Re: [Xen-devel] qemu-xen-dir + PCI passthrough = BOOM

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-12-18 at 10:22 -0500, Konrad Rzeszutek Wilk wrote:
> load_roms and bios_load are not set - so it wouldn't even do it.
> It only does it for Bochs BIOS.

Right, this is deliberate.

For ROMBIOS (AKA BOchs BIOS) hvmloader loads the options roms. and I
think ROMBIOS subsequently loads them.

For SeaBIOS it is the BIOS itself which both loads and executes the
ROMS, which is why it is NULL in hvmloader.

The SeaBIOS way is far more like how systems normally work and because
the BIOS is in charge it can do a better job than splitting it between
two entities.

Seems like perhaps I was mistaken about hvmloader+rombios not supporting
loading from the ROM BAR of the device, it does seem to have some
limited support for that (serial controllers and disk controllers only)

hvmloader+rombios does hardcode the VGA bios (rather than getting it
from the emulated devices ROM bar), which is probably what I was
thinking of, that's why people doing VGA passthrough with rombios need
to grab the bios image and build it into hvmloader.

hvmloader+rombios also hardcodes the etherboot rom.

Ian.


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel