linux-kernel - [PATCH v6 01/20] KVM: x86/pmu: Don't allow exposing unsupported architectural events

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Message-ID: <20231104000239.367005-2-seanjc@google.com>
Date:   Fri,  3 Nov 2023 17:02:19 -0700
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,
        Kan Liang <kan.liang@...ux.intel.com>,
        Dapeng Mi <dapeng1.mi@...ux.intel.com>,
        Jinrong Liang <cloudliang@...cent.com>,
        Like Xu <likexu@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Aaron Lewis <aaronlewis@...gle.com>
Subject: [PATCH v6 01/20] KVM: x86/pmu: Don't allow exposing unsupported
 architectural events

Hide architectural events that unsupported according to guest CPUID *or*
hardware, i.e. don't let userspace advertise and potentially program
unsupported architectural events.

Note, KVM already limits the length of the reverse polarity field, only
the mask itself is missing.

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, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 820d3e1f6b4f..1b13a472e3f2 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -533,7 +533,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1;
 	eax.split.mask_length = min_t(int, eax.split.mask_length,
 				      kvm_pmu_cap.events_mask_len);
-	pmu->available_event_types = ~entry->ebx &
+	pmu->available_event_types = ~(entry->ebx | kvm_pmu_cap.events_mask) &
 					((1ull << eax.split.mask_length) - 1);
 
 	if (pmu->version == 1) {
-- 
2.42.0.869.gea05f2083d-goog