KVM: SVM: Implement emulation of vm_cr msr

This patch implements the emulation of the vm_cr msr for
nested svm.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/include/asm/svm.h

@@ -115,6 +115,10 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
 #define SVM_IOIO_SIZE_MASK (7 << SVM_IOIO_SIZE_SHIFT)
 #define SVM_IOIO_ASIZE_MASK (7 << SVM_IOIO_ASIZE_SHIFT)
 
+#define SVM_VM_CR_VALID_MASK	0x001fULL
+#define SVM_VM_CR_SVM_LOCK_MASK 0x0008ULL
+#define SVM_VM_CR_SVM_DIS_MASK  0x0010ULL
+
 struct __attribute__ ((__packed__)) vmcb_seg {
 	u16 selector;
 	u16 attrib;

arch/x86/kvm/svm.c

@@ -71,6 +71,7 @@ struct kvm_vcpu;
 struct nested_state {
 	struct vmcb *hsave;
 	u64 hsave_msr;
+	u64 vm_cr_msr;
 	u64 vmcb;
 
 	/* These are the merged vectors */
@@ -2280,7 +2281,7 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
 		*data = svm->nested.hsave_msr;
 		break;
 	case MSR_VM_CR:
-		*data = 0;
+		*data = svm->nested.vm_cr_msr;
 		break;
 	case MSR_IA32_UCODE_REV:
 		*data = 0x01000065;
@@ -2310,6 +2311,31 @@ static int rdmsr_interception(struct vcpu_svm *svm)
 	return 1;
 }
 
+static int svm_set_vm_cr(struct kvm_vcpu *vcpu, u64 data)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	int svm_dis, chg_mask;
+
+	if (data & ~SVM_VM_CR_VALID_MASK)
+		return 1;
+
+	chg_mask = SVM_VM_CR_VALID_MASK;
+
+	if (svm->nested.vm_cr_msr & SVM_VM_CR_SVM_DIS_MASK)
+		chg_mask &= ~(SVM_VM_CR_SVM_LOCK_MASK | SVM_VM_CR_SVM_DIS_MASK);
+
+	svm->nested.vm_cr_msr &= ~chg_mask;
+	svm->nested.vm_cr_msr |= (data & chg_mask);
+
+	svm_dis = svm->nested.vm_cr_msr & SVM_VM_CR_SVM_DIS_MASK;
+
+	/* check for svm_disable while efer.svme is set */
+	if (svm_dis && (vcpu->arch.efer & EFER_SVME))
+		return 1;
+
+	return 0;
+}
+
 static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -2376,6 +2402,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 		svm->nested.hsave_msr = data;
 		break;
 	case MSR_VM_CR:
+		return svm_set_vm_cr(vcpu, data);
 	case MSR_VM_IGNNE:
 		pr_unimpl(vcpu, "unimplemented wrmsr: 0x%x data 0x%llx\n", ecx, data);
 		break;