[PATCH 5.10 508/545] KVM: VMX: Mark all PERF_GLOBAL_(OVF)_CTRL bits reserved if theres no vPMU

Greg Kroah-Hartman
2022-08-19T16:52:30Z

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 93255bf92939d948bc86d81c6bb70bb0fecc5db1 ]

Mark all MSR_CORE_PERF_GLOBAL_CTRL and MSR_CORE_PERF_GLOBAL_OVF_CTRL bits
as reserved if there is no guest vPMU. The nVMX VM-Entry consistency
checks do not check for a valid vPMU prior to consuming the masks via
kvm_valid_perf_global_ctrl(), i.e. may incorrectly allow a non-zero mask
to be loaded via VM-Enter or VM-Exit (well, attempted to be loaded, the
actual MSR load will be rejected by intel_is_valid_msr()).

Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220722224409.1336532-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/vmx/pmu_intel.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index ea5a7056fdfd..e73378b6f10c 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -335,6 +335,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
pmu->version = 0;
pmu->reserved_bits = 0xffffffff00200000ull;
pmu->raw_event_mask = X86_RAW_EVENT_MASK;
+ pmu->global_ctrl_mask = ~0ull;
+ pmu->global_ovf_ctrl_mask = ~0ull;
pmu->fixed_ctr_ctrl_mask = ~0ull;

entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
--
2.35.1