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>

2 files changed, 32 insertions, 1 deletions

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 38638cd2fa4c..b26a38d85356 100644
--- a/arch/x86/include/asm/svm.h
+++ b/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;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index cac761c6d1dc..b4aac5c7ad87 100644
--- a/arch/x86/kvm/svm.c
+++ b/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;