[RFC PATCH 3/6] KVM: x86: nSVM: Copy current vmcb02 g_pat to vmcb12 g_pat on #VMEXIT

Jim Mattson posted 6 patches 1 month, 1 week ago
[RFC PATCH 3/6] KVM: x86: nSVM: Copy current vmcb02 g_pat to vmcb12 g_pat on #VMEXIT
Posted by Jim Mattson 1 month, 1 week ago
According to the APM volume 3 pseudo-code for "VMRUN," when nested
paging is enabled in the VMCB, the guest PAT register is copied into
the g_pat field of the VMCB on #VMEXIT.

In KVM, the guest PAT register is the g_pat field of vmcb02. When
nested paging is enabled in vmcb12, copy the g_pat field of the vmcb02
to the g_pat field of the vmcb12 in nested_svm_vmexit().

Fixes: 15038e147247 ("KVM: SVM: obey guest PAT")
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/svm/nested.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index c68511948501..51a89d6aa29f 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1126,6 +1126,9 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	vmcb12->save.dr6    = svm->vcpu.arch.dr6;
 	vmcb12->save.cpl    = vmcb02->save.cpl;
 
+	if (nested_npt_enabled(svm))
+		vmcb12->save.g_pat = vmcb02->save.g_pat;
+
 	if (guest_cpu_cap_has(vcpu, X86_FEATURE_SHSTK)) {
 		vmcb12->save.s_cet	= vmcb02->save.s_cet;
 		vmcb12->save.isst_addr	= vmcb02->save.isst_addr;
-- 
2.51.2.1041.gc1ab5b90ca-goog