KVM: MMU: Track NX state in struct kvm_mmu

With Nested Paging emulation the NX state between the two
MMU contexts may differ. To make sure that always the right
fault error code is recorded this patch moves the NX state
into struct kvm_mmu so that the code can distinguish between
L1 and L2 NX state.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index bd59b48..b43686a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -259,6 +259,8 @@
 	u64 *lm_root;
 	u64 rsvd_bits_mask[2][4];
 
+	bool nx;
+
 	u64 pdptrs[4]; /* pae */
 };
 
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index dd76765..95cbeed 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2634,6 +2634,7 @@
 	context->shadow_root_level = PT32E_ROOT_LEVEL;
 	context->root_hpa = INVALID_PAGE;
 	context->direct_map = true;
+	context->nx = false;
 	return 0;
 }
 
@@ -2687,7 +2688,7 @@
 	int maxphyaddr = cpuid_maxphyaddr(vcpu);
 	u64 exb_bit_rsvd = 0;
 
-	if (!is_nx(vcpu))
+	if (!context->nx)
 		exb_bit_rsvd = rsvd_bits(63, 63);
 	switch (level) {
 	case PT32_ROOT_LEVEL:
@@ -2746,6 +2747,8 @@
 					struct kvm_mmu *context,
 					int level)
 {
+	context->nx = is_nx(vcpu);
+
 	reset_rsvds_bits_mask(vcpu, context, level);
 
 	ASSERT(is_pae(vcpu));
@@ -2772,6 +2775,8 @@
 static int paging32_init_context(struct kvm_vcpu *vcpu,
 				 struct kvm_mmu *context)
 {
+	context->nx = false;
+
 	reset_rsvds_bits_mask(vcpu, context, PT32_ROOT_LEVEL);
 
 	context->new_cr3 = paging_new_cr3;
@@ -2810,19 +2815,24 @@
 	context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
 	context->get_cr3 = get_cr3;
 	context->inject_page_fault = kvm_inject_page_fault;
+	context->nx = is_nx(vcpu);
 
 	if (!is_paging(vcpu)) {
+		context->nx = false;
 		context->gva_to_gpa = nonpaging_gva_to_gpa;
 		context->root_level = 0;
 	} else if (is_long_mode(vcpu)) {
+		context->nx = is_nx(vcpu);
 		reset_rsvds_bits_mask(vcpu, context, PT64_ROOT_LEVEL);
 		context->gva_to_gpa = paging64_gva_to_gpa;
 		context->root_level = PT64_ROOT_LEVEL;
 	} else if (is_pae(vcpu)) {
+		context->nx = is_nx(vcpu);
 		reset_rsvds_bits_mask(vcpu, context, PT32E_ROOT_LEVEL);
 		context->gva_to_gpa = paging64_gva_to_gpa;
 		context->root_level = PT32E_ROOT_LEVEL;
 	} else {
+		context->nx = false;
 		reset_rsvds_bits_mask(vcpu, context, PT32_ROOT_LEVEL);
 		context->gva_to_gpa = paging32_gva_to_gpa;
 		context->root_level = PT32_ROOT_LEVEL;
@@ -2878,17 +2888,21 @@
 	 * functions between mmu and nested_mmu are swapped.
 	 */
 	if (!is_paging(vcpu)) {
+		g_context->nx = false;
 		g_context->root_level = 0;
 		g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
 	} else if (is_long_mode(vcpu)) {
+		g_context->nx = is_nx(vcpu);
 		reset_rsvds_bits_mask(vcpu, g_context, PT64_ROOT_LEVEL);
 		g_context->root_level = PT64_ROOT_LEVEL;
 		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
 	} else if (is_pae(vcpu)) {
+		g_context->nx = is_nx(vcpu);
 		reset_rsvds_bits_mask(vcpu, g_context, PT32E_ROOT_LEVEL);
 		g_context->root_level = PT32E_ROOT_LEVEL;
 		g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
 	} else {
+		g_context->nx = false;
 		reset_rsvds_bits_mask(vcpu, g_context, PT32_ROOT_LEVEL);
 		g_context->root_level = PT32_ROOT_LEVEL;
 		g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index a28f09b..2bdd843 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -105,7 +105,7 @@
 
 	access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
 #if PTTYPE == 64
-	if (is_nx(vcpu))
+	if (vcpu->arch.mmu.nx)
 		access &= ~(gpte >> PT64_NX_SHIFT);
 #endif
 	return access;
@@ -272,7 +272,7 @@
 		walker->error_code |= PFERR_WRITE_MASK;
 	if (user_fault)
 		walker->error_code |= PFERR_USER_MASK;
-	if (fetch_fault && is_nx(vcpu))
+	if (fetch_fault && mmu->nx)
 		walker->error_code |= PFERR_FETCH_MASK;
 	if (rsvd_fault)
 		walker->error_code |= PFERR_RSVD_MASK;