diff --git a/sys/amd64/vmm/amd/svm.c b/sys/amd64/vmm/amd/svm.c
--- a/sys/amd64/vmm/amd/svm.c
+++ b/sys/amd64/vmm/amd/svm.c
@@ -727,6 +727,55 @@
 	return (val);
 }
 
+static int
+decode_segment(struct svm_vcpu *svcpu, int *segment)
+{
+	struct vm_guest_paging *paging;
+	struct vie vie;
+	struct vm_exit *vme;
+	uint64_t cs_base;
+	int err;
+	int fault;
+
+	vme = vm_exitinfo(svcpu->vcpu);
+	paging = &vme->u.inst_emul.paging;
+	cs_base = vme->u.inst_emul.cs_base;
+
+	err = vmm_fetch_instruction(svcpu->vcpu, paging, vme->rip + cs_base,
+	    VIE_INST_SIZE, &vie, &fault);
+	if (err || fault)
+		return (err);
+
+	/*
+	 * Convert the segment override prefix to a 16-bit register number.
+	 */
+	switch (vie.inst[0]) {
+	case 0x26:
+		*segment = 0;
+		break;
+	case 0x2E:
+		*segment = 1;
+		break;
+	case 0x36:
+		*segment = 2;
+		break;
+	case 0x3E:
+		*segment = 3;
+		break;
+	case 0x64:
+		*segment = 4;
+		break;
+	case 0x65:
+		*segment = 5;
+		break;
+	default:
+		err = -1;
+		break;
+	}
+
+	return (err);
+}
+
 static void
 svm_inout_str_seginfo(struct svm_vcpu *vcpu, int64_t info1, int in,
     struct vm_inout_str *vis)
@@ -736,8 +785,22 @@
 	if (in) {
 		vis->seg_name = VM_REG_GUEST_ES;
 	} else {
-		/* The segment field has standard encoding */
-		s = (info1 >> 10) & 0x7;
+		/*
+		 * The effective segment number in EXITINFO1[12:10] is populated
+		 * only if the processor has the DecodeAssist capability.
+		 *
+		 * XXX this is not specified explicitly in APMv2 but can be
+		 * verified empirically.
+		 */
+		if (!decode_assist()) {
+			error = decode_segment(vcpu, &s);
+			if (error)
+				panic("%s: decode_segment error %d, error",
+				    __func__, error);
+		} else {
+			/* The segment field has standard encoding */
+			s = (info1 >> 10) & 0x7;
+		}
 		vis->seg_name = vm_segment_name(s);
 	}
 
@@ -798,16 +861,6 @@
 	info1 = ctrl->exitinfo1;
 	inout_string = info1 & BIT(2) ? 1 : 0;
 
-	/*
-	 * The effective segment number in EXITINFO1[12:10] is populated
-	 * only if the processor has the DecodeAssist capability.
-	 *
-	 * XXX this is not specified explicitly in APMv2 but can be verified
-	 * empirically.
-	 */
-	if (inout_string && !decode_assist())
-		return (UNHANDLED);
-
 	vmexit->exitcode 	= VM_EXITCODE_INOUT;
 	vmexit->u.inout.in 	= (info1 & BIT(0)) ? 1 : 0;
 	vmexit->u.inout.string 	= inout_string;