Index: usr.sbin/bhyve/bhyverun.h
===================================================================
--- usr.sbin/bhyve/bhyverun.h
+++ usr.sbin/bhyve/bhyverun.h
@@ -37,7 +37,6 @@
 struct vmctx;
 extern int guest_ncpus;
 extern uint16_t cores, sockets, threads;
-extern char *guest_uuid_str;
 extern const char *vmname;
 
 void *paddr_guest2host(struct vmctx *ctx, uintptr_t addr, size_t len);
Index: usr.sbin/bhyve/bhyverun.c
===================================================================
--- usr.sbin/bhyve/bhyverun.c
+++ usr.sbin/bhyve/bhyverun.c
@@ -69,6 +69,7 @@
 #include <sysexits.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <uuid.h>
 #ifdef BHYVE_SNAPSHOT
 #include <ucl.h>
 #include <unistd.h>
@@ -188,7 +189,7 @@
 int guest_ncpus;
 uint16_t cores, maxcpus, sockets, threads;
 
-char *guest_uuid_str;
+uuid_t guest_uuid;
 
 int raw_stdio = 0;
 
@@ -1106,6 +1107,8 @@
 	rtc_localtime = 1;
 	memflags = 0;
 
+	uuid_create_nil(guest_uuid, NULL);
+
 #ifdef BHYVE_SNAPSHOT
 	optstr = "aehuwxACDHIPSWYp:G:c:s:m:l:U:r:";
 #else
@@ -1196,7 +1199,10 @@
 			rtc_localtime = 0;
 			break;
 		case 'U':
-			guest_uuid_str = optarg;
+			uuid_from_string(optarg, &guest_uuid, &error);
+			if (error != uuid_s_ok) {
+				errx(EX_USAGE, "invalid UUID '%s'", optarg);
+			}
 			break;
 		case 'w':
 			strictmsr = 0;
Index: usr.sbin/bhyve/smbiostbl.c
===================================================================
--- usr.sbin/bhyve/smbiostbl.c
+++ usr.sbin/bhyve/smbiostbl.c
@@ -544,6 +544,8 @@
 static uint64_t guest_lomem, guest_himem;
 static uint16_t type16_handle;
 
+extern uuid_t guest_uuid;
+
 static int
 smbios_generic_initializer(struct smbios_structure *template_entry,
     const char **template_strings, char *curaddr, char **endaddr,
@@ -593,15 +595,8 @@
 	    curaddr, endaddr, n, size);
 	type1 = (struct smbios_table_type1 *)curaddr;
 
-	if (guest_uuid_str != NULL) {
-		uuid_t		uuid;
-		uint32_t	status;
-
-		uuid_from_string(guest_uuid_str, &uuid, &status);
-		if (status != uuid_s_ok)
-			return (-1);
-
-		uuid_enc_le(&type1->uuid, &uuid);
+	if (! uuid_is_nil(&guest_uuid, NULL)) {
+		uuid_enc_le(&type1->uuid, &guest_uuid);
 	} else {
 		MD5_CTX		mdctx;
 		u_char		digest[16];