- 16 Jan, 2018 6 commits
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Paolo Bonzini authored
xsetbv can be expensive when running on nested virtualization, try to avoid it. Reviewed-by:
Jim Mattson <jmattson@google.com> Reviewed-by:
Wanpeng Li <wanpeng.li@hotmail.com> Reviewed-by:
Quan Xu <quan.xu0@gmail.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com>
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Wanpeng Li authored
syzkaller reported: WARNING: CPU: 0 PID: 12927 at arch/x86/kernel/traps.c:780 do_debug+0x222/0x250 CPU: 0 PID: 12927 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #16 RIP: 0010:do_debug+0x222/0x250 Call Trace: <#DB> debug+0x3e/0x70 RIP: 0010:copy_user_enhanced_fast_string+0x10/0x20 </#DB> _copy_from_user+0x5b/0x90 SyS_timer_create+0x33/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The testcase sets a watchpoint (with perf_event_open) on a buffer that is passed to timer_create() as the struct sigevent argument. In timer_create(), copy_from_user()'s rep movsb triggers the BP. The testcase also sets the debug registers for the guest. However, KVM only restores host debug registers when the host has active watchpoints, which triggers a race condition when running the testcase with multiple threads. The guest's DR6.BS bit can escape to the host before another thread invokes timer_create(), and do_debug() complains. The fix is to respect do_debug()'s dr6 invariant when leaving KVM. Reported-by:Dmitry Vyukov <dvyukov@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Reviewed-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
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Wanpeng Li authored
When running on a virtual machine, IPIs are expensive when the target CPU is sleeping. Thus, it is nice to be able to avoid them for TLB shootdowns. KVM can just do the flush via INVVPID on the guest's behalf the next time the CPU is scheduled. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
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Wanpeng Li authored
Introduce a new bool invalidate_gpa argument to kvm_x86_ops->tlb_flush, it will be used by later patches to just flush guest tlb. For VMX, this will use INVVPID instead of INVEPT, which will invalidate combined mappings while keeping guest-physical mappings. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
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Wanpeng Li authored
Remote TLB flush does a busy wait which is fine in bare-metal scenario. But with-in the guest, the vcpus might have been pre-empted or blocked. In this scenario, the initator vcpu would end up busy-waiting for a long amount of time; it also consumes CPU unnecessarily to wake up the target of the shootdown. This patch set adds support for KVM's new paravirtualized TLB flush; remote TLB flush does not wait for vcpus that are sleeping, instead KVM will flush the TLB as soon as the vCPU starts running again. The improvement is clearly visible when the host is overcommitted; in this case, the PV TLB flush (in addition to avoiding the wait on the main CPU) prevents preempted vCPUs from stealing precious execution time from the running ones. Testing on a Xeon Gold 6142 2.6GHz 2 sockets, 32 cores, 64 threads, so 64 pCPUs, and each VM is 64 vCPUs. ebizzy -M vanilla optimized boost 1VM 46799 48670 4% 2VM 23962 42691 78% 3VM 16152 37539 132% Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: -
Wanpeng Li authored
The next patch will add another bit to the preempted field in kvm_steal_time. Define a constant for bit 0 (the only one that is currently used). Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
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- 14 Dec, 2017 34 commits
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Paolo Bonzini authored
After the vcpu_load/vcpu_put pushdown, the handling of asynchronous VCPU ioctl is already much clearer in that it is obvious that they bypass vcpu_load and vcpu_put. However, it is still not perfect in that the different state of the VCPU mutex is still hidden in the caller. Separate those ioctls into a new function kvm_arch_vcpu_async_ioctl that returns -ENOIOCTLCMD for more "traditional" synchronous ioctls. Cc: James Hogan <jhogan@kernel.org> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:
Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by:
Cornelia Huck <cohuck@redhat.com> Suggested-by:
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Christoffer Dall authored
Move the calls to vcpu_load() and vcpu_put() in to the architecture specific implementations of kvm_arch_vcpu_ioctl() which dispatches further architecture-specific ioctls on to other functions. Some architectures support asynchronous vcpu ioctls which cannot call vcpu_load() or take the vcpu->mutex, because that would prevent concurrent execution with a running VCPU, which is the intended purpose of these ioctls, for example because they inject interrupts. We repeat the separate checks for these specifics in the architecture code for MIPS, S390 and PPC, and avoid taking the vcpu->mutex and calling vcpu_load for these ioctls. Signed-off-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_set_fpu(). Reviewed-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_get_fpu(). Reviewed-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_set_guest_debug(). Reviewed-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_translate(). Reviewed-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_set_mpstate(). Reviewed-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_get_mpstate(). Reviewed-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_set_sregs(). Signed-off-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_get_sregs(). Signed-off-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_set_regs(). Signed-off-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_get_regs(). Signed-off-by:
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Christoffer Dall authored
Move vcpu_load() and vcpu_put() into the architecture specific implementations of kvm_arch_vcpu_ioctl_run(). Signed-off-by:
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Christoffer Dall authored
In preparation for moving calls to vcpu_load() and vcpu_put() into the architecture specific implementations of the KVM vcpu ioctls, move the calls in the main kvm_vcpu_ioctl() dispatcher function to each case of the ioctl select statement. This allows us to move the vcpu_load() and vcpu_put() calls into architecture specific implementations of vcpu ioctls, one by one. Reviewed-by:
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Christoffer Dall authored
As we're about to call vcpu_load() from architecture-specific implementations of the KVM vcpu ioctls, but yet we access data structures protected by the vcpu->mutex in the generic code, factor this logic out from vcpu_load(). x86 is the only architecture which calls vcpu_load() outside of the main vcpu ioctl function, and these calls will no longer take the vcpu mutex following this patch. However, with the exception of kvm_arch_vcpu_postcreate (see below), the callers are either in the creation or destruction path of the VCPU, which means there cannot be any concurrent access to the data structure, because the file descriptor is not yet accessible, or is already gone. kvm_arch_vcpu_postcreate makes the newly created vcpu potentially accessible by other in-kernel threads through the kvm->vcpus array, and we therefore take the vcpu mutex in this case directly. Signed-off-by:
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Quan Xu authored
Since KVM removes the only I/O port 0x80 bypass on Intel hosts, clear CPU_BASED_USE_IO_BITMAPS and set CPU_BASED_UNCOND_IO_EXITING bit. Then these I/O permission bitmaps are not used at all, so drop I/O permission bitmaps. Signed-off-by:
™ <rkrcmar@redhat.com> Signed-off-by: -
Wanpeng Li authored
When I run ebizzy in a 32 vCPUs guest on a 32 pCPUs Xeon box, I can observe ~8000 kvm_wait_lapic_expire CurAvg/s through kvm_stat tool even if the advance tscdeadline hrtimer expiration is disabled. Each call to wait_lapic_expire() will consume ~70 cycles when a timer fires since apic_timer_expire() will set expired_tscdeadline and then wait_lapic_expire() will do some caculation before bailing out. So total ~175us per second is lost on this 3.2Ghz machine. This patch reduces the overhead by skipping the function wait_lapic_expire() when lapic_timer_advance is disabled. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by:
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Wanpeng Li authored
MSR_IA32_DEBUGCTLMSR is zeroed on VMEXIT, so it is saved/restored each time during world switch. This patch caches the host IA32_DEBUGCTL MSR and saves/restores the host IA32_DEBUGCTL msr when guest/host switches to avoid to save/restore each time during world switch. This saves about 100 clock cycles per vmexit. Suggested-by:
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Mark Kanda authored
When attempting to free a loaded VMCS02, add a WARN and avoid freeing it (to avoid use-after-free situations). Suggested-by:
Mark Kanda <mark.kanda@oracle.com> Reviewed-by:
Ameya More <ameya.more@oracle.com> Reviewed-by:
Krish Sadhukhan <krish.sadhukhan@oracle.com> Reviewed-by:
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Jim Mattson authored
The potential performance advantages of a vmcs02 pool have never been realized. To simplify the code, eliminate the pool. Instead, a single vmcs02 is allocated per VCPU when the VCPU enters VMX operation. Signed-off-by:
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Yang Zhong authored
Intel IceLake cpu has added new cpu features,AVX512_VBMI2/GFNI/ VAES/VPCLMULQDQ/AVX512_VNNI/AVX512_BITALG. Those new cpu features need expose to guest VM. The bit definition: CPUID.(EAX=7,ECX=0):ECX[bit 06] AVX512_VBMI2 CPUID.(EAX=7,ECX=0):ECX[bit 08] GFNI CPUID.(EAX=7,ECX=0):ECX[bit 09] VAES CPUID.(EAX=7,ECX=0):ECX[bit 10] VPCLMULQDQ CPUID.(EAX=7,ECX=0):ECX[bit 11] AVX512_VNNI CPUID.(EAX=7,ECX=0):ECX[bit 12] AVX512_BITALG The release document ref below link: https://software.intel.com/sites/default/files/managed/c5/15/\ architecture-instruction-set-extensions-programming-reference.pdf The kernel dependency commit in kvm.git: (c128dbfa) Signed-off-by:
Yang Zhong <yang.zhong@intel.com> Signed-off-by:
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Markus Elfring authored
Add a jump target so that a bit of exception handling can be better reused at the end of this function. This issue was detected by using the Coccinelle software. Signed-off-by:
Markus Elfring <elfring@users.sourceforge.net> Signed-off-by:
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Liran Alon authored
This MSR returns the number of #SMIs that occurred on CPU since boot. It was seen to be used frequently by ESXi guest. Patch adds a new vcpu-arch specific var called smi_count to save the number of #SMIs which occurred on CPU since boot. It is exposed as a read-only MSR to guest (causing #GP on wrmsr) in RDMSR/WRMSR emulation code. MSR_SMI_COUNT is also added to emulated_msrs[] to make sure user-space can save/restore it for migration purposes. Signed-off-by:
Liran Alon <liran.alon@oracle.com> Suggested-by:
Nikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by:
Bhavesh Davda <bhavesh.davda@oracle.com> Signed-off-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by:
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Radim Krčmář authored
If Intel/AMD implements MWAIT, we expect that it works well and only reject known bugs; no reason to do it the other way around for minor vendors. (Not that they are relevant ATM.) This allows further simplification of kvm_mwait_in_guest(). And use boot_cpu_has() instead of "cpu_has(&boot_cpu_data," while at it. Reviewed-by:
Alexander Graf <agraf@suse.de> Acked-by:
Borislav Petkov <bp@suse.de> Acked-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
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Radim Krčmář authored
The check was added in some iteration while trying to fix a reported OS X on Core 2 bug, but that bug is elsewhere. The comment is misleading because the guest can call MWAIT with ECX = 0 even if we enforce CPUID5_ECX_INTERRUPT_BREAK; the call would have the exactly the same effect as if the host didn't have the feature. A problem is that a QEMU feature exposes CPUID5_ECX_INTERRUPT_BREAK on CPUs that do not support it. Removing the check changes behavior on last Pentium 4 lines (Presler, Dempsey, and Tulsa, which had VMX and MONITOR while missing INTERRUPT_BREAK) when running a guest OS that uses MWAIT without checking for its presence (QEMU doesn't expose MONITOR). The only known OS that ignores the MONITOR flag is old Mac OS X and we allowed it to bug on Core 2 (MWAIT used to throw #UD and only that OS noticed), so we can save another 20 lines letting it bug on even older CPUs. Alternatively, we can return MWAIT exiting by default and let userspace toggle it. Reviewed-by:
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Radim Krčmář authored
The bug prevents MWAIT from waking up after a write to the monitored cache line. KVM might emulate a CPU model that shouldn't have the bug, so the guest would not employ a workaround and possibly miss wakeups. Better to avoid the situation. Reviewed-by:
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Colin Ian King authored
The array audit_point_name is local to the source and does not need to be in global scope, so make it static. Cleans up sparse warning: arch/x86/kvm/mmu_audit.c:22:12: warning: symbol 'audit_point_name' was not declared. Should it be static? Signed-off-by:
Colin Ian King <colin.king@canonical.com> Signed-off-by:
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Gimcuan Hui authored
The kvm_mmu_clear_all_pte_masks interface is only used by kvm_mmu_module_init locally, and does not need to be called by other module, make it static. This patch cleans up sparse warning: symbol 'kvm_mmu_clear_all_pte_masks' was not declared. Should it be static? Signed-off-by:
Gimcuan Hui <gimcuan@gmail.com> Reviewed-by:
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Paolo Bonzini authored
This is encoded as F3 0F C7 /7 with a register argument. The register argument is the second array in the group9 GroupDual, while F3 is the fourth element of a Prefix. Reviewed-by:
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Paolo Bonzini authored
UMIP can be emulated almost perfectly on Intel processor by enabling descriptor-table exits. SMSW does not cause a vmexit and hence it cannot be changed into a #GP fault, but all in all it's the most "innocuous" of the unprivileged instructions that UMIP blocks. In fact, Linux is _also_ emulating SMSW instructions on behalf of the program that executes them, because some 16-bit programs expect to use SMSW to detect vm86 mode, so this is an even smaller issue. Reviewed-by:
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Paolo Bonzini authored
The User-Mode Instruction Prevention feature present in recent Intel processor prevents a group of instructions (sgdt, sidt, sldt, smsw, and str) from being executed with CPL > 0. Otherwise, a general protection fault is issued. UMIP instructions in general are also able to trigger vmexits, so we can actually emulate UMIP on older processors. This commit sets up the infrastructure so that kvm-intel.ko and kvm-amd.ko can set the UMIP feature bit for CPUID even if the feature is not actually available in hardware. Reviewed-by:
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Paolo Bonzini authored
These are needed to handle the descriptor table vmexits when emulating UMIP. Reviewed-by:
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Paolo Bonzini authored
Add the CPUID bits, make the CR4.UMIP bit not reserved anymore, and add UMIP support for instructions that are already emulated by KVM. Reviewed-by:
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Stefan Raspl authored
Add a line for the total number of events and current average at the bottom of the body. Note that both values exclude child trace events. I.e. if drilldown is activated via interactive command 'x', only the totals are accounted, or we'd be counting these twice (see previous commit "tools/kvm_stat: fix child trace events accounting"). Signed-off-by:
Stefan Raspl <raspl@linux.vnet.ibm.com> Signed-off-by:
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