1 files changed, 40 insertions, 16 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 5abaa5b2f624..d84f6a7c2bc5 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2745,6 +2745,30 @@ static int cr0_write_interception(struct vcpu_svm *svm)
         return r;
 }
 
+static int dr_interception(struct vcpu_svm *svm)
+{
+        int reg, dr;
+        unsigned long val;
+        int err;
+
+        if (!boot_cpu_has(X86_FEATURE_DECODEASSISTS))
+                return emulate_on_interception(svm);
+
+        reg = svm->vmcb->control.exit_info_1 & SVM_EXITINFO_REG_MASK;
+        dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
+
+        if (dr >= 16) { /* mov to DRn */
+                val = kvm_register_read(&svm->vcpu, reg);
+                kvm_set_dr(&svm->vcpu, dr - 16, val);
+        } else {
+                err = kvm_get_dr(&svm->vcpu, dr, &val);
+                if (!err)
+                        kvm_register_write(&svm->vcpu, reg, val);
+        }
+
+        return 1;
+}
+
 static int cr8_write_interception(struct vcpu_svm *svm)
 {
         struct kvm_run *kvm_run = svm->vcpu.run;
@@ -3010,22 +3034,22 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm) = {
         [SVM_EXIT_WRITE_CR3]                    = cr_interception,
         [SVM_EXIT_WRITE_CR4]                    = cr_interception,
         [SVM_EXIT_WRITE_CR8]                    = cr8_write_interception,
-        [SVM_EXIT_READ_DR0]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR1]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR2]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR3]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR4]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR5]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR6]                     = emulate_on_interception,
-        [SVM_EXIT_READ_DR7]                     = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR0]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR1]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR2]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR3]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR4]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR5]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR6]                    = emulate_on_interception,
-        [SVM_EXIT_WRITE_DR7]                    = emulate_on_interception,
+        [SVM_EXIT_READ_DR0]                     = dr_interception,
+        [SVM_EXIT_READ_DR1]                     = dr_interception,
+        [SVM_EXIT_READ_DR2]                     = dr_interception,
+        [SVM_EXIT_READ_DR3]                     = dr_interception,
+        [SVM_EXIT_READ_DR4]                     = dr_interception,
+        [SVM_EXIT_READ_DR5]                     = dr_interception,
+        [SVM_EXIT_READ_DR6]                     = dr_interception,
+        [SVM_EXIT_READ_DR7]                     = dr_interception,
+        [SVM_EXIT_WRITE_DR0]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR1]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR2]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR3]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR4]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR5]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR6]                    = dr_interception,
+        [SVM_EXIT_WRITE_DR7]                    = dr_interception,
         [SVM_EXIT_EXCP_BASE + DB_VECTOR]        = db_interception,
         [SVM_EXIT_EXCP_BASE + BP_VECTOR]        = bp_interception,
         [SVM_EXIT_EXCP_BASE + UD_VECTOR]        = ud_interception,