On Thu, 2013-04-11 at 13:59 -0400, de...@lavabit.com wrote: > > On Wed, 2013-04-10 at 16:32 -0400, de...@lavabit.com wrote: > >> >> However, turning gfx_passthru off did > >> >> the trick. Win7 started loading with cirrus and switched to HD7750 > >> >> halfway > >> >> through boot proccess. I didn't do any testing just let Windows > >> >> calculate > >> >> its score. The result was 7.4 and Aero was working. > >> > > >> > You should be able to do this with vfio too, use -vga cirrus and don't > >> > use the x-vga option on pci-assign. The x-vga enables legacy VGA > >> > support for boot and primary console, as a secondary head normal PCI > >> > device assignment should be sufficient. > >> > > >> Oh, how I wish it was true! Trying to load with cirrus and vfio-pci > >> results in BSOD: > >> Attemp to reset the display driver and recover from timeout failed. > > > > Is this a fresh windows install? Windows doesn't like change and will > > BSOD pretty easily when attaching graphics to an existing image. > > > >> Trying the old pci-assign with kvm results in non-working GFX. Windows > >> shows code 10 and sometimes code 43 for the card. > > > > What happens if you don't use a q35 machine? Windows is very particular > > about the PCIe type of a device and will often show Code 10 if it > > doesn't have a type compatible with a root complex. Alternatively you > > can use the q35 config in the docs directory with the -readconfig option > > and the bus= option on the pci-assign device to place the graphics > > behind a root port. > > > > After many attempts I have VGA passthrough working. Each test has been > performed in a clean Win7 install with kvm enabled. Installation was done > with i440fx machine and changed to q35 after virtio drivers were > installed. I did that because there's no AHCI driver for q35 yet and win7 > doesn't have drivers for lsi scsi. > > 1. q35/pc, vga=none, vfio-pci, x-vga=on. Nothing on the VM's screen, debug > output can be seen in the previous mails. > 2. q35/pc, vga=cirrus, vfio-pci, x-vga=on. Screen corruption on host > (correction to the previous mails: corruption also happens even in kms > console). Nothing on the VM's screen. > 3. q35/pc, vga=cirrus, vfio-pci, no x-vga. BSOD: Attempt to reset the > display driver and recover from timeout failed. > 4. q35, vga=cirrus, pci-assign. Windows boots, the graphic card doesn't > start: Code 10. > 5. pc, vga=cirrus, pci-assign. IT'S ALIVE! Ironically, this is the oldest > way to assign pci devices in kvm. Why I could make it work previously? > Silly me!
What does your /sys/kernel/iommu_groups look like for the group containing your VGA device? I'm curious if it includes the PCIe root port and whether you're attaching those to vfio-pci or leaving them bound to pcieport. If the former, that may contribute to why you're having problems with vfio-pci. > After some testing I can say that the card can tolerate guest restarts, > but it also can freeze the host in process. I got such a freeze (after a > clean shutdown) once in about 10 restarts. On the other hand, killing the > guest during a heavy 3d benchmark and starting the guest again was fine. > Also, the card fails to clock up after a reboot, which causes poor > performance in heavy loads. Thanks to Xen wiki I found that they "fix" > this by ejecting the graphic card from Windows' panel. Oh, and the last > thing, I once had code 43 after a guest reboot, but rebooting the guest > again fixed it. > > All in all, I'm quite happy now. Just wish that host freeze I had won't > happen again. Is it a bug in qemu, the catalyst driver, or VT-d? > Hopefully, q35 and vfio-pci will work some day. I wonder why q35 + > pci-assign doesn't work, This is likely because pci-assign doesn't mangle the PCI express type to something Windows finds acceptable on a root complex. > and what's the problem with q35/pc + vfio-pci (no > x-vga). If vfio-pci is the direct replacement for pci-assign it must be a > bug in vfio, huh? It's either a bug in vfio or the above configuration issue with the pcieport. I'd appreciate if you could advise how you're configuring the group for use. Thanks, Alex
