[PATCH 06/10] KVM: x86: nSVM: Add validity check for VMCB12 g_pat

[Jim Mattson]

When nested paging is enabled for VMCB12, an invalid g_pat causes an
immediate #VMEXIT with exit code VMEXIT_INVALID, as specified in the
APM, volume 2: "Nested Paging and VMRUN/#VMEXIT."

Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler")
Signed-off-by: Jim Mattson <jmatt...@google.com>
---
 arch/x86/kvm/svm/nested.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index ad9272aae908..501102625f69 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -369,7 +369,8 @@ static bool __nested_vmcb_check_controls(struct kvm_vcpu 
*vcpu,
 
 /* Common checks that apply to both L1 and L2 state.  */
 static bool __nested_vmcb_check_save(struct kvm_vcpu *vcpu,
-                                    struct vmcb_save_area_cached *save)
+                                    struct vmcb_save_area_cached *save,
+                                    struct vmcb_ctrl_area_cached *control)
 {
        if (CC(!(save->efer & EFER_SVME)))
                return false;
@@ -400,6 +401,10 @@ static bool __nested_vmcb_check_save(struct kvm_vcpu *vcpu,
        if (CC(!kvm_valid_efer(vcpu, save->efer)))
                return false;
 
+       if (CC((control->nested_ctl & SVM_NESTED_CTL_NP_ENABLE) &&
+              npt_enabled && !kvm_pat_valid(save->g_pat)))
+               return false;
+
        return true;
 }
 
@@ -407,8 +412,9 @@ static bool nested_vmcb_check_save(struct kvm_vcpu *vcpu)
 {
        struct vcpu_svm *svm = to_svm(vcpu);
        struct vmcb_save_area_cached *save = &svm->nested.save;
+       struct vmcb_ctrl_area_cached *ctl = &svm->nested.ctl;
 
-       return __nested_vmcb_check_save(vcpu, save);
+       return __nested_vmcb_check_save(vcpu, save, ctl);
 }
 
 static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu)
@@ -1911,7 +1917,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
        if (!(save->cr0 & X86_CR0_PG) ||
            !(save->cr0 & X86_CR0_PE) ||
            (save->rflags & X86_EFLAGS_VM) ||
-           !__nested_vmcb_check_save(vcpu, &save_cached))
+           !__nested_vmcb_check_save(vcpu, &save_cached, &ctl_cached))
                goto out_free;
 
 
-- 
2.52.0.457.g6b5491de43-goog