Previously, KVM didn't record the vmcb01 G_PAT (i.e. the IA32_PAT MSR) in the serialized nested state. It didn't have to, because it ignored the vmcb12 g_pat field entirely. L1 and L2 simply shared the same PAT.
To preserve legacy behavior, copy the current value of the IA32_PAT MSR to the location of the vmcb01 G_PAT in the serialized nested state. (On restore, KVM_SET_MSRS should be called before KVM_SET_NESTED_STATE, so the value of the shared IA32_PAT MSR should be available.)
Signed-off-by: Jim Mattson jmattson@google.com --- arch/x86/kvm/svm/nested.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index ed24e08d2d21..c751be470364 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1884,6 +1884,13 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW)) goto out_free;
+ /* + * If kvm_state doesn't have a valid saved L1 g_pat, use the + * PAT MSR instead. This preserves the legacy behavior. + */ + if (!(kvm_state->hdr.svm.flags & KVM_STATE_SVM_VALID_GPAT)) + save->g_pat = vcpu->arch.pat; + /* * Validate host state saved from before VMRUN (see * nested_svm_check_permissions).