KVM: x86: Protect MSR-based index computations in pmu.h from Spectre-v1/L1TF attacks

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / arch / x86 / kvm / pmu.h

diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index f96e1f9..fbf3d25 100644 (file)
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -1,6 +1,8 @@
 #ifndef __KVM_X86_PMU_H
 #define __KVM_X86_PMU_H
 
+#include <linux/nospec.h>
+
 #define vcpu_to_pmu(vcpu) (&(vcpu)->arch.pmu)
 #define pmu_to_vcpu(pmu)  (container_of((pmu), struct kvm_vcpu, arch.pmu))
 #define pmc_to_pmu(pmc)   (&(pmc)->vcpu->arch.pmu)
@@ -80,8 +82,12 @@ static inline bool pmc_is_enabled(struct kvm_pmc *pmc)
 static inline struct kvm_pmc *get_gp_pmc(struct kvm_pmu *pmu, u32 msr,
                                         u32 base)
 {
-       if (msr >= base && msr < base + pmu->nr_arch_gp_counters)
-               return &pmu->gp_counters[msr - base];
+       if (msr >= base && msr < base + pmu->nr_arch_gp_counters) {
+               u32 index = array_index_nospec(msr - base,
+                                              pmu->nr_arch_gp_counters);
+
+               return &pmu->gp_counters[index];
+       }
 
        return NULL;
 }
@@ -91,8 +97,12 @@ static inline struct kvm_pmc *get_fixed_pmc(struct kvm_pmu *pmu, u32 msr)
 {
        int base = MSR_CORE_PERF_FIXED_CTR0;
 
-       if (msr >= base && msr < base + pmu->nr_arch_fixed_counters)
-               return &pmu->fixed_counters[msr - base];
+       if (msr >= base && msr < base + pmu->nr_arch_fixed_counters) {
+               u32 index = array_index_nospec(msr - base,
+                                              pmu->nr_arch_fixed_counters);
+
+               return &pmu->fixed_counters[index];
+       }
 
        return NULL;
 }