[PATCH 3.16 088/136] KVM: vmx: Inject #GP on invalid PAT CR

[Ben Hutchings]

3.16.54-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Nadav Amit <na...@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 <na...@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Ben Hutchings <b...@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
@@ -2599,6 +2599,8 @@ 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
@@ -1742,7 +1742,7 @@ 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;
 
@@ -1768,12 +1768,13 @@ 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
@@ -132,6 +132,8 @@ 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);
+
 #define KVM_SUPPORTED_XCR0     (XSTATE_FP | XSTATE_SSE | XSTATE_YMM \
                                | XSTATE_BNDREGS | XSTATE_BNDCSR)
 extern u64 host_xcr0;