[SATLUG] kvm pci passthrough

Mark Mayfield mayfield_mark at gvtc.com
Tue Jan 29 14:52:08 CST 2013


Something happened with my email and I had had to transfer my satlug 
account to a different address.


Anyway I had a very productive experience with kvm recently. I was using 
xen for a while but I stumbled onto spice and have been loving it. 
Libvirt, spice and pulseaudio work well together without a fight, unlike 
vnc. The video driver for spice, qxl is way better than cirrus and the 
other video drivers. The spice vdagent provides copy and paste ability 
between the host and guest. These improvements make it much more usable 
for day to day desktop virtualization.

Having finally gotten the video card I've been needing to complete my 
gaming virtual machine project that's been in the works for about a 
year, I decided to give kvm a shot instead of xen. After stumbling upon 
an option I had to pass to the kvm module I successfully passed a Radeon 
HD 6850 to a Windows 8 virtual machine. After getting the video card 
installed, running the windows experience tool and installing game I was 
a little disappointed. I did achieve a 5.9 rating but the game movement 
was less than ideal. After some tinkering I figured out that the virtual 
keyboard and mouse couldn't keep up with the game. I managed to pass 
through a usb controller and use a dedicated keyboard and mouse for the 
virtual.

The virtual machine runs Halo, Assassins Creed 2, Crysis and Skyrim 
(medium settings). The only real glitch is that I have to reboot the 
host to reboot the guest. If I try to reboot the guest without rebooting 
the host the guest crashes.

I will post a screenshot of the virtual machine later.

FYI for performance I'm using a raw disk image with no cache, virtio 
storage and network drivers, hugepages and elevator=noop.


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