Re: Code 12 with VGA passthrough, even with qemu-traditional

[Richie <listmail@triad.rr.com>]

On 8/21/2014 6:01 PM, Sander Eikelenboom wrote:
> I have a system (amd based) with radeon HD6950 that is able to be 
> passed through to a linux HVM guest (although you only get output 
> after the kernel loads the radeon KMS/DRM driver since it's secondary 
> passthrough). This is _not_ the primary graphics card from the host 
> (got another radeon for dom0).

Just chiming in here with a side note.

I decided to test out KVM + vfio on 3.16 with acs + intel igd patches 
and passed through my secondary card.   It was successful and I had the 
Seabios screen show up on my secondary VGA card (GTX 660ti).   It 
maintained video throughout the boot process including the Windows 7 
installer.  The only catch really was that since the host was on qemu 
2.0.0 and did not have the -cpu kvm=off switch (to hide kvm) I had to 
use Nvidia driver 335.x (or earlier).  Basic 3D tests have proved 
sucessfull and pt continues to work after subsequent guest reboots.

Now to be clear, I am partial to Xen.   My thinking is that at some 
point (or perhaps even now) that using the qemu upstream device model 
with Xen will yield this type of capability.  I am not so familiar with 
vfio or even pt with KVM.  There just happened to be the right guide out 
there on the net that could fill in the blanks.