This is a note to let you know that I've just added the patch titled
Revert "KVM: x86/pmu: Accept 0 for absent PMU MSRs when host-initiated if !enable_pmu"
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-kvm-x86-pmu-accept-0-for-absent-pmu-msrs-when.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b158536de85c5edd2ddde0f2d4b65a17607c72e0
Author: Sean Christopherson <seanjc@xxxxxxxxxx>
Date: Sat Jun 11 00:57:51 2022 +0000
Revert "KVM: x86/pmu: Accept 0 for absent PMU MSRs when host-initiated if !enable_pmu"
[ Upstream commit 5d4283df5a0fc8299fba9443c33d219939eccc2d ]
Eating reads and writes to all "PMU" MSRs when there is no PMU is wildly
broken as it results in allowing accesses to _any_ MSR on Intel CPUs
as intel_is_valid_msr() returns true for all host_initiated accesses.
A revert of commit d1c88a402056 ("KVM: x86: always allow host-initiated
writes to PMU MSRs") will soon follow.
This reverts commit 8e6a58e28b34e8d247e772159b8fa8f6bae39192.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Message-Id: <20220611005755.753273-4-seanjc@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 2334ddfbbab2..3f868fed9114 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -433,19 +433,11 @@ 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 d93ecb25fe17..136039fc6d01 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -232,16 +232,7 @@ 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. */
- 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;
- }
+ return false;
}
static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, u32 msr)
