KVM: X86: Introduce pointer to mmu context used for gva_to_gpa

This patch introduces the walk_mmu pointer which points to
the mmu-context currently used for gva_to_gpa translations.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -286,8 +286,21 @@ struct kvm_vcpu_arch {
 	u64 ia32_misc_enable_msr;
 	bool tpr_access_reporting;
 
+	/*
+	 * Paging state of the vcpu
+	 *
+	 * If the vcpu runs in guest mode with two level paging this still saves
+	 * the paging mode of the l1 guest. This context is always used to
+	 * handle faults.
+	 */
 	struct kvm_mmu mmu;
 
+	/*
+	 * Pointer to the mmu context currently used for
+	 * gva_to_gpa translations.
+	 */
+	struct kvm_mmu *walk_mmu;
+
 	/*
 	 * This struct is filled with the necessary information to propagate a
 	 * page fault into the guest

arch/x86/kvm/mmu.c

@@ -2708,7 +2708,7 @@ static int paging32E_init_context(struct kvm_vcpu *vcpu,
 
 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 {
-	struct kvm_mmu *context = &vcpu->arch.mmu;
+	struct kvm_mmu *context = vcpu->arch.walk_mmu;
 
 	context->new_cr3 = nonpaging_new_cr3;
 	context->page_fault = tdp_page_fault;
@@ -2767,11 +2767,11 @@ EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
 
 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
 {
-	int r = kvm_init_shadow_mmu(vcpu, &vcpu->arch.mmu);
+	int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
 
-	vcpu->arch.mmu.set_cr3           = kvm_x86_ops->set_cr3;
-	vcpu->arch.mmu.get_cr3           = get_cr3;
-	vcpu->arch.mmu.inject_page_fault = kvm_inject_page_fault;
+	vcpu->arch.walk_mmu->set_cr3           = kvm_x86_ops->set_cr3;
+	vcpu->arch.walk_mmu->get_cr3           = get_cr3;
+	vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
 
 	return r;
 }

arch/x86/kvm/x86.c

@@ -3456,27 +3456,27 @@ static gpa_t translate_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access)
 gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
 {
 	u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
-	return vcpu->arch.mmu.gva_to_gpa(vcpu, gva, access, error);
+	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, error);
 }
 
  gpa_t kvm_mmu_gva_to_gpa_fetch(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
 {
 	u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
 	access |= PFERR_FETCH_MASK;
-	return vcpu->arch.mmu.gva_to_gpa(vcpu, gva, access, error);
+	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, error);
 }
 
 gpa_t kvm_mmu_gva_to_gpa_write(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
 {
 	u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
 	access |= PFERR_WRITE_MASK;
-	return vcpu->arch.mmu.gva_to_gpa(vcpu, gva, access, error);
+	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, error);
 }
 
 /* uses this to access any guest's mapped memory without checking CPL */
 gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
 {
-	return vcpu->arch.mmu.gva_to_gpa(vcpu, gva, 0, error);
+	return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, 0, error);
 }
 
 static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
@@ -3487,7 +3487,8 @@ static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
 	int r = X86EMUL_CONTINUE;
 
 	while (bytes) {
-		gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr, access, error);
+		gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr, access,
+							    error);
 		unsigned offset = addr & (PAGE_SIZE-1);
 		unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset);
 		int ret;
@@ -3542,8 +3543,9 @@ static int kvm_write_guest_virt_system(gva_t addr, void *val,
 	int r = X86EMUL_CONTINUE;
 
 	while (bytes) {
-		gpa_t gpa =  vcpu->arch.mmu.gva_to_gpa(vcpu, addr,
-						       PFERR_WRITE_MASK, error);
+		gpa_t gpa =  vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr,
+							     PFERR_WRITE_MASK,
+							     error);
 		unsigned offset = addr & (PAGE_SIZE-1);
 		unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
 		int ret;
@@ -5663,6 +5665,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	kvm = vcpu->kvm;
 
 	vcpu->arch.emulate_ctxt.ops = &emulate_ops;
+	vcpu->arch.walk_mmu = &vcpu->arch.mmu;
 	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
 	vcpu->arch.mmu.translate_gpa = translate_gpa;
 	if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))