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    Subject[PATCH 5.19 1105/1157] KVM: x86/pmu: Accept 0 for absent PMU MSRs when host-initiated if !enable_pmu
    Date
    From: Like Xu <likexu@tencent.com>

    [ Upstream commit 8e6a58e28b34e8d247e772159b8fa8f6bae39192 ]

    Whenever an MSR is part of KVM_GET_MSR_INDEX_LIST, as is the case for
    MSR_K7_EVNTSEL0 or MSR_F15H_PERF_CTL0, it has to be always retrievable
    and settable with KVM_GET_MSR and KVM_SET_MSR.

    Accept a zero value for these MSRs to obey the contract.

    Signed-off-by: Like Xu <likexu@tencent.com>
    Message-Id: <20220601031925.59693-1-likexu@tencent.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/x86/kvm/pmu.c | 8 ++++++++
    arch/x86/kvm/svm/pmu.c | 11 ++++++++++-
    2 files changed, 18 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
    index 3f868fed9114..2334ddfbbab2 100644
    --- a/arch/x86/kvm/pmu.c
    +++ b/arch/x86/kvm/pmu.c
    @@ -433,11 +433,19 @@ static void kvm_pmu_mark_pmc_in_use(struct kvm_vcpu *vcpu, u32 msr)

    int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
    {
    + if (msr_info->host_initiated && !vcpu->kvm->arch.enable_pmu) {
    + msr_info->data = 0;
    + return 0;
    + }
    +
    return static_call(kvm_x86_pmu_get_msr)(vcpu, msr_info);
    }

    int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
    {
    + if (msr_info->host_initiated && !vcpu->kvm->arch.enable_pmu)
    + return !!msr_info->data;
    +
    kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index);
    return static_call(kvm_x86_pmu_set_msr)(vcpu, msr_info);
    }
    diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
    index 136039fc6d01..d93ecb25fe17 100644
    --- a/arch/x86/kvm/svm/pmu.c
    +++ b/arch/x86/kvm/svm/pmu.c
    @@ -232,7 +232,16 @@ static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu,
    static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
    {
    /* All MSRs refer to exactly one PMC, so msr_idx_to_pmc is enough. */
    - return false;
    + if (!host_initiated)
    + return false;
    +
    + switch (msr) {
    + case MSR_K7_EVNTSEL0 ... MSR_K7_PERFCTR3:
    + case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5:
    + return true;
    + default:
    + return false;
    + }
    }

    static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
    --
    2.35.1


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