diff options
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index e073e3008b16..fd2bf3262e11 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -824,12 +824,30 @@ static int nested_vmx_check_apicv_controls(struct kvm_vcpu *vcpu, return 0; } +static u32 nested_vmx_max_atomic_switch_msrs(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + u64 vmx_misc = vmx_control_msr(vmx->nested.msrs.misc_low, + vmx->nested.msrs.misc_high); + + return (vmx_misc_max_msr(vmx_misc) + 1) * VMX_MISC_MSR_LIST_MULTIPLIER; +} + static int nested_vmx_check_msr_switch(struct kvm_vcpu *vcpu, u32 count, u64 addr) { if (count == 0) return 0; + /* + * Exceeding the limit results in architecturally _undefined_ behavior, + * i.e. KVM is allowed to do literally anything in response to a bad + * limit. Immediately generate a consistency check so that code that + * consumes the count doesn't need to worry about extreme edge cases. + */ + if (count > nested_vmx_max_atomic_switch_msrs(vcpu)) + return -EINVAL; + if (!kvm_vcpu_is_legal_aligned_gpa(vcpu, addr, 16) || !kvm_vcpu_is_legal_gpa(vcpu, (addr + count * sizeof(struct vmx_msr_entry) - 1))) return -EINVAL; @@ -940,15 +958,6 @@ static int nested_vmx_store_msr_check(struct kvm_vcpu *vcpu, return 0; } -static u32 nested_vmx_max_atomic_switch_msrs(struct kvm_vcpu *vcpu) -{ - struct vcpu_vmx *vmx = to_vmx(vcpu); - u64 vmx_misc = vmx_control_msr(vmx->nested.msrs.misc_low, - vmx->nested.msrs.misc_high); - - return (vmx_misc_max_msr(vmx_misc) + 1) * VMX_MISC_MSR_LIST_MULTIPLIER; -} - /* * Load guest's/host's msr at nested entry/exit. * return 0 for success, entry index for failure. @@ -965,7 +974,7 @@ static u32 nested_vmx_load_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count) u32 max_msr_list_size = nested_vmx_max_atomic_switch_msrs(vcpu); for (i = 0; i < count; i++) { - if (unlikely(i >= max_msr_list_size)) + if (WARN_ON_ONCE(i >= max_msr_list_size)) goto fail; if (kvm_vcpu_read_guest(vcpu, gpa + i * sizeof(e), @@ -1053,7 +1062,7 @@ static int nested_vmx_store_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count) u32 max_msr_list_size = nested_vmx_max_atomic_switch_msrs(vcpu); for (i = 0; i < count; i++) { - if (unlikely(i >= max_msr_list_size)) + if (WARN_ON_ONCE(i >= max_msr_list_size)) return -EINVAL; if (!read_and_check_msr_entry(vcpu, gpa, i, &e)) |