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2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 266Thomas Gleixner1-12/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation 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 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 67 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141333.953658117@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-09KVM: PPC: Book3S HV: Framework and hcall stubs for nested virtualizationPaul Mackerras1-0/+3
This starts the process of adding the code to support nested HV-style virtualization. It defines a new H_SET_PARTITION_TABLE hypercall which a nested hypervisor can use to set the base address and size of a partition table in its memory (analogous to the PTCR register). On the host (level 0 hypervisor) side, the H_SET_PARTITION_TABLE hypercall from the guest is handled by code that saves the virtual PTCR value for the guest. This also adds code for creating and destroying nested guests and for reading the partition table entry for a nested guest from L1 memory. Each nested guest has its own shadow LPID value, different in general from the LPID value used by the nested hypervisor to refer to it. The shadow LPID value is allocated at nested guest creation time. Nested hypervisor functionality is only available for a radix guest, which therefore means a radix host on a POWER9 (or later) processor. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-24KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9Paul Mackerras1-0/+1
POWER9 has hardware bugs relating to transactional memory and thread reconfiguration (changes to hardware SMT mode). Specifically, the core does not have enough storage to store a complete checkpoint of all the architected state for all four threads. The DD2.2 version of POWER9 includes hardware modifications designed to allow hypervisor software to implement workarounds for these problems. This patch implements those workarounds in KVM code so that KVM guests see a full, working transactional memory implementation. The problems center around the use of TM suspended state, where the CPU has a checkpointed state but execution is not transactional. The workaround is to implement a "fake suspend" state, which looks to the guest like suspended state but the CPU does not store a checkpoint. In this state, any instruction that would cause a transition to transactional state (rfid, rfebb, mtmsrd, tresume) or would use the checkpointed state (treclaim) causes a "soft patch" interrupt (vector 0x1500) to the hypervisor so that it can be emulated. The trechkpt instruction also causes a soft patch interrupt. On POWER9 DD2.2, we avoid returning to the guest in any state which would require a checkpoint to be present. The trechkpt in the guest entry path which would normally create that checkpoint is replaced by either a transition to fake suspend state, if the guest is in suspend state, or a rollback to the pre-transactional state if the guest is in transactional state. Fake suspend state is indicated by a flag in the PACA plus a new bit in the PSSCR. The new PSSCR bit is write-only and reads back as 0. On exit from the guest, if the guest is in fake suspend state, we still do the treclaim instruction as we would in real suspend state, in order to get into non-transactional state, but we do not save the resulting register state since there was no checkpoint. Emulation of the instructions that cause a softpatch interrupt is handled in two paths. If the guest is in real suspend mode, we call kvmhv_p9_tm_emulation_early() to handle the cases where the guest is transitioning to transactional state. This is called before we do the treclaim in the guest exit path; because we haven't done treclaim, we can get back to the guest with the transaction still active. If the instruction is a case that kvmhv_p9_tm_emulation_early() doesn't handle, or if the guest is in fake suspend state, then we proceed to do the complete guest exit path and subsequently call kvmhv_p9_tm_emulation() in host context with the MMU on. This handles all the cases including the cases that generate program interrupts (illegal instruction or TM Bad Thing) and facility unavailable interrupts. The emulation is reasonably straightforward and is mostly concerned with checking for exception conditions and updating the state of registers such as MSR and CR0. The treclaim emulation takes care to ensure that the TEXASR register gets updated as if it were the guest treclaim instruction that had done failure recording, not the treclaim done in hypervisor state in the guest exit path. With this, the KVM_CAP_PPC_HTM capability returns true (1) even if transactional memory is not available to host userspace. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-01KVM: PPC: Book3S HV: Run HPT guests on POWER9 radix hostsPaul Mackerras1-1/+12
This patch removes the restriction that a radix host can only run radix guests, allowing us to run HPT (hashed page table) guests as well. This is useful because it provides a way to run old guest kernels that know about POWER8 but not POWER9. Unfortunately, POWER9 currently has a restriction that all threads in a given code must either all be in HPT mode, or all in radix mode. This means that when entering a HPT guest, we have to obtain control of all 4 threads in the core and get them to switch their LPIDR and LPCR registers, even if they are not going to run a guest. On guest exit we also have to get all threads to switch LPIDR and LPCR back to host values. To make this feasible, we require that KVM not be in the "independent threads" mode, and that the CPU cores be in single-threaded mode from the host kernel's perspective (only thread 0 online; threads 1, 2 and 3 offline). That allows us to use the same code as on POWER8 for obtaining control of the secondary threads. To manage the LPCR/LPIDR changes required, we extend the kvm_split_info struct to contain the information needed by the secondary threads. All threads perform a barrier synchronization (where all threads wait for every other thread to reach the synchronization point) on guest entry, both before and after loading LPCR and LPIDR. On guest exit, they all once again perform a barrier synchronization both before and after loading host values into LPCR and LPIDR. Finally, it is also currently necessary to flush the entire TLB every time we enter a HPT guest on a radix host. We do this on thread 0 with a loop of tlbiel instructions. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-10-19Revert "KVM: PPC: Book3S HV: POWER9 does not require secondary thread ↵Paul Mackerras1-4/+0
management" This reverts commit 94a04bc25a2c6296bd0c5e82c10e8231c2b11f77. In order to run HPT guests on a radix POWER9 host, we will have to run the host in single-threaded mode, because POWER9 processors do not currently support running some threads of a core in HPT mode while others are in radix mode ("mixed mode"). That means that we will need the same mechanisms that are used on POWER8 to make the secondary threads available to KVM, which were disabled on POWER9 by commit 94a04bc25a2c. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-29KVM: PPC: Book3S HV: POWER9 does not require secondary thread managementNicholas Piggin1-0/+4
POWER9 CPUs have independent MMU contexts per thread, so KVM does not need to quiesce secondary threads, so the hwthread_req/hwthread_state protocol does not have to be used. So patch it away on POWER9, and patch away the branch from the Linux idle wakeup to kvm_start_guest that is never used. Add a warning and error out of kvmppc_grab_hwthread in case it is ever called on POWER9. This avoids a hwsync in the idle wakeup path on POWER9. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Paul Mackerras <paulus@ozlabs.org> [mpe: Use WARN(...) instead of WARN_ON()/pr_err(...)] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-01KVM: PPC: Book3S HV: Simplify dynamic micro-threading codePaul Mackerras1-1/+1
Since commit b009031f74da ("KVM: PPC: Book3S HV: Take out virtual core piggybacking code", 2016-09-15), we only have at most one vcore per subcore. Previously, the fact that there might be more than one vcore per subcore meant that we had the notion of a "master vcore", which was the vcore that controlled thread 0 of the subcore. We also needed a list per subcore in the core_info struct to record which vcores belonged to each subcore. Now that there can only be one vcore in the subcore, we can replace the list with a simple pointer and get rid of the notion of the master vcore (and in fact treat every vcore as a master vcore). We can also get rid of the subcore_vm[] field in the core_info struct since it is never read. Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-04-27KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controllerBenjamin Herrenschmidt1-0/+2
This patch makes KVM capable of using the XIVE interrupt controller to provide the standard PAPR "XICS" style hypercalls. It is necessary for proper operations when the host uses XIVE natively. This has been lightly tested on an actual system, including PCI pass-through with a TG3 device. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [mpe: Cleanup pr_xxx(), unsplit pr_xxx() strings, etc., fix build failures by adding KVM_XIVE which depends on KVM_XICS and XIVE, and adding empty stubs for the kvm_xive_xxx() routines, fixup subject, integrate fixes from Paul for building PR=y HV=n] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-10powerpc: Consolidate variants of real-mode MMIOsBenjamin Herrenschmidt1-1/+1
We have all sort of variants of MMIO accessors for the real mode instructions. This creates a clean set of accessors based on Linux normal naming conventions, replacing all occurrences of the old ones in the tree. I have purposefully removed the "out/in" variants in favor of only including __raw variants. Any code using these is already pretty much hand tuned to operate in a very specific environment. I've fixed up the 2 users (only one of them actually needed a barrier in the first place). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-15powerpc/powernv: Add platform support for stop instructionShreyas B. Prabhu1-1/+1
POWER ISA v3 defines a new idle processor core mechanism. In summary, a) new instruction named stop is added. This instruction replaces instructions like nap, sleep, rvwinkle. b) new per thread SPR named Processor Stop Status and Control Register (PSSCR) is added which controls the behavior of stop instruction. PSSCR layout: ---------------------------------------------------------- | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL | ---------------------------------------------------------- 0 4 41 42 43 44 48 54 56 60 PSSCR key fields: Bits 0:3 - Power-Saving Level Status. This field indicates the lowest power-saving state the thread entered since stop instruction was last executed. Bit 42 - Enable State Loss 0 - No state is lost irrespective of other fields 1 - Allows state loss Bits 44:47 - Power-Saving Level Limit This limits the power-saving level that can be entered into. Bits 60:63 - Requested Level Used to specify which power-saving level must be entered on executing stop instruction This patch adds support for stop instruction and PSSCR handling. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-08-22KVM: PPC: Book3S: correct width in XER handlingSam bobroff1-1/+1
In 64 bit kernels, the Fixed Point Exception Register (XER) is a 64 bit field (e.g. in kvm_regs and kvm_vcpu_arch) and in most places it is accessed as such. This patch corrects places where it is accessed as a 32 bit field by a 64 bit kernel. In some cases this is via a 32 bit load or store instruction which, depending on endianness, will cause either the lower or upper 32 bits to be missed. In another case it is cast as a u32, causing the upper 32 bits to be cleared. This patch corrects those places by extending the access methods to 64 bits. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Reviewed-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Tested-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-08-22KVM: PPC: Book3S HV: Implement dynamic micro-threading on POWER8Paul Mackerras1-0/+20
This builds on the ability to run more than one vcore on a physical core by using the micro-threading (split-core) modes of the POWER8 chip. Previously, only vcores from the same VM could be run together, and (on POWER8) only if they had just one thread per core. With the ability to split the core on guest entry and unsplit it on guest exit, we can run up to 8 vcpu threads from up to 4 different VMs, and we can run multiple vcores with 2 or 4 vcpus per vcore. Dynamic micro-threading is only available if the static configuration of the cores is whole-core mode (unsplit), and only on POWER8. To manage this, we introduce a new kvm_split_mode struct which is shared across all of the subcores in the core, with a pointer in the paca on each thread. In addition we extend the core_info struct to have information on each subcore. When deciding whether to add a vcore to the set already on the core, we now have two possibilities: (a) piggyback the vcore onto an existing subcore, or (b) start a new subcore. Currently, when any vcpu needs to exit the guest and switch to host virtual mode, we interrupt all the threads in all subcores and switch the core back to whole-core mode. It may be possible in future to allow some of the subcores to keep executing in the guest while subcore 0 switches to the host, but that is not implemented in this patch. This adds a module parameter called dynamic_mt_modes which controls which micro-threading (split-core) modes the code will consider, as a bitmap. In other words, if it is 0, no micro-threading mode is considered; if it is 2, only 2-way micro-threading is considered; if it is 4, only 4-way, and if it is 6, both 2-way and 4-way micro-threading mode will be considered. The default is 6. With this, we now have secondary threads which are the primary thread for their subcore and therefore need to do the MMU switch. These threads will need to be started even if they have no vcpu to run, so we use the vcore pointer in the PACA rather than the vcpu pointer to trigger them. It is now possible for thread 0 to find that an exit has been requested before it gets to switch the subcore state to the guest. In that case we haven't added the guest's timebase offset to the timebase, so we need to be careful not to subtract the offset in the guest exit path. In fact we just skip the whole path that switches back to host context, since we haven't switched to the guest context. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-30KVM: PPC: Book3S PR: Handle Facility interrupt and FSCRAlexander Graf1-0/+2
POWER8 introduced a new interrupt type called "Facility unavailable interrupt" which contains its status message in a new register called FSCR. Handle these exits and try to emulate instructions for unhandled facilities. Follow-on patches enable KVM to expose specific facilities into the guest. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-03-29KVM: PPC: Book3S HV: Save/restore host PMU registers that are new in POWER8Paul Mackerras1-1/+1
Currently we save the host PMU configuration, counter values, etc., when entering a guest, and restore it on return from the guest. (We have to do this because the guest has control of the PMU while it is executing.) However, we missed saving/restoring the SIAR and SDAR registers, as well as the registers which are new on POWER8, namely SIER and MMCR2. This adds code to save the values of these registers when entering the guest and restore them on exit. This also works around the bug in POWER8 where setting PMAE with a counter already negative doesn't generate an interrupt. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-01-29Merge branch 'kvm-ppc-next' of git://github.com/agraf/linux-2.6 into kvm-queuePaolo Bonzini1-0/+1
Conflicts: arch/powerpc/kvm/book3s_hv_rmhandlers.S arch/powerpc/kvm/booke.c
2014-01-27KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbersPaul Mackerras1-0/+1
On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-12-18powerpc: book3s: kvm: Don't abuse host r2 in exit pathAneesh Kumar K.V1-0/+1
We don't use PACATOC for PR. Avoid updating HOST_R2 with PR KVM mode when both HV and PR are enabled in the kernel. Without this we get the below crash (qemu) Unable to handle kernel paging request for data at address 0xffffffffffff8310 Faulting instruction address: 0xc00000000001d5a4 cpu 0x2: Vector: 300 (Data Access) at [c0000001dc53aef0] pc: c00000000001d5a4: .vtime_delta.isra.1+0x34/0x1d0 lr: c00000000001d760: .vtime_account_system+0x20/0x60 sp: c0000001dc53b170 msr: 8000000000009032 dar: ffffffffffff8310 dsisr: 40000000 current = 0xc0000001d76c62d0 paca = 0xc00000000fef1100 softe: 0 irq_happened: 0x01 pid = 4472, comm = qemu-system-ppc enter ? for help [c0000001dc53b200] c00000000001d760 .vtime_account_system+0x20/0x60 [c0000001dc53b290] c00000000008d050 .kvmppc_handle_exit_pr+0x60/0xa50 [c0000001dc53b340] c00000000008f51c kvm_start_lightweight+0xb4/0xc4 [c0000001dc53b510] c00000000008cdf0 .kvmppc_vcpu_run_pr+0x150/0x2e0 [c0000001dc53b9e0] c00000000008341c .kvmppc_vcpu_run+0x2c/0x40 [c0000001dc53ba50] c000000000080af4 .kvm_arch_vcpu_ioctl_run+0x54/0x1b0 [c0000001dc53bae0] c00000000007b4c8 .kvm_vcpu_ioctl+0x478/0x730 [c0000001dc53bca0] c0000000002140cc .do_vfs_ioctl+0x4ac/0x770 [c0000001dc53bd80] c0000000002143e8 .SyS_ioctl+0x58/0xb0 [c0000001dc53be30] c000000000009e58 syscall_exit+0x0/0x98 Signed-off-by: Alexander Graf <agraf@suse.de>
2013-12-09KVM: PPC: Book3S: PR: Make svcpu -> vcpu store preempt savvyAlexander Graf1-0/+1
As soon as we get back to our "highmem" handler in virtual address space we may get preempted. Today the reason we can get preempted is that we replay interrupts and all the lazy logic thinks we have interrupts enabled. However, it's not hard to make the code interruptible and that way we can enable and handle interrupts even earlier. This fixes random guest crashes that happened with CONFIG_PREEMPT=y for me. Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17kvm: powerpc: book3s: Add a new config variable CONFIG_KVM_BOOK3S_HV_POSSIBLEAneesh Kumar K.V1-1/+1
This help ups to select the relevant code in the kernel code when we later move HV and PR bits as seperate modules. The patch also makes the config options for PR KVM selectable Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17KVM: PPC: Book3S PR: Keep volatile reg values in vcpu rather than shadow_vcpuPaul Mackerras1-3/+3
Currently PR-style KVM keeps the volatile guest register values (R0 - R13, CR, LR, CTR, XER, PC) in a shadow_vcpu struct rather than the main kvm_vcpu struct. For 64-bit, the shadow_vcpu exists in two places, a kmalloc'd struct and in the PACA, and it gets copied back and forth in kvmppc_core_vcpu_load/put(), because the real-mode code can't rely on being able to access the kmalloc'd struct. This changes the code to copy the volatile values into the shadow_vcpu as one of the last things done before entering the guest. Similarly the values are copied back out of the shadow_vcpu to the kvm_vcpu immediately after exiting the guest. We arrange for interrupts to be still disabled at this point so that we can't get preempted on 64-bit and end up copying values from the wrong PACA. This means that the accessor functions in kvm_book3s.h for these registers are greatly simplified, and are same between PR and HV KVM. In places where accesses to shadow_vcpu fields are now replaced by accesses to the kvm_vcpu, we can also remove the svcpu_get/put pairs. Finally, on 64-bit, we don't need the kmalloc'd struct at all any more. With this, the time to read the PVR one million times in a loop went from 567.7ms to 575.5ms (averages of 6 values), an increase of about 1.4% for this worse-case test for guest entries and exits. The standard deviation of the measurements is about 11ms, so the difference is only marginally significant statistically. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17KVM: PPC: Book3S HV: Add support for guest Program Priority RegisterPaul Mackerras1-0/+1
POWER7 and later IBM server processors have a register called the Program Priority Register (PPR), which controls the priority of each hardware CPU SMT thread, and affects how fast it runs compared to other SMT threads. This priority can be controlled by writing to the PPR or by use of a set of instructions of the form or rN,rN,rN which are otherwise no-ops but have been defined to set the priority to particular levels. This adds code to context switch the PPR when entering and exiting guests and to make the PPR value accessible through the SET/GET_ONE_REG interface. When entering the guest, we set the PPR as late as possible, because if we are setting a low thread priority it will make the code run slowly from that point on. Similarly, the first-level interrupt handlers save the PPR value in the PACA very early on, and set the thread priority to the medium level, so that the interrupt handling code runs at a reasonable speed. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26KVM: PPC: Book3S HV: Speed up wakeups of CPUs on HV KVMBenjamin Herrenschmidt1-1/+7
Currently, we wake up a CPU by sending a host IPI with smp_send_reschedule() to thread 0 of that core, which will take all threads out of the guest, and cause them to re-evaluate their interrupt status on the way back in. This adds a mechanism to differentiate real host IPIs from IPIs sent by KVM for guest threads to poke each other, in order to target the guest threads precisely when possible and avoid that global switch of the core to host state. We then use this new facility in the in-kernel XICS code. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-02-15powerpc/kvm/book3s_hv: Preserve guest CFAR register valuePaul Mackerras1-0/+3
The CFAR (Come-From Address Register) is a useful debugging aid that exists on POWER7 processors. Currently HV KVM doesn't save or restore the CFAR register for guest vcpus, making the CFAR of limited use in guests. This adds the necessary code to capture the CFAR value saved in the early exception entry code (it has to be saved before any branch is executed), save it in the vcpu.arch struct, and restore it on entry to the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-09-07powerpc: Restore VDSO information on critical exception om BookEMihai Caraman1-1/+0
Critical exception on 64-bit booke uses user-visible SPRG3 as scratch. Restore VDSO information in SPRG3 on exception prolog. Use a common sprg3 field in PACA for all powerpc64 architectures. Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-11powerpc: Add VDSO version of getcpuAnton Blanchard1-0/+1
We have a request for a fast method of getting CPU and NUMA node IDs from userspace. This patch implements a getcpu VDSO function, similar to x86. Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be modified by a KVM guest, so we save the SPRG3 value in the paca and restore it when transitioning from the guest to the host. I have a glibc patch that implements sched_getcpu on top of this. Testing on a POWER7: baseline: 538 cycles vdso: 30 cycles Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-08KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIsPaul Mackerras1-0/+8
Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode codePaul Mackerras1-0/+1
With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-09-25KVM: PPC: book3s_pr: Simplify transitions between virtual and real modePaul Mackerras1-0/+1
This simplifies the way that the book3s_pr makes the transition to real mode when entering the guest. We now call kvmppc_entry_trampoline (renamed from kvmppc_rmcall) in the base kernel using a normal function call instead of doing an indirect call through a pointer in the vcpu. If kvm is a module, the module loader takes care of generating a trampoline as it does for other calls to functions outside the module. kvmppc_entry_trampoline then disables interrupts and jumps to kvmppc_handler_trampoline_enter in real mode using an rfi[d]. That then uses the link register as the address to return to (potentially in module space) when the guest exits. This also simplifies the way that we call the Linux interrupt handler when we exit the guest due to an external, decrementer or performance monitor interrupt. Instead of turning on the MMU, then deciding that we need to call the Linux handler and turning the MMU back off again, we now go straight to the handler at the point where we would turn the MMU on. The handler will then return to the virtual-mode code (potentially in the module). Along the way, this moves the setting and clearing of the HID5 DCBZ32 bit into real-mode interrupts-off code, and also makes sure that we clear the MSR[RI] bit before loading values into SRR0/1. The net result is that we no longer need any code addresses to be stored in vcpu->arch. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-12KVM: PPC: book3s_hv: Add support for PPC970-family processorsPaul Mackerras1-1/+1
This adds support for running KVM guests in supervisor mode on those PPC970 processors that have a usable hypervisor mode. Unfortunately, Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to 1), but the YDL PowerStation does have a usable hypervisor mode. There are several differences between the PPC970 and POWER7 in how guests are managed. These differences are accommodated using the CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature bits. Notably, on PPC970: * The LPCR, LPID or RMOR registers don't exist, and the functions of those registers are provided by bits in HID4 and one bit in HID0. * External interrupts can be directed to the hypervisor, but unlike POWER7 they are masked by MSR[EE] in non-hypervisor modes and use SRR0/1 not HSRR0/1. * There is no virtual RMA (VRMA) mode; the guest must use an RMO (real mode offset) area. * The TLB entries are not tagged with the LPID, so it is necessary to flush the whole TLB on partition switch. Furthermore, when switching partitions we have to ensure that no other CPU is executing the tlbie or tlbsync instructions in either the old or the new partition, otherwise undefined behaviour can occur. * The PMU has 8 counters (PMC registers) rather than 6. * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist. * The SLB has 64 entries rather than 32. * There is no mediated external interrupt facility, so if we switch to a guest that has a virtual external interrupt pending but the guest has MSR[EE] = 0, we have to arrange to have an interrupt pending for it so that we can get control back once it re-enables interrupts. We do that by sending ourselves an IPI with smp_send_reschedule after hard-disabling interrupts. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-12KVM: PPC: Allow book3s_hv guests to use SMT processor modesPaul Mackerras1-0/+2
This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-12KVM: PPC: Add support for Book3S processors in hypervisor modePaul Mackerras1-0/+12
This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-12KVM: PPC: Split host-state fields out of kvmppc_book3s_shadow_vcpuPaul Mackerras1-8/+19
There are several fields in struct kvmppc_book3s_shadow_vcpu that temporarily store bits of host state while a guest is running, rather than anything relating to the particular guest or vcpu. This splits them out into a new kvmppc_host_state structure and modifies the definitions in asm-offsets.c to suit. On 32-bit, we have a kvmppc_host_state structure inside the kvmppc_book3s_shadow_vcpu since the assembly code needs to be able to get to them both with one pointer. On 64-bit they are separate fields in the PACA. This means that on 64-bit we don't need to copy the kvmppc_host_state in and out on vcpu load/unload, and in future will mean that the book3s_hv code doesn't need a shadow_vcpu struct in the PACA at all. That does mean that we have to be careful not to rely on any values persisting in the hstate field of the paca across any point where we could block or get preempted. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-04-20powerpc: Base support for exceptions using HSRR0/1Benjamin Herrenschmidt1-0/+1
Pass the register type to the prolog, also provides alternate "HV" version of hardware interrupt (0x500) and adjust LPES accordingly We tag those interrupts by setting bit 0x2 in the trap number Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-05-17KVM: PPC: Use KVM_BOOK3S_HANDLERAlexander Graf1-2/+2
So far we had a lot of conditional code on CONFIG_KVM_BOOK3S_64_HANDLER. As we're moving towards common code between 32 and 64 bits, most of these ifdefs can be moved to a more generic term define, called CONFIG_KVM_BOOK3S_HANDLER. This patch adds the new generic config option and moves ifdefs over. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: PPC: Add fields to shadow vcpuAlexander Graf1-0/+21
After a lot of thought on how to make the entry / exit code easier, I figured it'd be clever to put even more register state into the shadow vcpu. That way we have more registers available to use, making the code easier to read. So this patch adds a few new fields to that shadow vcpu. Later on we will remove the originals from the vcpu and paca. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: PPC: Name generic 64-bit code genericAlexander Graf1-0/+76
We have quite some code that can be used by Book3S_32 and Book3S_64 alike, so let's call it "Book3S" instead of "Book3S_64", so we can later on use it from the 32 bit port too. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>