[SeaBIOS] Marvell 88SE9230 passthrough in KVM takes long time to boot

[Gerd Hoffmann]

On Sun, Jul 29, 2018 at 01:49:10PM +0200, Konrad Eisele wrote:
> I'm passing through a Marvell 88SE9230 card to a KVM guest under
> Ubuntu 18.04. The card is a Sata controller with 4 ports.
> The option rom of the Marvell 88SE9230 card shows on a normal boot a
> bios screen. When pressing CTRL-m quick enough, you  can interrupt the
> bootprocess and enter a menue wherer you can define raid
> arrays.
> 
> When booting seabios inside KVM the bootprocess is very slow.
> There is a 1 min holdtime where the cpu is about 30%. The screen is
> black with only the seabios version string shown. I suspect that
> the passed-through Marvell 88SE9230 cards option roms causes this
> behaviour.
> Maybe the scanning for option rom cause the slow bootprocess?
> 
> In the seabios boot case no bios menue is shown, after
> around 1 min the boot continues.
> 
> Is it possible to disable the options rom processing? Is there some
> documentation about this (How can I configure it for Ubuntu) ?

Set the romfile option to the empty string (for vfio-pci, on the qemu
command line) should do that (qemu will not expose the rom to the guest
then).

cheers,
  Gerd