Ubuntu 14.04 / Xen 4.4 improved VGA passthrough for AMD cards

[tuxinteger]

Just a quick finding on the ati pci passthorugh and Xen .

Reduce ram to 6098Gb or less in the config.
Reduce your ram speed to 1333Mhz .

The amd /ati drivers do seem to like any o/c within the host.


You might find it all works !.

The mem limit is somewhat more complex to work around,is this the Intel fx emulation limitation ?.

HTH

[tuxinteger]

Just a quick finding on the ati pci passthorugh and Xen .

Reduce ram to 6098Gb or less in the config.
Reduce your ram speed to 1333Mhz .


The amd /ati drivers do seem to like any o/c within the host.


You might find it all works !.

The mem limit is somewhat more complex to work around,is this the Intel fx emulation limitation ?.

HTH

Also reduce video card memory clock to 1330Mhz if it is higher as this helps mitigate the atikmdag and driver issues.

[redger]

I finally created a passthrough guide for UEFI Windows guests under KVM & libvirt
http://ubuntuforums.org/showthread.p...9#post13235279

much of the complexity comes from trying to run everything as a normal user (as opposed to root), though it does make for some interesting changes in libvirt and apparmor configurations

gratefulfor any feedback and/or advice

vga passthrough using KVM seems to work best with AMD graphics - NVIDIA's Windows drivers are causing problems ... and the easiest / most stable form is to use UEFI to boot the guest (doesn't mean the host needs to be booted via UEFI) as this avoids the whole legacy VGA mess. It also means that most things can be done with libvirt / virt-manager - even on Ubuntu Trusty LTS

[noriss]

After using 6-7 month VGA passthrough my windows amd drivers boke windows 7. I was using 15.2 beta drivers because, it was only version that work that the time.

Anyone else having same problem?

hardware:
GPU: ATI Radeon R9 270 DD
CPU: AMD FX 8320
motherboard: Gigabyte GA-990XA-UD3 990X AM3+ ATX