[PATCH v5 01/13] KVM: x86/pmu: Don't allow exposing unsupported architectural events

Sean Christopherson
2023-10-24T00:26:48Z

Hide architectural events that are 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@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.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) {
--
2.42.0.758.gaed0368e0e-goog