From: Jan Klemkow <jan@openbsd.org>
Subject: vmd(8): Fix no kernel or disk error
To: tech@openbsd.org
Date: Sat, 19 Sep 2026 15:53:40 +0200

Hi,

If you try to start vmd(8) with the follwiing vm.conf:

vm "vm1" {
	disable
	boot "/bsd.rd"
}

you will run into the "no kernel or disk/cdrom specified" error.
If your start an anonymous vm via

# vmctl start -b /bsd.rd vm2

It works fine.

The configuration parser sets vmc->vmc_kernel to -1 and the flag
VMOP_CREATE_KERNEL.  The file is opens after vm_register().  In case of
"vmctl start -b" the file is already opened before vm_register().

But, the flag VMOP_CREATE_KERNEL was set in both cases before vm_register().
Thus, we should check for the flag and not for the filedescriptor in this case.
While here fix a wrong indentation, too.

ok?

bye,
Jan

diff --git a/usr.sbin/vmd/vmd.c b/usr.sbin/vmd/vmd.c
index b4741dc74fc..cb9925496aa 100644
--- a/usr.sbin/vmd/vmd.c
+++ b/usr.sbin/vmd/vmd.c
@@ -1212,8 +1212,8 @@ vm_register(struct privsep *ps, struct vmop_create_params *vmc,
 	} else if (vmc->vmc_nnics > VM_MAX_NICS_PER_VM) {
 		log_warnx("invalid number of interfaces");
 		goto fail;
-	} else if (vmc->vmc_kernel == -1 && vmc->vmc_ndisks == 0
-	    && strlen(vmc->vmc_cdrom) == 0) {
+	} else if ((vmc->vmc_flags & VMOP_CREATE_KERNEL) == 0 &&
+	    vmc->vmc_ndisks == 0 && strlen(vmc->vmc_cdrom) == 0) {
 		log_warnx("no kernel or disk/cdrom specified");
 		goto fail;
 	} else if (strlen(vmc->vmc_name) == 0) {
@@ -1416,7 +1416,7 @@ vm_instance(struct privsep *ps, struct vmd_vm **vm_parent,
 
 	/* kernel */
 	if (vmc->vmc_kernel > -1 || ((*vm_parent)->vm_kernel_path != NULL &&
-		strnlen((*vm_parent)->vm_kernel_path, PATH_MAX) < PATH_MAX)) {
+	    strnlen((*vm_parent)->vm_kernel_path, PATH_MAX) < PATH_MAX)) {
 		if (vm_checkinsflag(vmc_parent, VMOP_CREATE_KERNEL, uid) != 0) {
 			log_warnx("vm \"%s\" no permission to set boot image",
 			    name);