From: Marios Pomonis <pomonis@xxxxxxxxxx>
[ Upstream commit 66061740f1a487f4ed54fde75e724709f805da53 ]
This fixes Spectre-v1/L1TF vulnerabilities in intel_find_fixed_event()
and intel_rdpmc_ecx_to_pmc().
kvm_rdpmc() (ancestor of intel_find_fixed_event()) and
reprogram_fixed_counter() (ancestor of intel_rdpmc_ecx_to_pmc()) are
exported symbols so KVM should treat them conservatively from a security
perspective.
Fixes: 25462f7f5295 ("KVM: x86/vPMU: Define kvm_pmu_ops to support vPMU function dispatch")
Signed-off-by: Nick Finco <nifi@xxxxxxxxxx>
Signed-off-by: Marios Pomonis <pomonis@xxxxxxxxxx>
Reviewed-by: Andrew Honig <ahonig@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/x86/kvm/pmu_intel.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/pmu_intel.c b/arch/x86/kvm/pmu_intel.c
index 2729131fe9bfc..84ae4dd261caf 100644
--- a/arch/x86/kvm/pmu_intel.c
+++ b/arch/x86/kvm/pmu_intel.c
@@ -87,10 +87,14 @@ static unsigned intel_find_arch_event(struct kvm_pmu *pmu,
static unsigned intel_find_fixed_event(int idx)
{
- if (idx >= ARRAY_SIZE(fixed_pmc_events))
+ u32 event;
+ size_t size = ARRAY_SIZE(fixed_pmc_events);
+
+ if (idx >= size)
return PERF_COUNT_HW_MAX;
- return intel_arch_events[fixed_pmc_events[idx]].event_type;
+ event = fixed_pmc_events[array_index_nospec(idx, size)];
+ return intel_arch_events[event].event_type;
}
/* check if a PMC is enabled by comparing it with globl_ctrl bits. */
@@ -131,15 +135,19 @@ static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu,
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
bool fixed = idx & (1u << 30);
struct kvm_pmc *counters;
+ unsigned int num_counters;
idx &= ~(3u << 30);
- if (!fixed && idx >= pmu->nr_arch_gp_counters)
- return NULL;
- if (fixed && idx >= pmu->nr_arch_fixed_counters)
+ if (fixed) {
+ counters = pmu->fixed_counters;
+ num_counters = pmu->nr_arch_fixed_counters;
+ } else {
+ counters = pmu->gp_counters;
+ num_counters = pmu->nr_arch_gp_counters;
+ }
+ if (idx >= num_counters)
return NULL;
- counters = fixed ? pmu->fixed_counters : pmu->gp_counters;
-
- return &counters[idx];
+ return &counters[array_index_nospec(idx, num_counters)];
}
static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
--
2.20.1
