linux-kernel - [PATCH 2/5] KVM: VMX: Mark all PERF_GLOBAL_(OVF)

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Message-Id: <20220722224409.1336532-3-seanjc@google.com>
Date:   Fri, 22 Jul 2022 22:44:06 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/5] KVM: VMX: Mark all PERF_GLOBAL_(OVF)_CTRL bits reserved
 if there's no vPMU

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@...r.kernel.org
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 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 4bc098fbec31..6e355c5d2f40 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -527,6 +527,8 @@ 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;
 	pmu->pebs_enable_mask = ~0ull;
 	pmu->pebs_data_cfg_mask = ~0ull;
-- 
2.37.1.359.gd136c6c3e2-goog