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authorAndy Lutomirski <luto@kernel.org>2017-11-02 00:59:09 -0700
committerIngo Molnar <mingo@kernel.org>2017-11-02 11:04:43 +0100
commitbd7dc5a6afac719d8ce4092391eef2c7e83c2a75 (patch)
tree2ee8471b8b2443be14f0badffe69befd7a76f8d2 /arch/x86/kernel/vm86_32.c
parent929bacec21478a72c78e4f29f98fb799bd00105a (diff)
downloadlinux-bd7dc5a6afac719d8ce4092391eef2c7e83c2a75.tar.bz2
x86/entry/32: Pull the MSR_IA32_SYSENTER_CS update code out of native_load_sp0()
This causes the MSR_IA32_SYSENTER_CS write to move out of the paravirt callback. This shouldn't affect Xen PV: Xen already ignores MSR_IA32_SYSENTER_ESP writes. In any event, Xen doesn't support vm86() in a useful way. Note to any potential backporters: This patch won't break lguest, as lguest didn't have any SYSENTER support at all. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bpetkov@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/75cf09fe03ae778532d0ca6c65aa58e66bc2f90c.1509609304.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/vm86_32.c')
-rw-r--r--arch/x86/kernel/vm86_32.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 7924a5356c8a..5bc1c3ab6287 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -54,6 +54,7 @@
#include <asm/irq.h>
#include <asm/traps.h>
#include <asm/vm86.h>
+#include <asm/switch_to.h>
/*
* Known problems:
@@ -149,6 +150,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
tsk->thread.sp0 = vm86->saved_sp0;
tsk->thread.sysenter_cs = __KERNEL_CS;
load_sp0(tss, &tsk->thread);
+ refresh_sysenter_cs(&tsk->thread);
vm86->saved_sp0 = 0;
put_cpu();
@@ -368,8 +370,10 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
/* make room for real-mode segments */
tsk->thread.sp0 += 16;
- if (static_cpu_has(X86_FEATURE_SEP))
+ if (static_cpu_has(X86_FEATURE_SEP)) {
tsk->thread.sysenter_cs = 0;
+ refresh_sysenter_cs(&tsk->thread);
+ }
load_sp0(tss, &tsk->thread);
put_cpu();