[PATCH 3.2 46/79] KVM: vmx: Inject #GP on invalid PAT CR

Ben Hutchings
2018-02-11T04:20:06Z

From: Nadav Amit <namit@cs.technion.ac.il>

commit 4566654bb9be9e8864df417bb72ceee5136b6a6a upstream.

Guest which sets the PAT CR to invalid value should get a #GP. Currently, if
vmx supports loading PAT CR during entry, then the value is not checked. This
patch makes the required check in that case.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/x86/kvm/vmx.c | 2 ++
arch/x86/kvm/x86.c | 5 +++--
arch/x86/kvm/x86.h | 2 ++
3 files changed, 7 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2204,6 +2204,8 @@ static int vmx_set_msr(struct kvm_vcpu *
break;
case MSR_IA32_CR_PAT:
if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
+ if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
+ return 1;
vmcs_write64(GUEST_IA32_PAT, data);
vcpu->arch.pat = data;
break;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1274,7 +1274,7 @@ static bool valid_mtrr_type(unsigned t)
return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
}

-static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
+bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
int i;

@@ -1300,12 +1300,13 @@ static bool mtrr_valid(struct kvm_vcpu *
/* variable MTRRs */
return valid_mtrr_type(data & 0xff);
}
+EXPORT_SYMBOL_GPL(kvm_mtrr_valid);

static int set_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
u64 *p = (u64 *)&vcpu->arch.mtrr_state.fixed_ranges;

- if (!mtrr_valid(vcpu, msr, data))
+ if (!kvm_mtrr_valid(vcpu, msr, data))
return 1;

if (msr == MSR_MTRRdefType) {
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -135,6 +135,8 @@ int kvm_write_guest_virt_system(struct x
gva_t addr, void *val, unsigned int bytes,
struct x86_exception *exception);

+bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data);
+
extern unsigned int min_timer_period_us;

#endif