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

#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)

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;

}

{

	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;

}