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    SubjectRe: [RFC PATCH 34/41] KVM: x86/pmu: Intercept EVENT_SELECT MSR
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    On Fri, Jan 26, 2024, Xiong Zhang wrote:
    > From: Xiong Zhang <xiong.y.zhang@intel.com>
    >
    > Event selectors for GP counters are still intercepted for the purpose of
    > security, i.e., preventing guest from using unallowed events to steal
    > information or take advantages of any CPU errata.

    Heh, so then they shouldn't have been passed through in the first place.

    > Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
    > Signed-off-by: Mingwei Zhang <mizhang@google.com>
    > ---
    > arch/x86/kvm/vmx/pmu_intel.c | 1 -
    > arch/x86/kvm/vmx/vmx.c | 1 -
    > 2 files changed, 2 deletions(-)
    >
    > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
    > index 9bbd5084a766..621922005184 100644
    > --- a/arch/x86/kvm/vmx/pmu_intel.c
    > +++ b/arch/x86/kvm/vmx/pmu_intel.c
    > @@ -809,7 +809,6 @@ void intel_passthrough_pmu_msrs(struct kvm_vcpu *vcpu)
    > int i;
    >
    > for (i = 0; i < vcpu_to_pmu(vcpu)->nr_arch_gp_counters; i++) {
    > - vmx_set_intercept_for_msr(vcpu, MSR_ARCH_PERFMON_EVENTSEL0 + i, MSR_TYPE_RW, false);
    > vmx_set_intercept_for_msr(vcpu, MSR_IA32_PERFCTR0 + i, MSR_TYPE_RW, false);
    > if (fw_writes_is_enabled(vcpu))
    > vmx_set_intercept_for_msr(vcpu, MSR_IA32_PMC0 + i, MSR_TYPE_RW, false);
    > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
    > index d28afa87be70..1a518800d154 100644
    > --- a/arch/x86/kvm/vmx/vmx.c
    > +++ b/arch/x86/kvm/vmx/vmx.c
    > @@ -698,7 +698,6 @@ static bool is_valid_passthrough_msr(u32 msr)
    > case MSR_LBR_CORE_FROM ... MSR_LBR_CORE_FROM + 8:
    > case MSR_LBR_CORE_TO ... MSR_LBR_CORE_TO + 8:
    > /* LBR MSRs. These are handled in vmx_update_intercept_for_lbr_msrs() */
    > - case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 7:
    > case MSR_IA32_PMC0 ... MSR_IA32_PMC0 + 7:
    > case MSR_IA32_PERFCTR0 ... MSR_IA32_PERFCTR0 + 7:
    > case MSR_CORE_PERF_FIXED_CTR_CTRL:
    > --
    > 2.34.1
    >

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