Re: [PATCH v11 00/11] Guest Last Branch Recording Enabling

Xu, Like
2020-05-27T08:28:22Z

Hi Paolo,

On 2020/5/14 16:30, Like Xu wrote:
> Hi Peter,
> Would you mind acking the host perf patches if it looks good to you ?
>
> Hi Paolo,
> Please help review the KVM proposal changes in this stable version.
>
> Now, we can use upstream QEMU w/ '-cpu host' to test this feature, and
> disable it by clearing the LBR format bits in the IA32_PERF_CAPABILITIES.
>
> v10->v11 Changelog:
> - add '.config = INTEL_FIXED_VLBR_EVENT' to the guest LBR event config;
> - rewrite is_guest_lbr_event() with 'config == INTEL_FIXED_VLBR_EVENT';
> - emit pr_warn() on the host when guest LBR is temporarily unavailable;
> - drop the KVM_CAP_X86_GUEST_LBR patch;
> - rewrite MSR_IA32_PERF_CAPABILITIES patch LBR record format;
> - split 'kvm_pmu->lbr_already_available' into a separate patch;
> - split 'pmu_ops->availability_check' into a separate patch;
> - comments and naming refinement, misc;
>
> You may check more details in each commit.
>
> Previous:
> https://lore.kernel.org/kvm/20200423081412.164863-1-like.xu@linux.intel.com/
...
>
> Like Xu (9):
> perf/x86/core: Refactor hw->idx checks and cleanup
> perf/x86/lbr: Add interface to get basic information about LBR stack
> perf/x86: Add constraint to create guest LBR event without hw counter
> perf/x86: Keep LBR stack unchanged in host context for guest LBR event
Do you have a moment to review the KVM changes in this version
to enable guest LBR on most Intel platforms ?

It would be great if I can address most of your comments in the next version.

Thanks,
Like Xu
> KVM: x86: Expose MSR_IA32_PERF_CAPABILITIES for LBR record format
> KVM: x86/pmu: Emulate LBR feature via guest LBR event
> KVM: x86/pmu: Release guest LBR event via vPMU lazy release mechanism
> KVM: x86/pmu: Check guest LBR availability in case host reclaims them
> KVM: x86/pmu: Reduce the overhead of LBR passthrough or cancellation
>
> Wei Wang (2):
> perf/x86: Fix variable types for LBR registers
> KVM: x86/pmu: Tweak kvm_pmu_get_msr to pass 'struct msr_data' in
>
> arch/x86/events/core.c | 26 ++-
> arch/x86/events/intel/core.c | 105 ++++++----
> arch/x86/events/intel/lbr.c | 56 +++++-
> arch/x86/events/perf_event.h | 12 +-
> arch/x86/include/asm/kvm_host.h | 13 ++
> arch/x86/include/asm/perf_event.h | 34 +++-
> arch/x86/kvm/cpuid.c | 2 +-
> arch/x86/kvm/pmu.c | 19 +-
> arch/x86/kvm/pmu.h | 15 +-
> arch/x86/kvm/svm/pmu.c | 7 +-
> arch/x86/kvm/vmx/capabilities.h | 15 ++
> arch/x86/kvm/vmx/pmu_intel.c | 320 +++++++++++++++++++++++++++++-
> arch/x86/kvm/vmx/vmx.c | 12 +-
> arch/x86/kvm/vmx/vmx.h | 2 +
> arch/x86/kvm/x86.c | 18 +-
> 15 files changed, 564 insertions(+), 92 deletions(-)
>