centric name: these are
- * the real page tables the CPU uses, although we keep them up to date to
- * reflect the Guest's.  (See what I mean about weird naming?  Since when do
- * shadows reflect anything?)
- *
- * Anyway, this is the most complicated part of the Host code.  There are seven
- * parts to this:
- *  (i) Looking up a page table entry when the Guest faults,
- *  (ii) Making sure the Guest stack is mapped,
- *  (iii) Setting up a page table entry when the Guest tells us one has changed,
- *  (iv) Switching page tables,
- *  (v) Flushing (throwing away) page tables,
- *  (vi) Mapping the Switcher when the Guest is about to run,
- *  (vii) Setting up the page tables initially.
-:*/
-
-/*
- * The Switcher uses the complete top PTE page.  That's 1024 PTE entries (4MB)
- * or 512 PTE entries with PAE (2MB).
- */
-#define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1)
-
-/*
- * For PAE we need the PMD index as well. We use the last 2MB, so we
- * will need the last pmd entry of the last pmd page.
- */
-#ifdef CONFIG_X86_PAE
-#define CHECK_GPGD_MASK		_PAGE_PRESENT
-#else
-#define CHECK_GPGD_MASK		_PAGE_TABLE
-#endif
-
-/*H:320
- * The page table code is curly enough to need helper functions to keep it
- * clear and clean.  The kernel itself provides many of them; one advantage
- * of insisting that the Guest and Host use the same CONFIG_X86_PAE setting.
- *
- * There are two functions which return pointers to the shadow (aka "real")
- * page tables.
- *
- * spgd_addr() takes the virtual address and returns a pointer to the top-level
- * page directory entry (PGD) for that address.  Since we keep track of several
- * page tables, the "i" argument tells us which one we're interested in (it's
- * usually the current one).
- */
-static pgd_t *spgd_addr(struct lg_cpu *cpu, u32 i, unsigned long vaddr)
-{
-	unsigned int index = pgd_index(vaddr);
-
-	/* Return a pointer index'th pgd entry for the i'th page table. */
-	return &cpu->lg->pgdirs[i].pgdir[index];
-}
-
-#ifdef CONFIG_X86_PAE
-/*
- * This routine then takes the PGD entry given above, which contains the
- * address of the PMD page.  It then returns a pointer to the PMD entry for the
- * given address.
- */
-static pmd_t *spmd_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
-{
-	unsigned int index = pmd_index(vaddr);
-	pmd_t *page;
-
-	/* You should never call this if the PGD entry wasn't valid */
-	BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
-	page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
-
-	return &page[index];
-}
-#endif
-
-/*
- * This routine then takes the page directory entry returned above, which
- * contains the address of the page table entry (PTE) page.  It then returns a
- * pointer to the PTE entry for the given address.
- */
-static pte_t *spte_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
-{
-#ifdef CONFIG_X86_PAE
-	pmd_t *pmd = spmd_addr(cpu, spgd, vaddr);
-	pte_t *page = __va(pmd_pfn(*pmd) << PAGE_SHIFT);
-
-	/* You should never call this if the PMD entry wasn't valid */
-	BUG_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT));
-#else
-	pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
-	/* You should never call this if the PGD entry wasn't valid */
-	BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
-#endif
-
-	return &page[pte_index(vaddr)];
-}
-
-/*
- * These functions are just like the above, except they access the Guest
- * page tables.  Hence they return a Guest address.
- */
-static unsigned long gpgd_addr(struct lg_cpu *cpu, unsigned long vaddr)
-{
-	unsigned int index = vaddr >> (PGDIR_SHIFT);
-	return cpu->lg->pgdirs[cpu->cpu_pgd].gpgdir + index * sizeof(pgd_t);
-}
-
-#ifdef CONFIG_X86_PAE
-/* Follow the PGD to the PMD. */
-static unsigned long gpmd_addr(pgd_t gpgd, unsigned long vaddr)
-{
-	unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
-	BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
-	return gpage + pmd_index(vaddr) * sizeof(pmd_t);
-}
-
-/* Follow the PMD to the PTE. */
-static unsigned long gpte_addr(struct lg_cpu *cpu,
-			       pmd_t gpmd, unsigned long vaddr)
-{
-	unsigned long gpage = pmd_pfn(gpmd) << PAGE_SHIFT;
-
-	BUG_ON(!(pmd_flags(gpmd) & _PAGE_PRESENT));
-	return gpage + pte_index(vaddr) * sizeof(pte_t);
-}
-#else
-/* Follow the PGD to the PTE (no mid-level for !PAE). */
-static unsigned long gpte_addr(struct lg_cpu *cpu,
-				pgd_t gpgd, unsigned long vaddr)
-{
-	unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
-
-	BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
-	return gpage + pte_index(vaddr) * sizeof(pte_t);
-}
-#endif
-/*:*/
-
-/*M:007
- * get_pfn is slow: we could probably try to grab batches of pages here as
- * an optimization (ie. pre-faulting).
-:*/
-
-/*H:350
- * This routine takes a page number given by the Guest and converts it to
- * an actual, physical page number.  It can fail for several reasons: the
- * virtual address might not be mapped by the Launcher, the write flag is set
- * and the page is read-only, or the write flag was set and the page was
- * shared so had to be copied, but we ran out of memory.
- *
- * This holds a reference to the page, so release_pte() is careful to put that
- * back.
- */
-static unsigned long get_pfn(unsigned long virtpfn, int write)
-{
-	struct page *page;
-
-	/* gup me one page at this address please! */
-	if (get_user_pages_fast(virtpfn << PAGE_SHIFT, 1, write, &page) == 1)
-		return page_to_pfn(page);
-
-	/* This value indicates failure. */
-	return -1UL;
-}
-
-/*H:340
- * Converting a Guest page table entry to a shadow (ie. real) page table
- * entry can be a little tricky.  The flags are (almost) the same, but the
- * Guest PTE contains a virtual page number: the CPU needs the real page
- * number.
- */
-static pte_t gpte_to_spte(struct lg_cpu *cpu, pte_t gpte, int write)
-{
-	unsigned long pfn, base, flags;
-
-	/*
-	 * The Guest sets the global flag, because it thinks that it is using
-	 * PGE.  We only told it to use PGE so it would tell us whether it was
-	 * flushing a kernel mapping or a userspace mapping.  We don't actually
-	 * use the global bit, so throw it away.
-	 */
-	flags = (pte_flags(gpte) & ~_PAGE_GLOBAL);
-
-	/* The Guest's pages are offset inside the Launcher. */
-	base = (unsigned long)cpu->lg->mem_base / PAGE_SIZE;
-
-	/*
-	 * We need a temporary "unsigned long" variable to hold the answer from
-	 * get_pfn(), because it returns 0xFFFFFFFF on failure, which wouldn't
-	 * fit in spte.pfn.  get_pfn() finds the real physical number of the
-	 * page, given the virtual number.
-	 */
-	pfn = get_pfn(base + pte_pfn(gpte), write);
-	if (pfn == -1UL) {
-		kill_guest(cpu, "failed to get page %lu", pte_pfn(gpte));
-		/*
-		 * When we destroy the Guest, we'll go through the shadow page
-		 * tables and release_pte() them.  Make sure we don't think
-		 * this one is valid!
-		 */
-		flags = 0;
-	}
-	/* Now we assemble our shadow PTE from the page number and flags. */
-	return pfn_pte(pfn, __pgprot(flags));
-}
-
-/*H:460 And to complete the chain, release_pte() looks like this: */
-static void release_pte(pte_t pte)
-{
-	/*
-	 * Remember that get_user_pages_fast() took a reference to the page, in
-	 * get_pfn()?  We have to put it back now.
-	 */
-	if (pte_flags(pte) & _PAGE_PRESENT)
-		put_page(pte_page(pte));
-}
-/*:*/
-
-static bool gpte_in_iomem(struct lg_cpu *cpu, pte_t gpte)
-{
-	/* We don't handle large pages. */
-	if (pte_flags(gpte) & _PAGE_PSE)
-		return false;
-
-	return (pte_pfn(gpte) >= cpu->lg->pfn_limit
-		&& pte_pfn(gpte) < cpu->lg->device_limit);
-}
-
-static bool check_gpte(struct lg_cpu *cpu, pte_t gpte)
-{
-	if ((pte_flags(gpte) & _PAGE_PSE) ||
-	    pte_pfn(gpte) >= cpu->lg->pfn_limit) {
-		kill_guest(cpu, "bad page table entry");
-		return false;
-	}
-	return true;
-}
-
-static bool check_gpgd(struct lg_cpu *cpu, pgd_t gpgd)
-{
-	if ((pgd_flags(gpgd) & ~CHECK_GPGD_MASK) ||
-	    (pgd_pfn(gpgd) >= cpu->lg->pfn_limit)) {
-		kill_guest(cpu, "bad page directory entry");
-		return false;
-	}
-	return true;
-}
-
-#ifdef CONFIG_X86_PAE
-static bool check_gpmd(struct lg_cpu *cpu, pmd_t gpmd)
-{
-	if ((pmd_flags(gpmd) & ~_PAGE_TABLE) ||
-	    (pmd_pfn(gpmd) >= cpu->lg->pfn_limit)) {
-		kill_guest(cpu, "bad page middle directory entry");
-		return false;
-	}
-	return true;
-}
-#endif
-
-/*H:331
- * This is the core routine to walk the shadow page tables and find the page
- * table entry for a specific address.
- *
- * If allocate is set, then we allocate any missing levels, setting the flags
- * on the new page directory and mid-level directories using the arguments
- * (which are copied from the Guest's page table entries).
- */
-static pte_t *find_spte(struct lg_cpu *cpu, unsigned long vaddr, bool allocate,
-			int pgd_flags, int pmd_flags)
-{
-	pgd_t *spgd;
-	/* Mid level for PAE. */
-#ifdef CONFIG_X86_PAE
-	pmd_t *spmd;
-#endif
-
-	/* Get top level entry. */
-	spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr);
-	if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) {
-		/* No shadow entry: allocate a new shadow PTE page. */
-		unsigned long ptepage;
-
-		/* If they didn't want us to allocate anything, stop. */
-		if (!allocate)
-			return NULL;
-
-		ptepage = get_zeroed_page(GFP_KERNEL);
-		/*
-		 * This is not really the Guest's fault, but killing it is
-		 * simple for this corner case.
-		 */
-		if (!ptepage) {
-			kill_guest(cpu, "out of memory allocating pte page");
-			return NULL;
-		}
-		/*
-		 * And we copy the flags to the shadow PGD entry.  The page
-		 * number in the shadow PGD is the page we just allocated.
-		 */
-		set_pgd(spgd, __pgd(__pa(ptepage) | pgd_flags));
-	}
-
-	/*
-	 * Intel's Physical Address Extension actually uses three levels of
-	 * page tables, so we need to look in the mid-level.
-	 */
-#ifdef CONFIG_X86_PAE
-	/* Now look at the mid-level shadow entry. */
-	spmd = spmd_addr(cpu, *spgd, vaddr);
-
-	if (!(pmd_flags(*spmd) & _PAGE_PRESENT)) {
-		/* No shadow entry: allocate a new shadow PTE page. */
-		unsigned long ptepage;
-
-		/* If they didn't want us to allocate anything, stop. */
-		if (!allocate)
-			return NULL;
-
-		ptepage = get_zeroed_page(GFP_KERNEL);
-
-		/*
-		 * This is not really the Guest's fault, but killing it is
-		 * simple for this corner case.
-		 */
-		if (!ptepage) {
-			kill_guest(cpu, "out of memory allocating pmd page");
-			return NULL;
-		}
-
-		/*
-		 * And we copy the flags to the shadow PMD entry.  The page
-		 * number in the shadow PMD is the page we just allocated.
-		 */
-		set_pmd(spmd, __pmd(__pa(ptepage) | pmd_flags));
-	}
-#endif
-
-	/* Get the pointer to the shadow PTE entry we're going to set. */
-	return spte_addr(cpu, *spgd, vaddr);
-}
-
-/*H:330
- * (i) Looking up a page table entry when the Guest faults.
- *
- * We saw this call in run_guest(): when we see a page fault in the Guest, we
- * come here.  That's because we only set up the shadow page tables lazily as
- * they're needed, so we get page faults all the time and quietly fix them up
- * and return to the Guest without it knowing.
- *
- * If we fixed up the fault (ie. we mapped the address), this routine returns
- * true.  Otherwise, it was a real fault and we need to tell the Guest.
- *
- * There's a corner case: they're trying to access memory between
- * pfn_limit and device_limit, which is I/O memory.  In this case, we
- * return false and set @iomem to the physical address, so the the
- * Launcher can handle the instruction manually.
- */
-bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode,
-		 unsigned long *iomem)
-{
-	unsigned long gpte_ptr;
-	pte_t gpte;
-	pte_t *spte;
-	pmd_t gpmd;
-	pgd_t gpgd;
-
-	*iomem = 0;
-
-	/* We never demand page the Switcher, so trying is a mistake. */
-	if (vaddr >= switcher_addr)
-		return false;
-
-	/* First step: get the top-level Guest page table entry. */
-	if (unlikely(cpu->linear_pages)) {
-		/* Faking up a linear mapping. */
-		gpgd = __pgd(CHECK_GPGD_MASK);
-	} else {
-		gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
-		/* Toplevel not present?  We can't map it in. */
-		if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
-			return false;
-
-		/* 
-		 * This kills the Guest if it has weird flags or tries to
-		 * refer to a "physical" address outside the bounds.
-		 */
-		if (!check_gpgd(cpu, gpgd))
-			return false;
-	}
-
-	/* This "mid-level" entry is only used for non-linear, PAE mode. */
-	gpmd = __pmd(_PAGE_TABLE);
-
-#ifdef CONFIG_X86_PAE
-	if (likely(!cpu->linear_pages)) {
-		gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
-		/* Middle level not present?  We can't map it in. */
-		if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
-			return false;
-
-		/* 
-		 * This kills the Guest if it has weird flags or tries to
-		 * refer to a "physical" address outside the bounds.
-		 */
-		if (!check_gpmd(cpu, gpmd))
-			return false;
-	}
-
-	/*
-	 * OK, now we look at the lower level in the Guest page table: keep its
-	 * address, because we might update it later.
-	 */
-	gpte_ptr = gpte_addr(cpu, gpmd, vaddr);
-#else
-	/*
-	 * OK, now we look at the lower level in the Guest page table: keep its
-	 * address, because we might update it later.
-	 */
-	gpte_ptr = gpte_addr(cpu, gpgd, vaddr);
-#endif
-
-	if (unlikely(cpu->linear_pages)) {
-		/* Linear?  Make up a PTE which points to same page. */
-		gpte = __pte((vaddr & PAGE_MASK) | _PAGE_RW | _PAGE_PRESENT);
-	} else {
-		/* Read the actual PTE value. */
-		gpte = lgread(cpu, gpte_ptr, pte_t);
-	}
-
-	/* If this page isn't in the Guest page tables, we can't page it in. */
-	if (!(pte_flags(gpte) & _PAGE_PRESENT))
-		return false;
-
-	/*
-	 * Check they're not trying to write to a page the Guest wants
-	 * read-only (bit 2 of errcode == write).
-	 */
-	if ((errcode & 2) && !(pte_flags(gpte) & _PAGE_RW))
-		return false;
-
-	/* User access to a kernel-only page? (bit 3 == user access) */
-	if ((errcode & 4) && !(pte_flags(gpte) & _PAGE_USER))
-		return false;
-
-	/* If they're accessing io memory, we expect a fault. */
-	if (gpte_in_iomem(cpu, gpte)) {
-		*iomem = (pte_pfn(gpte) << PAGE_SHIFT) | (vaddr & ~PAGE_MASK);
-		return false;
-	}
-
-	/*
-	 * Check that the Guest PTE flags are OK, and the page number is below
-	 * the pfn_limit (ie. not mapping the Launcher binary).
-	 */
-	if (!check_gpte(cpu, gpte))
-		return false;
-
-	/* Add the _PAGE_ACCESSED and (for a write) _PAGE_DIRTY flag */
-	gpte = pte_mkyoung(gpte);
-	if (errcode & 2)
-		gpte = pte_mkdirty(gpte);
-
-	/* Get the pointer to the shadow PTE entry we're going to set. */
-	spte = find_spte(cpu, vaddr, true, pgd_flags(gpgd), pmd_flags(gpmd));
-	if (!spte)
-		return false;
-
-	/*
-	 * If there was a valid shadow PTE entry here before, we release it.
-	 * This can happen with a write to a previously read-only entry.
-	 */
-	release_pte(*spte);
-
-	/*
-	 * If this is a write, we insist that the Guest page is writable (the
-	 * final arg to gpte_to_spte()).
-	 */
-	if (pte_dirty(gpte))
-		*spte = gpte_to_spte(cpu, gpte, 1);
-	else
-		/*
-		 * If this is a read, don't set the "writable" bit in the page
-		 * table entry, even if the Guest says it's writable.  That way
-		 * we will come back here when a write does actually occur, so
-		 * we can update the Guest's _PAGE_DIRTY flag.
-		 */
-		set_pte(spte, gpte_to_spte(cpu, pte_wrprotect(gpte), 0));
-
-	/*
-	 * Finally, we write the Guest PTE entry back: we've set the
-	 * _PAGE_ACCESSED and maybe the _PAGE_DIRTY flags.
-	 */
-	if (likely(!cpu->linear_pages))
-		lgwrite(cpu, gpte_ptr, pte_t, gpte);
-
-	/*
-	 * The fault is fixed, the page table is populated, the mapping
-	 * manipulated, the result returned and the code complete.  A small
-	 * delay and a trace of alliteration are the only indications the Guest
-	 * has that a page fault occurred at all.
-	 */
-	return true;
-}
-
-/*H:360
- * (ii) Making sure the Guest stack is mapped.
- *
- * Remember that direct traps into the Guest need a mapped Guest kernel stack.
- * pin_stack_pages() calls us here: we could simply call demand_page(), but as
- * we've seen that logic is quite long, and usually the stack pages are already
- * mapped, so it's overkill.
- *
- * This is a quick version which answers the question: is this virtual address
- * mapped by the shadow page tables, and is it writable?
- */
-static bool page_writable(struct lg_cpu *cpu, unsigned long vaddr)
-{
-	pte_t *spte;
-	unsigned long flags;
-
-	/* You can't put your stack in the Switcher! */
-	if (vaddr >= switcher_addr)
-		return false;
-
-	/* If there's no shadow PTE, it's not writable. */
-	spte = find_spte(cpu, vaddr, false, 0, 0);
-	if (!spte)
-		return false;
-
-	/*
-	 * Check the flags on the pte entry itself: it must be present and
-	 * writable.
-	 */
-	flags = pte_flags(*spte);
-	return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW);
-}
-
-/*
- * So, when pin_stack_pages() asks us to pin a page, we check if it's already
- * in the page tables, and if not, we call demand_page() with error code 2
- * (meaning "write").
- */
-void pin_page(struct lg_cpu *cpu, unsigned long vaddr)
-{
-	unsigned long iomem;
-
-	if (!page_writable(cpu, vaddr) && !demand_page(cpu, vaddr, 2, &iomem))
-		kill_guest(cpu, "bad stack page %#lx", vaddr);
-}
-/*:*/
-
-#ifdef CONFIG_X86_PAE
-static void release_pmd(pmd_t *spmd)
-{
-	/* If the entry's not present, there's nothing to release. */
-	if (pmd_flags(*spmd) & _PAGE_PRESENT) {
-		unsigned int i;
-		pte_t *ptepage = __va(pmd_pfn(*spmd) << PAGE_SHIFT);
-		/* For each entry in the page, we might need to release it. */
-		for (i = 0; i < PTRS_PER_PTE; i++)
-			release_pte(ptepage[i]);
-		/* Now we can free the page of PTEs */
-		free_page((long)ptepage);
-		/* And zero out the PMD entry so we never release it twice. */
-		set_pmd(spmd, __pmd(0));
-	}
-}
-
-static void release_pgd(pgd_t *spgd)
-{
-	/* If the entry's not present, there's nothing to release. */
-	if (pgd_flags(*spgd) & _PAGE_PRESENT) {
-		unsigned int i;
-		pmd_t *pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
-
-		for (i = 0; i < PTRS_PER_PMD; i++)
-			release_pmd(&pmdpage[i]);
-
-		/* Now we can free the page of PMDs */
-		free_page((long)pmdpage);
-		/* And zero out the PGD entry so we never release it twice. */
-		set_pgd(spgd, __pgd(0));
-	}
-}
-
-#else /* !CONFIG_X86_PAE */
-/*H:450
- * If we chase down the release_pgd() code, the non-PAE version looks like
- * this.  The PAE version is almost identical, but instead of calling
- * release_pte it calls release_pmd(), which looks much like this.
- */
-static void release_pgd(pgd_t *spgd)
-{
-	/* If the entry's not present, there's nothing to release. */
-	if (pgd_flags(*spgd) & _PAGE_PRESENT) {
-		unsigned int i;
-		/*
-		 * Converting the pfn to find the actual PTE page is easy: turn
-		 * the page number into a physical address, then convert to a
-		 * virtual address (easy for kernel pages like this one).
-		 */
-		pte_t *ptepage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
-		/* For each entry in the page, we might need to release it. */
-		for (i = 0; i < PTRS_PER_PTE; i++)
-			release_pte(ptepage[i]);
-		/* Now we can free the page of PTEs */
-		free_page((long)ptepage);
-		/* And zero out the PGD entry so we never release it twice. */
-		*spgd = __pgd(0);
-	}
-}
-#endif
-
-/*H:445
- * We saw flush_user_mappings() twice: once from the flush_user_mappings()
- * hypercall and once in new_pgdir() when we re-used a top-level pgdir page.
- * It simply releases every PTE page from 0 up to the Guest's kernel address.
- */
-static void flush_user_mappings(struct lguest *lg, int idx)
-{
-	unsigned int i;
-	/* Release every pgd entry up to the kernel's address. */
-	for (i = 0; i < pgd_index(lg->kernel_address); i++)
-		release_pgd(lg->pgdirs[idx].pgdir + i);
-}
-
-/*H:440
- * (v) Flushing (throwing away) page tables,
- *
- * The Guest has a hypercall to throw away the page tables: it's used when a
- * large number of mappings have been changed.
- */
-void guest_pagetable_flush_user(struct lg_cpu *cpu)
-{
-	/* Drop the userspace part of the current page table. */
-	flush_user_mappings(cpu->lg, cpu->cpu_pgd);
-}
-/*:*/
-
-/* We walk down the guest page tables to get a guest-physical address */
-bool __guest_pa(struct lg_cpu *cpu, unsigned long vaddr, unsigned long *paddr)
-{
-	pgd_t gpgd;
-	pte_t gpte;
-#ifdef CONFIG_X86_PAE
-	pmd_t gpmd;
-#endif
-
-	/* Still not set up?  Just map 1:1. */
-	if (unlikely(cpu->linear_pages)) {
-		*paddr = vaddr;
-		return true;
-	}
-
-	/* First step: get the top-level Guest page table entry. */
-	gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
-	/* Toplevel not present?  We can't map it in. */
-	if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
-		goto fail;
-
-#ifdef CONFIG_X86_PAE
-	gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
-	if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
-		goto fail;
-	gpte = lgread(cpu, gpte_addr(cpu, gpmd, vaddr), pte_t);
-#else
-	gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);
-#endif
-	if (!(pte_flags(gpte) & _PAGE_PRESENT))
-		goto fail;
-
-	*paddr = pte_pfn(gpte) * PAGE_SIZE | (vaddr & ~PAGE_MASK);
-	return true;
-
-fail:
-	*paddr = -1UL;
-	return false;
-}
-
-/*
- * This is the version we normally use: kills the Guest if it uses a
- * bad address
- */
-unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
-{
-	unsigned long paddr;
-
-	if (!__guest_pa(cpu, vaddr, &paddr))
-		kill_guest(cpu, "Bad address %#lx", vaddr);
-	return paddr;
-}
-
-/*
- * We keep several page tables.  This is a simple routine to find the page
- * table (if any) corresponding to this top-level address the Guest has given
- * us.
- */
-static unsigned int find_pgdir(struct lguest *lg, unsigned long pgtable)
-{
-	unsigned int i;
-	for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
-		if (lg->pgdirs[i].pgdir && lg->pgdirs[i].gpgdir == pgtable)
-			break;
-	return i;
-}
-
-/*H:435
- * And this is us, creating the new page directory.  If we really do
- * allocate a new one (and so the kernel parts are not there), we set
- * blank_pgdir.
- */
-static unsigned int new_pgdir(struct lg_cpu *cpu,
-			      unsigned long gpgdir,
-			      int *blank_pgdir)
-{
-	unsigned int next;
-
-	/*
-	 * We pick one entry at random to throw out.  Choosing the Least
-	 * Recently Used might be better, but this is easy.
-	 */
-	next = prandom_u32() % ARRAY_SIZE(cpu->lg->pgdirs);
-	/* If it's never been allocated at all before, try now. */
-	if (!cpu->lg->pgdirs[next].pgdir) {
-		cpu->lg->pgdirs[next].pgdir =
-					(pgd_t *)get_zeroed_page(GFP_KERNEL);
-		/* If the allocation fails, just keep using the one we have */
-		if (!cpu->lg->pgdirs[next].pgdir)
-			next = cpu->cpu_pgd;
-		else {
-			/*
-			 * This is a blank page, so there are no kernel
-			 * mappings: caller must map the stack!
-			 */
-			*blank_pgdir = 1;
-		}
-	}
-	/* Record which Guest toplevel this shadows. */
-	cpu->lg->pgdirs[next].gpgdir = gpgdir;
-	/* Release all the non-kernel mappings. */
-	flush_user_mappings(cpu->lg, next);
-
-	/* This hasn't run on any CPU at all. */
-	cpu->lg->pgdirs[next].last_host_cpu = -1;
-
-	return next;
-}
-
-/*H:501
- * We do need the Switcher code mapped at all times, so we allocate that
- * part of the Guest page table here.  We map the Switcher code immediately,
- * but defer mapping of the guest register page and IDT/LDT etc page until
- * just before we run the guest in map_switcher_in_guest().
- *
- * We *could* do this setup in map_switcher_in_guest(), but at that point
- * we've interrupts disabled, and allocating pages like that is fraught: we
- * can't sleep if we need to free up some memory.
- */
-static bool allocate_switcher_mapping(struct lg_cpu *cpu)
-{
-	int i;
-
-	for (i = 0; i < TOTAL_SWITCHER_PAGES; i++) {
-		pte_t *pte = find_spte(cpu, switcher_addr + i * PAGE_SIZE, true,
-				       CHECK_GPGD_MASK, _PAGE_TABLE);
-		if (!pte)
-			return false;
-
-		/*
-		 * Map the switcher page if not already there.  It might
-		 * already be there because we call allocate_switcher_mapping()
-		 * in guest_set_pgd() just in case it did discard our Switcher
-		 * mapping, but it probably didn't.
-		 */
-		if (i == 0 && !(pte_flags(*pte) & _PAGE_PRESENT)) {
-			/* Get a reference to the Switcher page. */
-			get_page(lg_switcher_pages[0]);
-			/* Create a read-only, exectuable, kernel-style PTE */
-			set_pte(pte,
-				mk_pte(lg_switcher_pages[0], PAGE_KERNEL_RX));
-		}
-	}
-	cpu->lg->pgdirs[cpu->cpu_pgd].switcher_mapped = true;
-	return true;
-}
-
-/*H:470
- * Finally, a routine which throws away everything: all PGD entries in all
- * the shadow page tables, including the Guest's kernel mappings.  This is used
- * when we destroy the Guest.
- */
-static void release_all_pagetables(struct lguest *lg)
-{
-	unsigned int i, j;
-
-	/* Every shadow pagetable this Guest has */
-	for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++) {
-		if (!lg->pgdirs[i].pgdir)
-			continue;
-
-		/* Every PGD entry. */
-		for (j = 0; j < PTRS_PER_PGD; j++)
-			release_pgd(lg->pgdirs[i].pgdir + j);
-		lg->pgdirs[i].switcher_mapped = false;
-		lg->pgdirs[i].last_host_cpu = -1;
-	}
-}
-
-/*
- * We also throw away everything when a Guest tells us it's changed a kernel
- * mapping.  Since kernel mappings are in every page table, it's easiest to
- * throw them all away.  This traps the Guest in amber for a while as
- * everything faults back in, but it's rare.
- */
-void guest_pagetable_clear_all(struct lg_cpu *cpu)
-{
-	release_all_pagetables(cpu->lg);
-	/* We need the Guest kernel stack mapped again. */
-	pin_stack_pages(cpu);
-	/* And we need Switcher allocated. */
-	if (!allocate_switcher_mapping(cpu))
-		kill_guest(cpu, "Cannot populate switcher mapping");
-}
-
-/*H:430
- * (iv) Switching page tables
- *
- * Now we've seen all the page table setting and manipulation, let's see
- * what happens when the Guest changes page tables (ie. changes the top-level
- * pgdir).  This occurs on almost every context switch.
- */
-void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable)
-{
-	int newpgdir, repin = 0;
-
-	/*
-	 * The very first time they call this, we're actually running without
-	 * any page tables; we've been making it up.  Throw them away now.
-	 */
-	if (unlikely(cpu->linear_pages)) {
-		release_all_pagetables(cpu->lg);
-		cpu->linear_pages = false;
-		/* Force allocation of a new pgdir. */
-		newpgdir = ARRAY_SIZE(cpu->lg->pgdirs);
-	} else {
-		/* Look to see if we have this one already. */
-		newpgdir = find_pgdir(cpu->lg, pgtable);
-	}
-
-	/*
-	 * If not, we allocate or mug an existing one: if it's a fresh one,
-	 * repin gets set to 1.
-	 */
-	if (newpgdir == ARRAY_SIZE(cpu->lg->pgdirs))
-		newpgdir = new_pgdir(cpu, pgtable, &repin);
-	/* Change the current pgd index to the new one. */
-	cpu->cpu_pgd = newpgdir;
-	/*
-	 * If it was completely blank, we map in the Guest kernel stack and
-	 * the Switcher.
-	 */
-	if (repin)
-		pin_stack_pages(cpu);
-
-	if (!cpu->lg->pgdirs[cpu->cpu_pgd].switcher_mapped) {
-		if (!allocate_switcher_mapping(cpu))
-			kill_guest(cpu, "Cannot populate switcher mapping");
-	}
-}
-/*:*/
-
-/*M:009
- * Since we throw away all mappings when a kernel mapping changes, our
- * performance sucks for guests using highmem.  In fact, a guest with
- * PAGE_OFFSET 0xc0000000 (the default) and more than about 700MB of RAM is
- * usually slower than a Guest with less memory.
- *
- * This, of course, cannot be fixed.  It would take some kind of... well, I
- * don't know, but the term "puissant code-fu" comes to mind.
-:*/
-
-/*H:420
- * This is the routine which actually sets the page table entry for then
- * "idx"'th shadow page table.
- *
- * Normally, we can just throw out the old entry and replace it with 0: if they
- * use it demand_page() will put the new entry in.  We need to do this anyway:
- * The Guest expects _PAGE_ACCESSED to be set on its PTE the first time a page
- * is read from, and _PAGE_DIRTY when it's written to.
- *
- * But Avi Kivity pointed out that most Operating Systems (Linux included) set
- * these bits on PTEs immediately anyway.  This is done to save the CPU from
- * having to update them, but it helps us the same way: if they set
- * _PAGE_ACCESSED then we can put a read-only PTE entry in immediately, and if
- * they set _PAGE_DIRTY then we can put a writable PTE entry in immediately.
- */
-static void __guest_set_pte(struct lg_cpu *cpu, int idx,
-		       unsigned long vaddr, pte_t gpte)
-{
-	/* Look up the matching shadow page directory entry. */
-	pgd_t *spgd = spgd_addr(cpu, idx, vaddr);
-#ifdef CONFIG_X86_PAE
-	pmd_t *spmd;
-#endif
-
-	/* If the top level isn't present, there's no entry to update. */
-	if (pgd_flags(*spgd) & _PAGE_PRESENT) {
-#ifdef CONFIG_X86_PAE
-		spmd = spmd_addr(cpu, *spgd, vaddr);
-		if (pmd_flags(*spmd) & _PAGE_PRESENT) {
-#endif
-			/* Otherwise, start by releasing the existing entry. */
-			pte_t *spte = spte_addr(cpu, *spgd, vaddr);
-			release_pte(*spte);
-
-			/*
-			 * If they're setting this entry as dirty or accessed,
-			 * we might as well put that entry they've given us in
-			 * now.  This shaves 10% off a copy-on-write
-			 * micro-benchmark.
-			 */
-			if ((pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED))
-			    && !gpte_in_iomem(cpu, gpte)) {
-				if (!check_gpte(cpu, gpte))
-					return;
-				set_pte(spte,
-					gpte_to_spte(cpu, gpte,
-						pte_flags(gpte) & _PAGE_DIRTY));
-			} else {
-				/*
-				 * Otherwise kill it and we can demand_page()
-				 * it in later.
-				 */
-				set_pte(spte, __pte(0));
-			}
-#ifdef CONFIG_X86_PAE
-		}
-#endif
-	}
-}
-
-/*H:410
- * Updating a PTE entry is a little trickier.
- *
- * We keep track of several different page tables (the Guest uses one for each
- * process, so it makes sense to cache at least a few).  Each of these have
- * identical kernel parts: ie. every mapping above PAGE_OFFSET is the same for
- * all processes.  So when the page table above that address changes, we update
- * all the page tables, not just the current one.  This is rare.
- *
- * The benefit is that when we have to track a new page table, we can keep all
- * the kernel mappings.  This speeds up context switch immensely.
- */
-void guest_set_pte(struct lg_cpu *cpu,
-		   unsigned long gpgdir, unsigned long vaddr, pte_t gpte)
-{
-	/* We don't let you remap the Switcher; we need it to get back! */
-	if (vaddr >= switcher_addr) {
-		kill_guest(cpu, "attempt to set pte into Switcher pages");
-		return;
-	}
-
-	/*
-	 * Kernel mappings must be changed on all top levels.  Slow, but doesn't
-	 * happen often.
-	 */
-	if (vaddr >= cpu->lg->kernel_address) {
-		unsigned int i;
-		for (i = 0; i < ARRAY_SIZE(cpu->lg->pgdirs); i++)
-			if (cpu->lg->pgdirs[i].pgdir)
-				__guest_set_pte(cpu, i, vaddr, gpte);
-	} else {
-		/* Is this page table one we have a shadow for? */
-		int pgdir = find_pgdir(cpu->lg, gpgdir);
-		if (pgdir != ARRAY_SIZE(cpu->lg->pgdirs))
-			/* If so, do the update. */
-			__guest_set_pte(cpu, pgdir, vaddr, gpte);
-	}
-}
-
-/*H:400
- * (iii) Setting up a page table entry when the Guest tells us one has changed.
- *
- * Just like we did in interrupts_and_traps.c, it makes sense for us to deal
- * with the other side of page tables while we're here: what happens when the
- * Guest asks for a page table to be updated?
- *
- * We already saw that demand_page() will fill in the shadow page tables when
- * needed, so we can simply remove shadow page table entries whenever the Guest
- * tells us they've changed.  When the Guest tries to use the new entry it will
- * fault and demand_page() will fix it up.
- *
- * So with that in mind here's our code to update a (top-level) PGD entry:
- */
-void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
-{
-	int pgdir;
-
-	if (idx > PTRS_PER_PGD) {
-		kill_guest(&lg->cpus[0], "Attempt to set pgd %u/%u",
-			   idx, PTRS_PER_PGD);
-		return;
-	}
-
-	/* If they're talking about a page table we have a shadow for... */
-	pgdir = find_pgdir(lg, gpgdir);
-	if (pgdir < ARRAY_SIZE(lg->pgdirs)) {
-		/* ... throw it away. */
-		release_pgd(lg->pgdirs[pgdir].pgdir + idx);
-		/* That might have been the Switcher mapping, remap it. */
-		if (!allocate_switcher_mapping(&lg->cpus[0])) {
-			kill_guest(&lg->cpus[0],
-				   "Cannot populate switcher mapping");
-		}
-		lg->pgdirs[pgdir].last_host_cpu = -1;
-	}
-}
-
-#ifdef CONFIG_X86_PAE
-/* For setting a mid-level, we just throw everything away.  It's easy. */
-void guest_set_pmd(struct lguest *lg, unsigned long pmdp, u32 idx)
-{
-	guest_pagetable_clear_all(&lg->cpus[0]);
-}
-#endif
-
-/*H:500
- * (vii) Setting up the page tables initially.
- *
- * When a Guest is first created, set initialize a shadow page table which
- * we will populate on future faults.  The Guest doesn't have any actual
- * pagetables yet, so we set linear_pages to tell demand_page() to fake it
- * for the moment.
- *
- * We do need the Switcher to be mapped at all times, so we allocate that
- * part of the Guest page table here.
- */
-int init_guest_pagetable(struct lguest *lg)
-{
-	struct lg_cpu *cpu = &lg->cpus[0];
-	int allocated = 0;
-
-	/* lg (and lg->cpus[]) starts zeroed: this allocates a new pgdir */
-	cpu->cpu_pgd = new_pgdir(cpu, 0, &allocated);
-	if (!allocated)
-		return -ENOMEM;
-
-	/* We start with a linear mapping until the initialize. */
-	cpu->linear_pages = true;
-
-	/* Allocate the page tables for the Switcher. */
-	if (!allocate_switcher_mapping(cpu)) {
-		release_all_pagetables(lg);
-		return -ENOMEM;
-	}
-
-	return 0;
-}
-
-/*H:508 When the Guest calls LHCALL_LGUEST_INIT we do more setup. */
-void page_table_guest_data_init(struct lg_cpu *cpu)
-{
-	/*
-	 * We tell the Guest that it can't use the virtual addresses
-	 * used by the Switcher.  This trick is equivalent to 4GB -
-	 * switcher_addr.
-	 */
-	u32 top = ~switcher_addr + 1;
-
-	/* We get the kernel address: above this is all kernel memory. */
-	if (get_user(cpu->lg->kernel_address,
-		     &cpu->lg->lguest_data->kernel_address)
-		/*
-		 * We tell the Guest that it can't use the top virtual
-		 * addresses (used by the Switcher).
-		 */
-	    || put_user(top, &cpu->lg->lguest_data->reserve_mem)) {
-		kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
-		return;
-	}
-
-	/*
-	 * In flush_user_mappings() we loop from 0 to
-	 * "pgd_index(lg->kernel_address)".  This assumes it won't hit the
-	 * Switcher mappings, so check that now.
-	 */
-	if (cpu->lg->kernel_address >= switcher_addr)
-		kill_guest(cpu, "bad kernel address %#lx",
-				 cpu->lg->kernel_address);
-}
-
-/* When a Guest dies, our cleanup is fairly simple. */
-void free_guest_pagetable(struct lguest *lg)
-{
-	unsigned int i;
-
-	/* Throw away all page table pages. */
-	release_all_pagetables(lg);
-	/* Now free the top levels: free_page() can handle 0 just fine. */
-	for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
-		free_page((long)lg->pgdirs[i].pgdir);
-}
-
-/*H:481
- * This clears the Switcher mappings for cpu #i.
- */
-static void remove_switcher_percpu_map(struct lg_cpu *cpu, unsigned int i)
-{
-	unsigned long base = switcher_addr + PAGE_SIZE + i * PAGE_SIZE*2;
-	pte_t *pte;
-
-	/* Clear the mappings for both pages. */
-	pte = find_spte(cpu, base, false, 0, 0);
-	release_pte(*pte);
-	set_pte(pte, __pte(0));
-
-	pte = find_spte(cpu, base + PAGE_SIZE, false, 0, 0);
-	release_pte(*pte);
-	set_pte(pte, __pte(0));
-}
-
-/*H:480
- * (vi) Mapping the Switcher when the Guest is about to run.
- *
- * The Switcher and the two pages for this CPU need to be visible in the Guest
- * (and not the pages for other CPUs).
- *
- * The pages for the pagetables have all been allocated before: we just need
- * to make sure the actual PTEs are up-to-date for the CPU we're about to run
- * on.
- */
-void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages)
-{
-	unsigned long base;
-	struct page *percpu_switcher_page, *regs_page;
-	pte_t *pte;
-	struct pgdir *pgdir = &cpu->lg->pgdirs[cpu->cpu_pgd];
-
-	/* Switcher page should always be mapped by now! */
-	BUG_ON(!pgdir->switcher_mapped);
-
-	/* 
-	 * Remember that we have two pages for each Host CPU, so we can run a
-	 * Guest on each CPU without them interfering.  We need to make sure
-	 * those pages are mapped correctly in the Guest, but since we usually
-	 * run on the same CPU, we cache that, and only update the mappings
-	 * when we move.
-	 */
-	if (pgdir->last_host_cpu == raw_smp_processor_id())
-		return;
-
-	/* -1 means unknown so we remove everything. */
-	if (pgdir->last_host_cpu == -1) {
-		unsigned int i;
-		for_each_possible_cpu(i)
-			remove_switcher_percpu_map(cpu, i);
-	} else {
-		/* We know exactly what CPU mapping to remove. */
-		remove_switcher_percpu_map(cpu, pgdir->last_host_cpu);
-	}
-
-	/*
-	 * When we're running the Guest, we want the Guest's "regs" page to
-	 * appear where the first Switcher page for this CPU is.  This is an
-	 * optimization: when the Switcher saves the Guest registers, it saves
-	 * them into the first page of this CPU's "struct lguest_pages": if we
-	 * make sure the Guest's register page is already mapped there, we
-	 * don't have to copy them out again.
-	 */
-	/* Find the shadow PTE for this regs page. */
-	base = switcher_addr + PAGE_SIZE
-		+ raw_smp_processor_id() * sizeof(struct lguest_pages);
-	pte = find_spte(cpu, base, false, 0, 0);
-	regs_page = pfn_to_page(__pa(cpu->regs_page) >> PAGE_SHIFT);
-	get_page(regs_page);
-	set_pte(pte, mk_pte(regs_page, __pgprot(__PAGE_KERNEL & ~_PAGE_GLOBAL)));
-
-	/*
-	 * We map the second page of the struct lguest_pages read-only in
-	 * the Guest: the IDT, GDT and other things it's not supposed to
-	 * change.
-	 */
-	pte = find_spte(cpu, base + PAGE_SIZE, false, 0, 0);
-	percpu_switcher_page
-		= lg_switcher_pages[1 + raw_smp_processor_id()*2 + 1];
-	get_page(percpu_switcher_page);
-	set_pte(pte, mk_pte(percpu_switcher_page,
-			    __pgprot(__PAGE_KERNEL_RO & ~_PAGE_GLOBAL)));
-
-	pgdir->last_host_cpu = raw_smp_processor_id();
-}
-
-/*H:490
- * We've made it through the page table code.  Perhaps our tired brains are
- * still processing the details, or perhaps we're simply glad it's over.
- *
- * If nothing else, note that all this complexity in juggling shadow page tables
- * in sync with the Guest's page tables is for one reason: for most Guests this
- * page table dance determines how bad performance will be.  This is why Xen
- * uses exotic direct Guest pagetable manipulation, and why both Intel and AMD
- * have implemented shadow page table support directly into hardware.
- *
- * There is just one file remaining in the Host.
- */
diff --git a/drivers/lguest/segments.c b/drivers/lguest/segments.c
deleted file mode 100644
index c4fb424dfddb..000000000000
--- a/drivers/lguest/segments.c
+++ /dev/null
@@ -1,228 +0,0 @@
-/*P:600
- * The x86 architecture has segments, which involve a table of descriptors
- * which can be used to do funky things with virtual address interpretation.
- * We originally used to use segments so the Guest couldn't alter the
- * Guest<->Host Switcher, and then we had to trim Guest segments, and restore
- * for userspace per-thread segments, but trim again for on userspace->kernel
- * transitions...  This nightmarish creation was contained within this file,
- * where we knew not to tread without heavy armament and a change of underwear.
- *
- * In these modern times, the segment handling code consists of simple sanity
- * checks, and the worst you'll experience reading this code is butterfly-rash
- * from frolicking through its parklike serenity.
-:*/
-#include "lg.h"
-
-/*H:600
- * Segments & The Global Descriptor Table
- *
- * (That title sounds like a bad Nerdcore group.  Not to suggest that there are
- * any good Nerdcore groups, but in high school a friend of mine had a band
- * called Joe Fish and the Chips, so there are definitely worse band names).
- *
- * To refresh: the GDT is a table of 8-byte values describing segments.  Once
- * set up, these segments can be loaded into one of the 6 "segment registers".
- *
- * GDT entries are passed around as "struct desc_struct"s, which like IDT
- * entries are split into two 32-bit members, "a" and "b".  One day, someone
- * will clean that up, and be declared a Hero.  (No pressure, I'm just saying).
- *
- * Anyway, the GDT entry contains a base (the start address of the segment), a
- * limit (the size of the segment - 1), and some flags.  Sounds simple, and it
- * would be, except those zany Intel engineers decided that it was too boring
- * to put the base at one end, the limit at the other, and the flags in
- * between.  They decided to shotgun the bits at random throughout the 8 bytes,
- * like so:
- *
- * 0               16                     40       48  52  56     63
- * [ limit part 1 ][     base part 1     ][ flags ][li][fl][base ]
- *                                                  mit ags part 2
- *                                                part 2
- *
- * As a result, this file contains a certain amount of magic numeracy.  Let's
- * begin.
- */
-
-/*
- * There are several entries we don't let the Guest set.  The TSS entry is the
- * "Task State Segment" which controls all kinds of delicate things.  The
- * LGUEST_CS and LGUEST_DS entries are reserved for the Switcher, and the
- * the Guest can't be trusted to deal with double faults.
- */
-static bool ignored_gdt(unsigned int num)
-{
-	return (num == GDT_ENTRY_TSS
-		|| num == GDT_ENTRY_LGUEST_CS
-		|| num == GDT_ENTRY_LGUEST_DS
-		|| num == GDT_ENTRY_DOUBLEFAULT_TSS);
-}
-
-/*H:630
- * Once the Guest gave us new GDT entries, we fix them up a little.  We
- * don't care if they're invalid: the worst that can happen is a General
- * Protection Fault in the Switcher when it restores a Guest segment register
- * which tries to use that entry.  Then we kill the Guest for causing such a
- * mess: the message will be "unhandled trap 256".
- */
-static void fixup_gdt_table(struct lg_cpu *cpu, unsigned start, unsigned end)
-{
-	unsigned int i;
-
-	for (i = start; i < end; i++) {
-		/*
-		 * We never copy these ones to real GDT, so we don't care what
-		 * they say
-		 */
-		if (ignored_gdt(i))
-			continue;
-
-		/*
-		 * Segment descriptors contain a privilege level: the Guest is
-		 * sometimes careless and leaves this as 0, even though it's
-		 * running at privilege level 1.  If so, we fix it here.
-		 */
-		if (cpu->arch.gdt[i].dpl == 0)
-			cpu->arch.gdt[i].dpl |= GUEST_PL;
-
-		/*
-		 * Each descriptor has an "accessed" bit.  If we don't set it
-		 * now, the CPU will try to set it when the Guest first loads
-		 * that entry into a segment register.  But the GDT isn't
-		 * writable by the Guest, so bad things can happen.
-		 */
-		cpu->arch.gdt[i].type |= 0x1;
-	}
-}
-
-/*H:610
- * Like the IDT, we never simply use the GDT the Guest gives us.  We keep
- * a GDT for each CPU, and copy across the Guest's entries each time we want to
- * run the Guest on that CPU.
- *
- * This routine is called at boot or modprobe time for each CPU to set up the
- * constant GDT entries: the ones which are the same no matter what Guest we're
- * running.
- */
-void setup_default_gdt_entries(struct lguest_ro_state *state)
-{
-	struct desc_struct *gdt = state->guest_gdt;
-	unsigned long tss = (unsigned long)&state->guest_tss;
-
-	/* The Switcher segments are full 0-4G segments, privilege level 0 */
-	gdt[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
-	gdt[GDT_ENTRY_LGUEST_DS] = FULL_SEGMENT;
-
-	/*
-	 * The TSS segment refers to the TSS entry for this particular CPU.
-	 */
-	gdt[GDT_ENTRY_TSS].a = 0;
-	gdt[GDT_ENTRY_TSS].b = 0;
-
-	gdt[GDT_ENTRY_TSS].limit0 = 0x67;
-	gdt[GDT_ENTRY_TSS].base0  = tss & 0xFFFF;
-	gdt[GDT_ENTRY_TSS].base1  = (tss >> 16) & 0xFF;
-	gdt[GDT_ENTRY_TSS].base2  = tss >> 24;
-	gdt[GDT_ENTRY_TSS].type   = 0x9; /* 32-bit TSS (available) */
-	gdt[GDT_ENTRY_TSS].p      = 0x1; /* Entry is present */
-	gdt[GDT_ENTRY_TSS].dpl    = 0x0; /* Privilege level 0 */
-	gdt[GDT_ENTRY_TSS].s      = 0x0; /* system segment */
-
-}
-
-/*
- * This routine sets up the initial Guest GDT for booting.  All entries start
- * as 0 (unusable).
- */
-void setup_guest_gdt(struct lg_cpu *cpu)
-{
-	/*
-	 * Start with full 0-4G segments...except the Guest is allowed to use
-	 * them, so set the privilege level appropriately in the flags.
-	 */
-	cpu->arch.gdt[GDT_ENTRY_KERNEL_CS] = FULL_EXEC_SEGMENT;
-	cpu->arch.gdt[GDT_ENTRY_KERNEL_DS] = FULL_SEGMENT;
-	cpu->arch.gdt[GDT_ENTRY_KERNEL_CS].dpl |= GUEST_PL;
-	cpu->arch.gdt[GDT_ENTRY_KERNEL_DS].dpl |= GUEST_PL;
-}
-
-/*H:650
- * An optimization of copy_gdt(), for just the three "thead-local storage"
- * entries.
- */
-void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt)
-{
-	unsigned int i;
-
-	for (i = GDT_ENTRY_TLS_MIN; i <= GDT_ENTRY_TLS_MAX; i++)
-		gdt[i] = cpu->arch.gdt[i];
-}
-
-/*H:640
- * When the Guest is run on a different CPU, or the GDT entries have changed,
- * copy_gdt() is called to copy the Guest's GDT entries across to this CPU's
- * GDT.
- */
-void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt)
-{
-	unsigned int i;
-
-	/*
-	 * The default entries from setup_default_gdt_entries() are not
-	 * replaced.  See ignored_gdt() above.
-	 */
-	for (i = 0; i < GDT_ENTRIES; i++)
-		if (!ignored_gdt(i))
-			gdt[i] = cpu->arch.gdt[i];
-}
-
-/*H:620
- * This is where the Guest asks us to load a new GDT entry
- * (LHCALL_LOAD_GDT_ENTRY).  We tweak the entry and copy it in.
- */
-void load_guest_gdt_entry(struct lg_cpu *cpu, u32 num, u32 lo, u32 hi)
-{
-	/*
-	 * We assume the Guest has the same number of GDT entries as the
-	 * Host, otherwise we'd have to dynamically allocate the Guest GDT.
-	 */
-	if (num >= ARRAY_SIZE(cpu->arch.gdt)) {
-		kill_guest(cpu, "too many gdt entries %i", num);
-		return;
-	}
-
-	/* Set it up, then fix it. */
-	cpu->arch.gdt[num].a = lo;
-	cpu->arch.gdt[num].b = hi;
-	fixup_gdt_table(cpu, num, num+1);
-	/*
-	 * Mark that the GDT changed so the core knows it has to copy it again,
-	 * even if the Guest is run on the same CPU.
-	 */
-	cpu->changed |= CHANGED_GDT;
-}
-
-/*
- * This is the fast-track version for just changing the three TLS entries.
- * Remember that this happens on every context switch, so it's worth
- * optimizing.  But wouldn't it be neater to have a single hypercall to cover
- * both cases?
- */
-void guest_load_tls(struct lg_cpu *cpu, unsigned long gtls)
-{
-	struct desc_struct *tls = &cpu->arch.gdt[GDT_ENTRY_TLS_MIN];
-
-	__lgread(cpu, tls, gtls, sizeof(*tls)*GDT_ENTRY_TLS_ENTRIES);
-	fixup_gdt_table(cpu, GDT_ENTRY_TLS_MIN, GDT_ENTRY_TLS_MAX+1);
-	/* Note that just the TLS entries have changed. */
-	cpu->changed |= CHANGED_GDT_TLS;
-}
-
-/*H:660
- * With this, we have finished the Host.
- *
- * Five of the seven parts of our task are complete.  You have made it through
- * the Bit of Despair (I think that's somewhere in the page table code,
- * myself).
- *
- * Next, we examine "make Switcher".  It's short, but intense.
- */
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
deleted file mode 100644
index b4f79b923aea..000000000000
--- a/drivers/lguest/x86/core.c
+++ /dev/null
@@ -1,724 +0,0 @@
-/*
- * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation.
- * Copyright (C) 2007, Jes Sorensen <jes@sgi.com> SGI.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-/*P:450
- * This file contains the x86-specific lguest code.  It used to be all
- * mixed in with drivers/lguest/core.c but several foolhardy code slashers
- * wrestled most of the dependencies out to here in preparation for porting
- * lguest to other architectures (see what I mean by foolhardy?).
- *
- * This also contains a couple of non-obvious setup and teardown pieces which
- * were implemented after days of debugging pain.
-:*/
-#include <linux/kernel.h>
-#include <linux/start_kernel.h>
-#include <linux/string.h>
-#include <linux/console.h>
-#include <linux/screen_info.h>
-#include <linux/irq.h>
-#include <linux/interrupt.h>
-#include <linux/clocksource.h>
-#include <linux/clockchips.h>
-#include <linux/cpu.h>
-#include <linux/lguest.h>
-#include <linux/lguest_launcher.h>
-#include <asm/paravirt.h>
-#include <asm/param.h>
-#include <asm/page.h>
-#include <asm/pgtable.h>
-#include <asm/desc.h>
-#include <asm/setup.h>
-#include <asm/lguest.h>
-#include <linux/uaccess.h>
-#include <asm/fpu/internal.h>
-#include <asm/tlbflush.h>
-#include "../lg.h"
-
-static int cpu_had_pge;
-
-static struct {
-	unsigned long offset;
-	unsigned short segment;
-} lguest_entry;
-
-/* Offset from where switcher.S was compiled to where we've copied it */
-static unsigned long switcher_offset(void)
-{
-	return switcher_addr - (unsigned long)start_switcher_text;
-}
-
-/* This cpu's struct lguest_pages (after the Switcher text page) */
-static struct lguest_pages *lguest_pages(unsigned int cpu)
-{
-	return &(((struct lguest_pages *)(switcher_addr + PAGE_SIZE))[cpu]);
-}
-
-static DEFINE_PER_CPU(struct lg_cpu *, lg_last_cpu);
-
-/*S:010
- * We approach the Switcher.
- *
- * Remember that each CPU has two pages which are visible to the Guest when it
- * runs on that CPU.  This has to contain the state for that Guest: we copy the
- * state in just before we run the Guest.
- *
- * Each Guest has "changed" flags which indicate what has changed in the Guest
- * since it last ran.  We saw this set in interrupts_and_traps.c and
- * segments.c.
- */
-static void copy_in_guest_info(struct lg_cpu *cpu, struct lguest_pages *pages)
-{
-	/*
-	 * Copying all this data can be quite expensive.  We usually run the
-	 * same Guest we ran last time (and that Guest hasn't run anywhere else
-	 * meanwhile).  If that's not the case, we pretend everything in the
-	 * Guest has changed.
-	 */
-	if (__this_cpu_read(lg_last_cpu) != cpu || cpu->last_pages != pages) {
-		__this_cpu_write(lg_last_cpu, cpu);
-		cpu->last_pages = pages;
-		cpu->changed = CHANGED_ALL;
-	}
-
-	/*
-	 * These copies are pretty cheap, so we do them unconditionally: */
-	/* Save the current Host top-level page directory.
-	 */
-	pages->state.host_cr3 = __pa(current->mm->pgd);
-	/*
-	 * Set up the Guest's page tables to see this CPU's pages (and no
-	 * other CPU's pages).
-	 */
-	map_switcher_in_guest(cpu, pages);
-	/*
-	 * Set up the two "TSS" members which tell the CPU what stack to use
-	 * for traps which do directly into the Guest (ie. traps at privilege
-	 * level 1).
-	 */
-	pages->state.guest_tss.sp1 = cpu->esp1;
-	pages->state.guest_tss.ss1 = cpu->ss1;
-
-	/* Copy direct-to-Guest trap entries. */
-	if (cpu->changed & CHANGED_IDT)
-		copy_traps(cpu, pages->state.guest_idt, default_idt_entries);
-
-	/* Copy all GDT entries which the Guest can change. */
-	if (cpu->changed & CHANGED_GDT)
-		copy_gdt(cpu, pages->state.guest_gdt);
-	/* If only the TLS entries have changed, copy them. */
-	else if (cpu->changed & CHANGED_GDT_TLS)
-		copy_gdt_tls(cpu, pages->state.guest_gdt);
-
-	/* Mark the Guest as unchanged for next time. */
-	cpu->changed = 0;
-}
-
-/* Finally: the code to actually call into the Switcher to run the Guest. */
-static void run_guest_once(struct lg_cpu *cpu, struct lguest_pages *pages)
-{
-	/* This is a dummy value we need for GCC's sake. */
-	unsigned int clobber;
-
-	/*
-	 * Copy the guest-specific information into this CPU's "struct
-	 * lguest_pages".
-	 */
-	copy_in_guest_info(cpu, pages);
-
-	/*
-	 * Set the trap number to 256 (impossible value).  If we fault while
-	 * switching to the Guest (bad segment registers or bug), this will
-	 * cause us to abort the Guest.
-	 */
-	cpu->regs->trapnum = 256;
-
-	/*
-	 * Now: we push the "eflags" register on the stack, then do an "lcall".
-	 * This is how we change from using the kernel code segment to using
-	 * the dedicated lguest code segment, as well as jumping into the
-	 * Switcher.
-	 *
-	 * The lcall also pushes the old code segment (KERNEL_CS) onto the
-	 * stack, then the address of this call.  This stack layout happens to
-	 * exactly match the stack layout created by an interrupt...
-	 */
-	asm volatile("pushf; lcall *%4"
-		     /*
-		      * This is how we tell GCC that %eax ("a") and %ebx ("b")
-		      * are changed by this routine.  The "=" means output.
-		      */
-		     : "=a"(clobber), "=b"(clobber)
-		     /*
-		      * %eax contains the pages pointer.  ("0" refers to the
-		      * 0-th argument above, ie "a").  %ebx contains the
-		      * physical address of the Guest's top-level page
-		      * directory.
-		      */
-		     : "0"(pages), 
-		       "1"(__pa(cpu->lg->pgdirs[cpu->cpu_pgd].pgdir)),
-		       "m"(lguest_entry)
-		     /*
-		      * We tell gcc that all these registers could change,
-		      * which means we don't have to save and restore them in
-		      * the Switcher.
-		      */
-		     : "memory", "%edx", "%ecx", "%edi", "%esi");
-}
-/*:*/
-
-unsigned long *lguest_arch_regptr(struct lg_cpu *cpu, size_t reg_off, bool any)
-{
-	switch (reg_off) {
-	case offsetof(struct pt_regs, bx):
-		return &cpu->regs->ebx;
-	case offsetof(struct pt_regs, cx):
-		return &cpu->regs->ecx;
-	case offsetof(struct pt_regs, dx):
-		return &cpu->regs->edx;
-	case offsetof(struct pt_regs, si):
-		return &cpu->regs->esi;
-	case offsetof(struct pt_regs, di):
-		return &cpu->regs->edi;
-	case offsetof(struct pt_regs, bp):
-		return &cpu->regs->ebp;
-	case offsetof(struct pt_regs, ax):
-		return &cpu->regs->eax;
-	case offsetof(struct pt_regs, ip):
-		return &cpu->regs->eip;
-	case offsetof(struct pt_regs, sp):
-		return &cpu->regs->esp;
-	}
-
-	/* Launcher can read these, but we don't allow any setting. */
-	if (any) {
-		switch (reg_off) {
-		case offsetof(struct pt_regs, ds):
-			return &cpu->regs->ds;
-		case offsetof(struct pt_regs, es):
-			return &cpu->regs->es;
-		case offsetof(struct pt_regs, fs):
-			return &cpu->regs->fs;
-		case offsetof(struct pt_regs, gs):
-			return &cpu->regs->gs;
-		case offsetof(struct pt_regs, cs):
-			return &cpu->regs->cs;
-		case offsetof(struct pt_regs, flags):
-			return &cpu->regs->eflags;
-		case offsetof(struct pt_regs, ss):
-			return &cpu->regs->ss;
-		}
-	}
-
-	return NULL;
-}
-
-/*M:002
- * There are hooks in the scheduler which we can register to tell when we
- * get kicked off the CPU (preempt_notifier_register()).  This would allow us
- * to lazily disable SYSENTER which would regain some performance, and should
- * also simplify copy_in_guest_info().  Note that we'd still need to restore
- * things when we exit to Launcher userspace, but that's fairly easy.
- *
- * We could also try using these hooks for PGE, but that might be too expensive.
- *
- * The hooks were designed for KVM, but we can also put them to good use.
-:*/
-
-/*H:040
- * This is the i386-specific code to setup and run the Guest.  Interrupts
- * are disabled: we own the CPU.
- */
-void lguest_arch_run_guest(struct lg_cpu *cpu)
-{
-	/*
-	 * SYSENTER is an optimized way of doing system calls.  We can't allow
-	 * it because it always jumps to privilege level 0.  A normal Guest
-	 * won't try it because we don't advertise it in CPUID, but a malicious
-	 * Guest (or malicious Guest userspace program) could, so we tell the
-	 * CPU to disable it before running the Guest.
-	 */
-	if (boot_cpu_has(X86_FEATURE_SEP))
-		wrmsr(MSR_IA32_SYSENTER_CS, 0, 0);
-
-	/*
-	 * Now we actually run the Guest.  It will return when something
-	 * interesting happens, and we can examine its registers to see what it
-	 * was doing.
-	 */
-	run_guest_once(cpu, lguest_pages(raw_smp_processor_id()));
-
-	/*
-	 * Note that the "regs" structure contains two extra entries which are
-	 * not really registers: a trap number which says what interrupt or
-	 * trap made the switcher code come back, and an error code which some
-	 * traps set.
-	 */
-
-	 /* Restore SYSENTER if it's supposed to be on. */
-	 if (boot_cpu_has(X86_FEATURE_SEP))
-		wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
-
-	/*
-	 * If the Guest page faulted, then the cr2 register will tell us the
-	 * bad virtual address.  We have to grab this now, because once we
-	 * re-enable interrupts an interrupt could fault and thus overwrite
-	 * cr2, or we could even move off to a different CPU.
-	 */
-	if (cpu->regs->trapnum == 14)
-		cpu->arch.last_pagefault = read_cr2();
-	/*
-	 * Similarly, if we took a trap because the Guest used the FPU,
-	 * we have to restore the FPU it expects to see.
-	 * fpu__restore() may sleep and we may even move off to
-	 * a different CPU. So all the critical stuff should be done
-	 * before this.
-	 */
-	else if (cpu->regs->trapnum == 7 && !fpregs_active())
-		fpu__restore(&current->thread.fpu);
-}
-
-/*H:130
- * Now we've examined the hypercall code; our Guest can make requests.
- * Our Guest is usually so well behaved; it never tries to do things it isn't
- * allowed to, and uses hypercalls instead.  Unfortunately, Linux's paravirtual
- * infrastructure isn't quite complete, because it doesn't contain replacements
- * for the Intel I/O instructions.  As a result, the Guest sometimes fumbles
- * across one during the boot process as it probes for various things which are
- * usually attached to a PC.
- *
- * When the Guest uses one of these instructions, we get a trap (General
- * Protection Fault) and come here.  We queue this to be sent out to the
- * Launcher to handle.
- */
-
-/*
- * The eip contains the *virtual* address of the Guest's instruction:
- * we copy the instruction here so the Launcher doesn't have to walk
- * the page tables to decode it.  We handle the case (eg. in a kernel
- * module) where the instruction is over two pages, and the pages are
- * virtually but not physically contiguous.
- *
- * The longest possible x86 instruction is 15 bytes, but we don't handle
- * anything that strange.
- */
-static void copy_from_guest(struct lg_cpu *cpu,
-			    void *dst, unsigned long vaddr, size_t len)
-{
-	size_t to_page_end = PAGE_SIZE - (vaddr % PAGE_SIZE);
-	unsigned long paddr;
-
-	BUG_ON(len > PAGE_SIZE);
-
-	/* If it goes over a page, copy in two parts. */
-	if (len > to_page_end) {
-		/* But make sure the next page is mapped! */
-		if (__guest_pa(cpu, vaddr + to_page_end, &paddr))
-			copy_from_guest(cpu, dst + to_page_end,
-					vaddr + to_page_end,
-					len - to_page_end);
-		else
-			/* Otherwise fill with zeroes. */
-			memset(dst + to_page_end, 0, len - to_page_end);
-		len = to_page_end;
-	}
-
-	/* This will kill the guest if it isn't mapped, but that
-	 * shouldn't happen. */
-	__lgread(cpu, dst, guest_pa(cpu, vaddr), len);
-}
-
-
-static void setup_emulate_insn(struct lg_cpu *cpu)
-{
-	cpu->pending.trap = 13;
-	copy_from_guest(cpu, cpu->pending.insn, cpu->regs->eip,
-			sizeof(cpu->pending.insn));
-}
-
-static void setup_iomem_insn(struct lg_cpu *cpu, unsigned long iomem_addr)
-{
-	cpu->pending.trap = 14;
-	cpu->pending.addr = iomem_addr;
-	copy_from_guest(cpu, cpu->pending.insn, cpu->regs->eip,
-			sizeof(cpu->pending.insn));
-}
-
-/*H:050 Once we've re-enabled interrupts, we look at why the Guest exited. */
-void lguest_arch_handle_trap(struct lg_cpu *cpu)
-{
-	unsigned long iomem_addr;
-
-	switch (cpu->regs->trapnum) {
-	case 13: /* We've intercepted a General Protection Fault. */
-		/* Hand to Launcher to emulate those pesky IN and OUT insns */
-		if (cpu->regs->errcode == 0) {
-			setup_emulate_insn(cpu);
-			return;
-		}
-		break;
-	case 14: /* We've intercepted a Page Fault. */
-		/*
-		 * The Guest accessed a virtual address that wasn't mapped.
-		 * This happens a lot: we don't actually set up most of the page
-		 * tables for the Guest at all when we start: as it runs it asks
-		 * for more and more, and we set them up as required. In this
-		 * case, we don't even tell the Guest that the fault happened.
-		 *
-		 * The errcode tells whether this was a read or a write, and
-		 * whether kernel or userspace code.
-		 */
-		if (demand_page(cpu, cpu->arch.last_pagefault,
-				cpu->regs->errcode, &iomem_addr))
-			return;
-
-		/* Was this an access to memory mapped IO? */
-		if (iomem_addr) {
-			/* Tell Launcher, let it handle it. */
-			setup_iomem_insn(cpu, iomem_addr);
-			return;
-		}
-
-		/*
-		 * OK, it's really not there (or not OK): the Guest needs to
-		 * know.  We write out the cr2 value so it knows where the
-		 * fault occurred.
-		 *
-		 * Note that if the Guest were really messed up, this could
-		 * happen before it's done the LHCALL_LGUEST_INIT hypercall, so
-		 * lg->lguest_data could be NULL
-		 */
-		if (cpu->lg->lguest_data &&
-		    put_user(cpu->arch.last_pagefault,
-			     &cpu->lg->lguest_data->cr2))
-			kill_guest(cpu, "Writing cr2");
-		break;
-	case 7: /* We've intercepted a Device Not Available fault. */
-		/* No special handling is needed here. */
-		break;
-	case 32 ... 255:
-		/* This might be a syscall. */
-		if (could_be_syscall(cpu->regs->trapnum))
-			break;
-
-		/*
-		 * Other values mean a real interrupt occurred, in which case
-		 * the Host handler has already been run. We just do a
-		 * friendly check if another process should now be run, then
-		 * return to run the Guest again.
-		 */
-		cond_resched();
-		return;
-	case LGUEST_TRAP_ENTRY:
-		/*
-		 * Our 'struct hcall_args' maps directly over our regs: we set
-		 * up the pointer now to indicate a hypercall is pending.
-		 */
-		cpu->hcall = (struct hcall_args *)cpu->regs;
-		return;
-	}
-
-	/* We didn't handle the trap, so it needs to go to the Guest. */
-	if (!deliver_trap(cpu, cpu->regs->trapnum))
-		/*
-		 * If the Guest doesn't have a handler (either it hasn't
-		 * registered any yet, or it's one of the faults we don't let
-		 * it handle), it dies with this cryptic error message.
-		 */
-		kill_guest(cpu, "unhandled trap %li at %#lx (%#lx)",
-			   cpu->regs->trapnum, cpu->regs->eip,
-			   cpu->regs->trapnum == 14 ? cpu->arch.last_pagefault
-			   : cpu->regs->errcode);
-}
-
-/*
- * Now we can look at each of the routines this calls, in increasing order of
- * complexity: do_hypercalls(), emulate_insn(), maybe_do_interrupt(),
- * deliver_trap() and demand_page().  After all those, we'll be ready to
- * examine the Switcher, and our philosophical understanding of the Host/Guest
- * duality will be complete.
-:*/
-static void adjust_pge(void *on)
-{
-	if (on)
-		cr4_set_bits(X86_CR4_PGE);
-	else
-		cr4_clear_bits(X86_CR4_PGE);
-}
-
-/*H:020
- * Now the Switcher is mapped and every thing else is ready, we need to do
- * some more i386-specific initialization.
- */
-void __init lguest_arch_host_init(void)
-{
-	int i;
-
-	/*
-	 * Most of the x86/switcher_32.S doesn't care that it's been moved; on
-	 * Intel, jumps are relative, and it doesn't access any references to
-	 * external code or data.
-	 *
-	 * The only exception is the interrupt handlers in switcher.S: their
-	 * addresses are placed in a table (default_idt_entries), so we need to
-	 * update the table with the new addresses.  switcher_offset() is a
-	 * convenience function which returns the distance between the
-	 * compiled-in switcher code and the high-mapped copy we just made.
-	 */
-	for (i = 0; i < IDT_ENTRIES; i++)
-		default_idt_entries[i] += switcher_offset();
-
-	/*
-	 * Set up the Switcher's per-cpu areas.
-	 *
-	 * Each CPU gets two pages of its own within the high-mapped region
-	 * (aka. "struct lguest_pages").  Much of this can be initialized now,
-	 * but some depends on what Guest we are running (which is set up in
-	 * copy_in_guest_info()).
-	 */
-	for_each_possible_cpu(i) {
-		/* lguest_pages() returns this CPU's two pages. */
-		struct lguest_pages *pages = lguest_pages(i);
-		/* This is a convenience pointer to make the code neater. */
-		struct lguest_ro_state *state = &pages->state;
-
-		/*
-		 * The Global Descriptor Table: the Host has a different one
-		 * for each CPU.  We keep a descriptor for the GDT which says
-		 * where it is and how big it is (the size is actually the last
-		 * byte, not the size, hence the "-1").
-		 */
-		state->host_gdt_desc.size = GDT_SIZE-1;
-		state->host_gdt_desc.address = (long)get_cpu_gdt_rw(i);
-
-		/*
-		 * All CPUs on the Host use the same Interrupt Descriptor
-		 * Table, so we just use store_idt(), which gets this CPU's IDT
-		 * descriptor.
-		 */
-		store_idt(&state->host_idt_desc);
-
-		/*
-		 * The descriptors for the Guest's GDT and IDT can be filled
-		 * out now, too.  We copy the GDT & IDT into ->guest_gdt and
-		 * ->guest_idt before actually running the Guest.
-		 */
-		state->guest_idt_desc.size = sizeof(state->guest_idt)-1;
-		state->guest_idt_desc.address = (long)&state->guest_idt;
-		state->guest_gdt_desc.size = sizeof(state->guest_gdt)-1;
-		state->guest_gdt_desc.address = (long)&state->guest_gdt;
-
-		/*
-		 * We know where we want the stack to be when the Guest enters
-		 * the Switcher: in pages->regs.  The stack grows upwards, so
-		 * we start it at the end of that structure.
-		 */
-		state->guest_tss.sp0 = (long)(&pages->regs + 1);
-		/*
-		 * And this is the GDT entry to use for the stack: we keep a
-		 * couple of special LGUEST entries.
-		 */
-		state->guest_tss.ss0 = LGUEST_DS;
-
-		/*
-		 * x86 can have a finegrained bitmap which indicates what I/O
-		 * ports the process can use.  We set it to the end of our
-		 * structure, meaning "none".
-		 */
-		state->guest_tss.io_bitmap_base = sizeof(state->guest_tss);
-
-		/*
-		 * Some GDT entries are the same across all Guests, so we can
-		 * set them up now.
-		 */
-		setup_default_gdt_entries(state);
-		/* Most IDT entries are the same for all Guests, too.*/
-		setup_default_idt_entries(state, default_idt_entries);
-
-		/*
-		 * The Host needs to be able to use the LGUEST segments on this
-		 * CPU, too, so put them in the Host GDT.
-		 */
-		get_cpu_gdt_rw(i)[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
-		get_cpu_gdt_rw(i)[GDT_ENTRY_LGUEST_DS] = FULL_SEGMENT;
-	}
-
-	/*
-	 * In the Switcher, we want the %cs segment register to use the
-	 * LGUEST_CS GDT entry: we've put that in the Host and Guest GDTs, so
-	 * it will be undisturbed when we switch.  To change %cs and jump we
-	 * need this structure to feed to Intel's "lcall" instruction.
-	 */
-	lguest_entry.offset = (long)switch_to_guest + switcher_offset();
-	lguest_entry.segment = LGUEST_CS;
-
-	/*
-	 * Finally, we need to turn off "Page Global Enable".  PGE is an
-	 * optimization where page table entries are specially marked to show
-	 * they never change.  The Host kernel marks all the kernel pages this
-	 * way because it's always present, even when userspace is running.
-	 *
-	 * Lguest breaks this: unbeknownst to the rest of the Host kernel, we
-	 * switch to the Guest kernel.  If you don't disable this on all CPUs,
-	 * you'll get really weird bugs that you'll chase for two days.
-	 *
-	 * I used to turn PGE off every time we switched to the Guest and back
-	 * on when we return, but that slowed the Switcher down noticibly.
-	 */
-
-	/*
-	 * We don't need the complexity of CPUs coming and going while we're
-	 * doing this.
-	 */
-	get_online_cpus();
-	if (boot_cpu_has(X86_FEATURE_PGE)) { /* We have a broader idea of "global". */
-		/* Remember that this was originally set (for cleanup). */
-		cpu_had_pge = 1;
-		/*
-		 * adjust_pge is a helper function which sets or unsets the PGE
-		 * bit on its CPU, depending on the argument (0 == unset).
-		 */
-		on_each_cpu(adjust_pge, (void *)0, 1);
-		/* Turn off the feature in the global feature set. */
-		clear_cpu_cap(&boot_cpu_data, X86_FEATURE_PGE);
-	}
-	put_online_cpus();
-}
-/*:*/
-
-void __exit lguest_arch_host_fini(void)
-{
-	/* If we had PGE before we started, turn it back on now. */
-	get_online_cpus();
-	if (cpu_had_pge) {
-		set_cpu_cap(&boot_cpu_data, X86_FEATURE_PGE);
-		/* adjust_pge's argument "1" means set PGE. */
-		on_each_cpu(adjust_pge, (void *)1, 1);
-	}
-	put_online_cpus();
-}
-
-
-/*H:122 The i386-specific hypercalls simply farm out to the right functions. */
-int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
-{
-	switch (args->arg0) {
-	case LHCALL_LOAD_GDT_ENTRY:
-		load_guest_gdt_entry(cpu, args->arg1, args->arg2, args->arg3);
-		break;
-	case LHCALL_LOAD_IDT_ENTRY:
-		load_guest_idt_entry(cpu, args->arg1, args->arg2, args->arg3);
-		break;
-	case LHCALL_LOAD_TLS:
-		guest_load_tls(cpu, args->arg1);
-		break;
-	default:
-		/* Bad Guest.  Bad! */
-		return -EIO;
-	}
-	return 0;
-}
-
-/*H:126 i386-specific hypercall initialization: */
-int lguest_arch_init_hypercalls(struct lg_cpu *cpu)
-{
-	u32 tsc_speed;
-
-	/*
-	 * The pointer to the Guest's "struct lguest_data" is the only argument.
-	 * We check that address now.
-	 */
-	if (!lguest_address_ok(cpu->lg, cpu->hcall->arg1,
-			       sizeof(*cpu->lg->lguest_data)))
-		return -EFAULT;
-
-	/*
-	 * Having checked it, we simply set lg->lguest_data to point straight
-	 * into the Launcher's memory at the right place and then use
-	 * copy_to_user/from_user from now on, instead of lgread/write.  I put
-	 * this in to show that I'm not immune to writing stupid
-	 * optimizations.
-	 */
-	cpu->lg->lguest_data = cpu->lg->mem_base + cpu->hcall->arg1;
-
-	/*
-	 * We insist that the Time Stamp Counter exist and doesn't change with
-	 * cpu frequency.  Some devious chip manufacturers decided that TSC
-	 * changes could be handled in software.  I decided that time going
-	 * backwards might be good for benchmarks, but it's bad for users.
-	 *
-	 * We also insist that the TSC be stable: the kernel detects unreliable
-	 * TSCs for its own purposes, and we use that here.
-	 */
-	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
-		tsc_speed = tsc_khz;
-	else
-		tsc_speed = 0;
-	if (put_user(tsc_speed, &cpu->lg->lguest_data->tsc_khz))
-		return -EFAULT;
-
-	/* The interrupt code might not like the system call vector. */
-	if (!check_syscall_vector(cpu->lg))
-		kill_guest(cpu, "bad syscall vector");
-
-	return 0;
-}
-/*:*/
-
-/*L:030
- * Most of the Guest's registers are left alone: we used get_zeroed_page() to
- * allocate the structure, so they will be 0.
- */
-void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start)
-{
-	struct lguest_regs *regs = cpu->regs;
-
-	/*
-	 * There are four "segment" registers which the Guest needs to boot:
-	 * The "code segment" register (cs) refers to the kernel code segment
-	 * __KERNEL_CS, and the "data", "extra" and "stack" segment registers
-	 * refer to the kernel data segment __KERNEL_DS.
-	 *
-	 * The privilege level is packed into the lower bits.  The Guest runs
-	 * at privilege level 1 (GUEST_PL).
-	 */
-	regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
-	regs->cs = __KERNEL_CS|GUEST_PL;
-
-	/*
-	 * The "eflags" register contains miscellaneous flags.  Bit 1 (0x002)
-	 * is supposed to always be "1".  Bit 9 (0x200) controls whether
-	 * interrupts are enabled.  We always leave interrupts enabled while
-	 * running the Guest.
-	 */
-	regs->eflags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
-
-	/*
-	 * The "Extended Instruction Pointer" register says where the Guest is
-	 * running.
-	 */
-	regs->eip = start;
-
-	/*
-	 * %esi points to our boot information, at physical address 0, so don't
-	 * touch it.
-	 */
-
-	/* There are a couple of GDT entries the Guest expects at boot. */
-	setup_guest_gdt(cpu);
-}
diff --git a/drivers/lguest/x86/switcher_32.S b/drivers/lguest/x86/switcher_32.S
deleted file mode 100644
index 40634b0db9f7..000000000000
--- a/drivers/lguest/x86/switcher_32.S
+++ /dev/null
@@ -1,388 +0,0 @@
-/*P:900
- * This is the Switcher: code which sits at 0xFFC00000 (or 0xFFE00000) astride
- * both the Host and Guest to do the low-level Guest<->Host switch.  It is as
- * simple as it can be made, but it's naturally very specific to x86.
- *
- * You have now completed Preparation.  If this has whet your appetite; if you
- * are feeling invigorated and refreshed then the next, more challenging stage
- * can be found in "make Guest".
- :*/
-
-/*M:012
- * Lguest is meant to be simple: my rule of thumb is that 1% more LOC must
- * gain at least 1% more performance.  Since neither LOC nor performance can be
- * measured beforehand, it generally means implementing a feature then deciding
- * if it's worth it.  And once it's implemented, who can say no?
- *
- * This is why I haven't implemented this idea myself.  I want to, but I
- * haven't.  You could, though.
- *
- * The main place where lguest performance sucks is Guest page faulting.  When
- * a Guest userspace process hits an unmapped page we switch back to the Host,
- * walk the page tables, find it's not mapped, switch back to the Guest page
- * fault handler, which calls a hypercall to set the page table entry, then
- * finally returns to userspace.  That's two round-trips.
- *
- * If we had a small walker in the Switcher, we could quickly check the Guest
- * page table and if the page isn't mapped, immediately reflect the fault back
- * into the Guest.  This means the Switcher would have to know the top of the
- * Guest page table and the page fault handler address.
- *
- * For simplicity, the Guest should only handle the case where the privilege
- * level of the fault is 3 and probably only not present or write faults.  It
- * should also detect recursive faults, and hand the original fault to the
- * Host (which is actually really easy).
- *
- * Two questions remain.  Would the performance gain outweigh the complexity?
- * And who would write the verse documenting it?
-:*/
-
-/*M:011
- * Lguest64 handles NMI.  This gave me NMI envy (until I looked at their
- * code).  It's worth doing though, since it would let us use oprofile in the
- * Host when a Guest is running.
-:*/
-
-/*S:100
- * Welcome to the Switcher itself!
- *
- * This file contains the low-level code which changes the CPU to run the Guest
- * code, and returns to the Host when something happens.  Understand this, and
- * you understand the heart of our journey.
- *
- * Because this is in assembler rather than C, our tale switches from prose to
- * verse.  First I tried limericks:
- *
- *	There once was an eax reg,
- *	To which our pointer was fed,
- *	It needed an add,
- *	Which asm-offsets.h had
- *	But this limerick is hurting my head.
- *
- * Next I tried haikus, but fitting the required reference to the seasons in
- * every stanza was quickly becoming tiresome:
- *
- *	The %eax reg
- *	Holds "struct lguest_pages" now:
- *	Cherry blossoms fall.
- *
- * Then I started with Heroic Verse, but the rhyming requirement leeched away
- * the content density and led to some uniquely awful oblique rhymes:
- *
- *	These constants are coming from struct offsets
- *	For use within the asm switcher text.
- *
- * Finally, I settled for something between heroic hexameter, and normal prose
- * with inappropriate linebreaks.  Anyway, it aint no Shakespeare.
- */
-
-// Not all kernel headers work from assembler
-// But these ones are needed: the ENTRY() define
-// And constants extracted from struct offsets
-// To avoid magic numbers and breakage:
-// Should they change the compiler can't save us
-// Down here in the depths of assembler code.
-#include <linux/linkage.h>
-#include <asm/asm-offsets.h>
-#include <asm/page.h>
-#include <asm/segment.h>
-#include <asm/lguest.h>
-
-// We mark the start of the code to copy
-// It's placed in .text tho it's never run here
-// You'll see the trick macro at the end
-// Which interleaves data and text to effect.
-.text
-ENTRY(start_switcher_text)
-
-// When we reach switch_to_guest we have just left
-// The safe and comforting shores of C code
-// %eax has the "struct lguest_pages" to use
-// Where we save state and still see it from the Guest
-// And %ebx holds the Guest shadow pagetable:
-// Once set we have truly left Host behind.
-ENTRY(switch_to_guest)
-	// We told gcc all its regs could fade,
-	// Clobbered by our journey into the Guest
-	// We could have saved them, if we tried
-	// But time is our master and cycles count.
-
-	// Segment registers must be saved for the Host
-	// We push them on the Host stack for later
-	pushl	%es
-	pushl	%ds
-	pushl	%gs
-	pushl	%fs
-	// But the compiler is fickle, and heeds
-	// No warning of %ebp clobbers
-	// When frame pointers are used.  That register
-	// Must be saved and restored or chaos strikes.
-	pushl	%ebp
-	// The Host's stack is done, now save it away
-	// In our "struct lguest_pages" at offset
-	// Distilled into asm-offsets.h
-	movl	%esp, LGUEST_PAGES_host_sp(%eax)
-
-	// All saved and there's now five steps before us:
-	// Stack, GDT, IDT, TSS
-	// Then last of all the page tables are flipped.
-
-	// Yet beware that our stack pointer must be
-	// Always valid lest an NMI hits
-	// %edx does the duty here as we juggle
-	// %eax is lguest_pages: our stack lies within.
-	movl	%eax, %edx
-	addl	$LGUEST_PAGES_regs, %edx
-	movl	%edx, %esp
-
-	// The Guest's GDT we so carefully
-	// Placed in the "struct lguest_pages" before
-	lgdt	LGUEST_PAGES_guest_gdt_desc(%eax)
-
-	// The Guest's IDT we did partially
-	// Copy to "struct lguest_pages" as well.
-	lidt	LGUEST_PAGES_guest_idt_desc(%eax)
-
-	// The TSS entry which controls traps
-	// Must be loaded up with "ltr" now:
-	// The GDT entry that TSS uses 
-	// Changes type when we load it: damn Intel!
-	// For after we switch over our page tables
-	// That entry will be read-only: we'd crash.
-	movl	$(GDT_ENTRY_TSS*8), %edx
-	ltr	%dx
-
-	// Look back now, before we take this last step!
-	// The Host's TSS entry was also marked used;
-	// Let's clear it again for our return.
-	// The GDT descriptor of the Host
-	// Points to the table after two "size" bytes
-	movl	(LGUEST_PAGES_host_gdt_desc+2)(%eax), %edx
-	// Clear "used" from type field (byte 5, bit 2)
-	andb	$0xFD, (GDT_ENTRY_TSS*8 + 5)(%edx)
-
-	// Once our page table's switched, the Guest is live!
-	// The Host fades as we run this final step.
-	// Our "struct lguest_pages" is now read-only.
-	movl	%ebx, %cr3
-
-	// The page table change did one tricky thing:
-	// The Guest's register page has been mapped
-	// Writable under our %esp (stack) --
-	// We can simply pop off all Guest regs.
-	popl	%eax
-	popl	%ebx
-	popl	%ecx
-	popl	%edx
-	popl	%esi
-	popl	%edi
-	popl	%ebp
-	popl	%gs
-	popl	%fs
-	popl	%ds
-	popl	%es
-
-	// Near the base of the stack lurk two strange fields
-	// Which we fill as we exit the Guest
-	// These are the trap number and its error
-	// We can simply step past them on our way.
-	addl	$8, %esp
-
-	// The last five stack slots hold return address
-	// And everything needed to switch privilege
-	// From Switcher's level 0 to Guest's 1,
-	// And the stack where the Guest had last left it.
-	// Interrupts are turned back on: we are Guest.
-	iret
-
-// We tread two paths to switch back to the Host
-// Yet both must save Guest state and restore Host
-// So we put the routine in a macro.
-#define SWITCH_TO_HOST							\
-	/* We save the Guest state: all registers first			\
-	 * Laid out just as "struct lguest_regs" defines */		\
-	pushl	%es;							\
-	pushl	%ds;							\
-	pushl	%fs;							\
-	pushl	%gs;							\
-	pushl	%ebp;							\
-	pushl	%edi;							\
-	pushl	%esi;							\
-	pushl	%edx;							\
-	pushl	%ecx;							\
-	pushl	%ebx;							\
-	pushl	%eax;							\
-	/* Our stack and our code are using segments			\
-	 * Set in the TSS and IDT					\
-	 * Yet if we were to touch data we'd use			\
-	 * Whatever data segment the Guest had.				\
-	 * Load the lguest ds segment for now. */			\
-	movl	$(LGUEST_DS), %eax;					\
-	movl	%eax, %ds;						\
-	/* So where are we?  Which CPU, which struct?			\
-	 * The stack is our clue: our TSS starts			\
-	 * It at the end of "struct lguest_pages".			\
-	 * Or we may have stumbled while restoring			\
-	 * Our Guest segment regs while in switch_to_guest,		\
-	 * The fault pushed atop that part-unwound stack.		\
-	 * If we round the stack down to the page start			\
-	 * We're at the start of "struct lguest_pages". */		\
-	movl	%esp, %eax;						\
-	andl	$(~(1 << PAGE_SHIFT - 1)), %eax;			\
-	/* Save our trap number: the switch will obscure it		\
-	 * (In the Host the Guest regs are not mapped here)		\
-	 * %ebx holds it safe for deliver_to_host */			\
-	movl	LGUEST_PAGES_regs_trapnum(%eax), %ebx;			\
-	/* The Host GDT, IDT and stack!					\
-	 * All these lie safely hidden from the Guest:			\
-	 * We must return to the Host page tables			\
-	 * (Hence that was saved in struct lguest_pages) */		\
-	movl	LGUEST_PAGES_host_cr3(%eax), %edx;			\
-	movl	%edx, %cr3;						\
-	/* As before, when we looked back at the Host			\
-	 * As we left and marked TSS unused				\
-	 * So must we now for the Guest left behind. */			\
-	andb	$0xFD, (LGUEST_PAGES_guest_gdt+GDT_ENTRY_TSS*8+5)(%eax); \
-	/* Switch to Host's GDT, IDT. */				\
-	lgdt	LGUEST_PAGES_host_gdt_desc(%eax);			\
-	lidt	LGUEST_PAGES_host_idt_desc(%eax);			\
-	/* Restore the Host's stack where its saved regs lie */		\
-	movl	LGUEST_PAGES_host_sp(%eax), %esp;			\
-	/* Last the TSS: our Host is returned */			\
-	movl	$(GDT_ENTRY_TSS*8), %edx;				\
-	ltr	%dx;							\
-	/* Restore now the regs saved right at the first. */		\
-	popl	%ebp;							\
-	popl	%fs;							\
-	popl	%gs;							\
-	popl	%ds;							\
-	popl	%es
-
-// The first path is trod when the Guest has trapped:
-// (Which trap it was has been pushed on the stack).
-// We need only switch back, and the Host will decode
-// Why we came home, and what needs to be done.
-return_to_host:
-	SWITCH_TO_HOST
-	iret
-
-// We are lead to the second path like so:
-// An interrupt, with some cause external
-// Has ajerked us rudely from the Guest's code
-// Again we must return home to the Host
-deliver_to_host:
-	SWITCH_TO_HOST
-	// But now we must go home via that place
-	// Where that interrupt was supposed to go
-	// Had we not been ensconced, running the Guest.
-	// Here we see the trickness of run_guest_once():
-	// The Host stack is formed like an interrupt
-	// With EIP, CS and EFLAGS layered.
-	// Interrupt handlers end with "iret"
-	// And that will take us home at long long last.
-
-	// But first we must find the handler to call!
-	// The IDT descriptor for the Host
-	// Has two bytes for size, and four for address:
-	// %edx will hold it for us for now.
-	movl	(LGUEST_PAGES_host_idt_desc+2)(%eax), %edx
-	// We now know the table address we need,
-	// And saved the trap's number inside %ebx.
-	// Yet the pointer to the handler is smeared
-	// Across the bits of the table entry.
-	// What oracle can tell us how to extract
-	// From such a convoluted encoding?
-	// I consulted gcc, and it gave
-	// These instructions, which I gladly credit:
-	leal	(%edx,%ebx,8), %eax
-	movzwl	(%eax),%edx
-	movl	4(%eax), %eax
-	xorw	%ax, %ax
-	orl	%eax, %edx
-	// Now the address of the handler's in %edx
-	// We call it now: its "iret" drops us home.
-	jmp	*%edx
-
-// Every interrupt can come to us here
-// But we must truly tell each apart.
-// They number two hundred and fifty six
-// And each must land in a different spot,
-// Push its number on stack, and join the stream.
-
-// And worse, a mere six of the traps stand apart
-// And push on their stack an addition:
-// An error number, thirty two bits long
-// So we punish the other two fifty
-// And make them push a zero so they match.
-
-// Yet two fifty six entries is long
-// And all will look most the same as the last
-// So we create a macro which can make
-// As many entries as we need to fill.
-
-// Note the change to .data then .text:
-// We plant the address of each entry
-// Into a (data) table for the Host
-// To know where each Guest interrupt should go.
-.macro IRQ_STUB N TARGET
-	.data; .long 1f; .text; 1:
- // Trap eight, ten through fourteen and seventeen
- // Supply an error number.  Else zero.
- .if (\N <> 8) && (\N < 10 || \N > 14) && (\N <> 17)
-	pushl	$0
- .endif
-	pushl	$\N
-	jmp	\TARGET
-	ALIGN
-.endm
-
-// This macro creates numerous entries
-// Using GAS macros which out-power C's.
-.macro IRQ_STUBS FIRST LAST TARGET
- irq=\FIRST
- .rept \LAST-\FIRST+1
-	IRQ_STUB irq \TARGET
-  irq=irq+1
- .endr
-.endm
-
-// Here's the marker for our pointer table
-// Laid in the data section just before
-// Each macro places the address of code
-// Forming an array: each one points to text
-// Which handles interrupt in its turn.
-.data
-.global default_idt_entries
-default_idt_entries:
-.text
-	// The first two traps go straight back to the Host
-	IRQ_STUBS 0 1 return_to_host
-	// We'll say nothing, yet, about NMI
-	IRQ_STUB 2 handle_nmi
-	// Other traps also return to the Host
-	IRQ_STUBS 3 31 return_to_host
-	// All interrupts go via their handlers
-	IRQ_STUBS 32 127 deliver_to_host
-	// 'Cept system calls coming from userspace
-	// Are to go to the Guest, never the Host.
-	IRQ_STUB 128 return_to_host
-	IRQ_STUBS 129 255 deliver_to_host
-
-// The NMI, what a fabulous beast
-// Which swoops in and stops us no matter that
-// We're suspended between heaven and hell,
-// (Or more likely between the Host and Guest)
-// When in it comes!  We are dazed and confused
-// So we do the simplest thing which one can.
-// Though we've pushed the trap number and zero
-// We discard them, return, and hope we live.
-handle_nmi:
-	addl	$8, %esp
-	iret
-
-// We are done; all that's left is Mastery
-// And "make Mastery" is a journey long
-// Designed to make your fingers itch to code.
-
-// Here ends the text, the file and poem.
-ENTRY(end_switcher_text)