diff options
| -rw-r--r-- | arch/x86/kvm/mtrr.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c index cfeeaef9e419..b081e3ba186f 100644 --- a/arch/x86/kvm/mtrr.c +++ b/arch/x86/kvm/mtrr.c @@ -241,10 +241,25 @@ static int fixed_msr_to_range_index(u32 msr) return fixed_mtrr_seg_unit_range_index(seg, unit); } +static void var_mtrr_range(struct kvm_mtrr_range *range, u64 *start, u64 *end) +{ + u64 mask; + + *start = range->base & PAGE_MASK; + + mask = range->mask & PAGE_MASK; + mask |= ~0ULL << boot_cpu_data.x86_phys_bits; + + /* This cannot overflow because writing to the reserved bits of + * variable MTRRs causes a #GP. + */ + *end = (*start | ~mask) + 1; +} + static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr) { struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state; - gfn_t start, end, mask; + gfn_t start, end; int index; if (msr == MSR_IA32_CR_PAT || !tdp_enabled || @@ -264,11 +279,7 @@ static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr) } else { /* variable range MTRRs. */ index = (msr - 0x200) / 2; - start = mtrr_state->var_ranges[index].base & PAGE_MASK; - mask = mtrr_state->var_ranges[index].mask & PAGE_MASK; - mask |= ~0ULL << cpuid_maxphyaddr(vcpu); - - end = ((start & mask) | ~mask) + 1; + var_mtrr_range(&mtrr_state->var_ranges[index], &start, &end); } kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end)); |