Last Branch Recording (LBR) is a performance monitor unit (PMU) feature
on Intel CPUs that captures branch related info. This patch series enables
this feature to KVM guests.
Here is a conclusion of the fundamental methods that we use:
1) the LBR feature is enabled per guest via QEMU setting of
KVM_CAP_X86_GUEST_LBR;
2) the LBR stack is passed through to the guest for direct accesses after
the guest's first access to any of the lbr related MSRs;
3) the host will help save/resotre the LBR stack when the vCPU is
scheduled out/in.
ChangeLog:
- KVM/x86:
- patch 4: enable guest lbr when guest lbr msr index and host
lbr msr index matches;
- patch 5: change kvm_pmu_get_msr to get the msr_data struct;
- patch 8: remove the PF_VCPU and is_kernel_event check;
- patch 10:
- move the lbr virtualization code from vmx.c to pmu_intel.c;
- save the lbr stack even when the guest is not using the user
callstack mode in case some tools (e.g. autofdo) complain
for bogus samples;
- patch 11: remove the common handling of the debugctl;
- patch 12: support to report GLOBAL_STATUS_LBRS_FROZEN.
previous:
https://lkml.org/lkml/2018/12/26/82
Like Xu (1):
KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr
stack
Wei Wang (11):
perf/x86: fix the variable type of the LBR MSRs
perf/x86: add a function to get the lbr stack
KVM/x86: KVM_CAP_X86_GUEST_LBR
KVM/x86: intel_pmu_lbr_enable
KVM/x86/vPMU: tweak kvm_pmu_get_msr
KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest
perf/x86: no counter allocation support
perf/x86: save/restore LBR_SELECT on vCPU switching
KVM/x86/lbr: lazy save the guest lbr stack
KVM/x86: remove the common handling of the debugctl msr
KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN
arch/x86/events/core.c | 12 ++
arch/x86/events/intel/lbr.c | 42 +++-
arch/x86/events/perf_event.h | 6 +-
arch/x86/include/asm/kvm_host.h | 5 +
arch/x86/include/asm/perf_event.h | 16 ++
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/cpuid.h | 8 +
arch/x86/kvm/pmu.c | 18 +-
arch/x86/kvm/pmu.h | 11 +-
arch/x86/kvm/pmu_amd.c | 7 +-
arch/x86/kvm/vmx/pmu_intel.c | 398 +++++++++++++++++++++++++++++++++++++-
arch/x86/kvm/vmx/vmx.c | 4 +-
arch/x86/kvm/vmx/vmx.h | 2 +
arch/x86/kvm/x86.c | 33 ++--
include/linux/perf_event.h | 5 +
include/uapi/linux/kvm.h | 1 +
include/uapi/linux/perf_event.h | 3 +-
17 files changed, 535 insertions(+), 38 deletions(-)
--
2.7.4
