Revert "KVM: x86: always allow host-initiated writes to PMU MSRs"

Revert the hack to allow host-initiated accesses to all "PMU" MSRs,
as intel_is_valid_msr() returns true for _all_ MSRs, regardless of whether
or not it has a snowball's chance in hell of actually being a PMU MSR.

That mostly gets papered over by the actual get/set helpers only handling
MSRs that they knows about, except there's the minor detail that
kvm_pmu_{g,s}et_msr() eat reads and writes when the PMU is disabled.
I.e. KVM will happy allow reads and writes to _any_ MSR if the PMU is
disabled, either via module param or capability.

This reverts commit d1c88a4020567ba4da52f778bcd9619d87e4ea75.

Fixes: d1c88a402056 ("KVM: x86: always allow host-initiated writes to PMU MSRs")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220611005755.753273-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 256244b8f89c..f24613a108c5 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -179,7 +179,7 @@ static struct kvm_pmc *amd_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu,
 	return &counters[idx];
 }
 
-static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr, bool host_initiated)
+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;