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    Subject[PATCH v2 14/15] KVM: x86: Add Arch LBR data MSR access interface
    Date
    Arch LBR MSRs are xsave-supported, but they're operated as "independent"
    xsave feature by PMU code, i.e., during thread/process context switch,
    the MSRs are saved/restored with perf_event_task_sched_{in|out} instead
    of generic kernel fpu switch code, i.e.,save_fpregs_to_fpstate() and
    restore_fpregs_from_fpstate(). When vcpu guest/host fpu state swap happens,
    Arch LBR MSRs are retained so they can be accessed directly.

    Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
    Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
    ---
    arch/x86/kvm/vmx/pmu_intel.c | 10 ++++++++++
    1 file changed, 10 insertions(+)

    diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
    index b57944d5e7d8..241128972776 100644
    --- a/arch/x86/kvm/vmx/pmu_intel.c
    +++ b/arch/x86/kvm/vmx/pmu_intel.c
    @@ -410,6 +410,11 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
    msr_info->data = vmcs_read64(GUEST_IA32_LBR_CTL);
    }
    return 0;
    + case MSR_ARCH_LBR_FROM_0 ... MSR_ARCH_LBR_FROM_0 + 31:
    + case MSR_ARCH_LBR_TO_0 ... MSR_ARCH_LBR_TO_0 + 31:
    + case MSR_ARCH_LBR_INFO_0 ... MSR_ARCH_LBR_INFO_0 + 31:
    + rdmsrl(msr_info->index, msr_info->data);
    + return 0;
    default:
    if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
    (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
    @@ -528,6 +533,11 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
    (data & ARCH_LBR_CTL_LBREN))
    intel_pmu_create_guest_lbr_event(vcpu);
    return 0;
    + case MSR_ARCH_LBR_FROM_0 ... MSR_ARCH_LBR_FROM_0 + 31:
    + case MSR_ARCH_LBR_TO_0 ... MSR_ARCH_LBR_TO_0 + 31:
    + case MSR_ARCH_LBR_INFO_0 ... MSR_ARCH_LBR_INFO_0 + 31:
    + wrmsrl(msr_info->index, msr_info->data);
    + return 0;
    default:
    if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) ||
    (pmc = get_gp_pmc(pmu, msr, MSR_IA32_PMC0))) {
    --
    2.27.0
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