Index: stand/userboot/userboot.h
===================================================================
--- stand/userboot/userboot.h
+++ stand/userboot/userboot.h
@@ -41,6 +41,14 @@
  */
 #define	USERBOOT_VERSION_4      4
 
+/*
+ * Version 5 adds callbacks to set up long mode and set
+ * unrestricted guest capabilities. The callback structure
+ * backward compatible (new callbacks have been added at
+ * the tail end).
+ */
+#define	USERBOOT_VERSION_5      5
+
 /*
  * Exit codes from the loader
  */
@@ -210,4 +218,17 @@
 	int	(*vm_set_register)(void *arg, int vcpu, int reg, uint64_t val);
 	int	(*vm_set_desc)(void *arg, int vcpu, int reg, uint64_t base,
 	    u_int limit, u_int access);
+
+	/*
+	 * Version 5 additions.
+	 *
+	 * vm_get_unrestricted_guest checks support for the UNRESTRICTED_GUEST
+	 * capability and if supported, sets 'retval'. If unsupported, an error
+	 * code is returned.
+	 *
+	 * vm_set_unrestricted_guest sets the UNRESTRICTED_GUEST capability if
+	 * supported, and returns an error code otherwise.
+	 */
+	int	(*vm_get_unrestricted_guest)(void* arg, int vcpu, int *retval);
+	int	(*vm_set_unrestricted_guest)(void* arg, int vcpu, int val);
 };
Index: usr.sbin/bhyveload/bhyveload.c
===================================================================
--- usr.sbin/bhyveload/bhyveload.c
+++ usr.sbin/bhyveload/bhyveload.c
@@ -560,6 +560,24 @@
 	return (vm_set_desc(ctx, vcpu, reg, base, limit, access));
 }
 
+static int
+cb_vm_get_unrestricted_guest(void* arg, int vcpu, int *retval)
+{
+	return (vm_get_capability(ctx, vcpu,
+			VM_CAP_UNRESTRICTED_GUEST, retval));
+}
+
+static int
+cb_vm_set_unrestricted_guest(void* arg, int vcpu, int val)
+{
+	int error, tmp;
+	if ((error = cb_vm_get_unrestricted_guest(arg, vcpu, &tmp)))
+		return error;
+
+	return (vm_set_capability(ctx, vcpu,
+			VM_CAP_UNRESTRICTED_GUEST, val));
+}
+
 static struct loader_callbacks cb = {
 	.getc = cb_getc,
 	.putc = cb_putc,
@@ -593,6 +611,10 @@
 	/* Version 4 additions */
 	.vm_set_register = cb_vm_set_register,
 	.vm_set_desc = cb_vm_set_desc,
+
+	/* Version 5 additions */
+	.vm_set_unrestricted_guest = cb_vm_set_unrestricted_guest,
+	.vm_get_unrestricted_guest = cb_vm_get_unrestricted_guest,
 };
 
 static int