[xubuntu-users] [15.04 64Bit]-"Aw, Snap!" Google Chrome Crashes-AMD Proprietary Display Driver?

[Dave Dodge]

On Wed, Jun 10, 2015 at 01:45:46PM +0200, Petter Adsen wrote:
> Xen might be another option, but I'm not familiar with that. It's
> supposed to be good at PCI passthrough, which might help if it's
> graphics performance you're after.

>From someone who went down that road: don't do it unless you have a
lot of time to spend getting it working.

For GPU performance in Xen you can use "VGA passthrough" to pass a
video card completely through to the guest OS.  For example I was able
to boot the host Linux on one video card, and pass through a second
card to a Windows 8.1 guest.  Windows loaded the proprietary AMD
drivers and could run GPU benchmarks just as if it were a standalone
system.

HOWEVER, VGA passthrough is complicated and finicky.  It's different
from regular PCI passthrough and requires that the CPU, motherboard,
and BIOS all have special support for IOMMU virtualization (in Intel
this is referred to as "VT-d" support).  I picked out parts and built
a dedicated machine specifically for this, and still eventually
abandoned it.

For example I'd been having stability issues with fglrx on another
system so I got an NVIDIA card for the Linux host.  But the card was
too new for the nouveau driver so I had to use the proprietary driver,
which turns out to have lots of issues under Xen.  The nv driver was
buggy when run in a Xen host to the point that X wouldn't even start.
After using some patches so the driver could get far enough along for
the X server to run, OpenGL was still a complete disaster and even
glxgears wouldn't work properly.

The one person I know of who got it all working in Xen actually used
three video cards, in order to run his main Linux system as a guest
where things are more stable.  So he had a cheap card with free
drivers for the Linux host, and then Linux and (I think) Windows
guests each with a high-end passthrough card and proprietary drivers.
One catch is that when the NVIDIA driver detects that it's in a VM it
intentionally disables all gaming cards in order to force you to buy a
more expensive quadro card, so he also had to modify his cards to
trick the driver into thinking thinking he had the quadro version of
the same hardware.

When I got to the point where the next step forward required using a
soldering iron on my new 780Ti, I decided I'd had enough and just
built two machines without virtualization.

                              -Dave Dodge/dododge at dododge.net