[vfio-users] Console output on the host stops after launching a VM with vfio GPU

[Roman Mamedov]

On Tue, 9 May 2017 16:21:59 -0600
Alex Williamson <alex.williamson at redhat.com> wrote:

> http://awilliam.github.io/presentations/KVM-Forum-2014/#/
> 
> On the "Issues:" slide, the line about drivers not participating
> (vgacon)... that's the problem.  Watch the video, also see:
> 
> http://vfio.blogspot.com/2014/08/whats-deal-with-vga-arbitration.html
> 
> The host needs to be running a driver that participates in VGA
> arbitration or else the first access to VGA space by the guest is going
> to switch VGA routing to the assigned device and the driver running the
> host graphics will never switch it back.  An even better option is to
> use a UEFI capable graphics card with an OVMF guest and drop the x-vga
> option.  Thanks,

Thanks for the hint!

I was able to replace the host's boot video card with an old Radeon X300SE --
that one supports high-resolution KMS-based console with the 'radeon' driver,
and unlike the legacy VGA console, the KMS one keeps working fine even when a
VFIO guest is launched. Hooray!

-- 
With respect,
Roman