[vfio-users] Guest does not boot OS with GPU passed through, stuck at TianoCore boot splash

Laszlo Ersek lersek at redhat.com
Mon Apr 11 15:48:24 UTC 2016

On 04/10/16 16:46, Blank Field wrote:

> What you can do - convert libvirt xml into a usual qemu command line,
> and add an ISA debug console and check OVMF debug output in it.

* Yes, capturing the OVMF debug log should be the first step when
reporting apparent OVMF issues.

You can get that log without resorting to the raw QEMU command line.
Modify your domain XML like this:

- add the following attribute to the root element of the domain XML:

   xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'  <-- this one

- add the following XML fragment near the end of the domain XML, as a
direct child of the <domain> element:

    <qemu:arg value='-global'/>
    <qemu:arg value='isa-debugcon.iobase=0x402'/>
    <qemu:arg value='-debugcon'/>
    <qemu:arg value='file:/tmp/guest_name.log'/>

This will send the OVMF log to "/tmp/guest_name.log".

* Regarding the specific case: a UEFI oprom for a GPU may easily be
buggy even if it matches the card. If you are experimenting with
"similar" drivers, all bets are off. Please buy a decent card (Alex has
recommended the GTX750 several times; I myself bought one on his
recommendation, and have had zero problems with it). Or else, at least
get an officially supported driver binary from the manufacturer, please.


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