Re: [PATCH] pci: make ROM memory resizable

[Vladimir Sementsov-Ogievskiy]

On 25.04.23 15:10, Gerd Hoffmann wrote:
> On Tue, Apr 25, 2023 at 03:26:50AM -0400, Michael S. Tsirkin wrote:
> > On Mon, Apr 24, 2023 at 11:36:47PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> > > On migration, on target we load local ROM file. But actual ROM content
> > > migrates through migration channel. Original ROM content from local
> > > file doesn't matter. But when size mismatch - we have an error like
> > >
> > >   Size mismatch: 0000:00:03.0/virtio-net-pci.rom: 0x40000 != 0x80000: Invalid 
> > > argument
>
> Oh, a 512k rom.  Where does that come from?
>
> The ones shipped by qemu are all between 128k and 256k in size,
> which gets rounded up to 256k (0x40000).  Has not changed since
> we added efi boot rom support ...
>
> If you supply your own versions for some reason you must make sure
> they have identical size on all host machines.

on my ubuntu 22.04:

dpkg -L ipxe-qemu | grep efi-virtio
/usr/lib/ipxe/qemu/efi-virtio.rom

ls -lthr /usr/lib/ipxe/qemu/efi-virtio.rom
-rw-r--r-- 1 root root 512K Jan 13  2022 /usr/lib/ipxe/qemu/efi-virtio.rom

If look inside the file, it's filled with ffff starting from 0x32400

--
Best regards,
Vladimir