[SeaBIOS] trying to boot off vhost-user-fs-pci device?

[Michael Tokarev]

Hi!

While debugging an unrelated issue, I come to an interesting effect.

When I run qemu with two devices, one vhost-user-fs-pci and another,
say, virtio-blk, - both these devices have bootindex property.  If
I specify virtio-blk first and vhost-user-fs-pci second, everything
works as expected and seabios boots the OS out of virtio-blk device.
But if I specify vhost-user-fs-pci first, seabios will try to boot
off virtiofs one, which isn't even a block device, and for which
seabios does not have any driver.  And in this case the boot just
fails:

Booting from Hard Disk..
  Boot failed: could not read the boot disk

next it tries pxe boot, cdrom, and fails.

Does it make sense to try to boot off unsupported devices?

Thanks,

/mjt