[vfio-users] VGA Passthrough fails without NoSnoop patch

[Javier Celaya]

My 480 supports UEFI. In fact, everything works fine with QEMU 2.2 and the
NoSnoop patch. I used Windows 7 with BIOS and the NVIDIA card in the past,
but switched to UEFI to avoid the VGA arbiter issues. With BIOS, I had the
same problem.

El 29/1/2017 21:01, "Nick Sarnie" <commendsarnex at gmail.com> escribió:

> Have you tried a BIOS install and setting x-vga=on? With my 480, there is
> no UEFI image or it got corrupted somehow, so I need to pass a UEFI vbios I
> downloaded to see the screen if I use UEFI. With BIOS, x-vga=on works.
>
>
>
> On Sun, Jan 29, 2017 at 2:55 PM, Javier Celaya <jcelaya at gmail.com> wrote:
>
>> Hello list
>>
>> I've been looking for it, but I cannot find a solution to this problem. I
>> have a working Windows 10 VM with UEFI boot, which I pass an AMD Radeon RX
>> 480. It also worked with a NVIDIA GTX 550Ti I had before. The thing is, it
>> only works with a QEMU 2.2 patched with the NoSnoop fix. With any later
>> release of QEMU, or without the patch, the VM:
>> - Throws an Error 43 with the NVIDIA card.
>> - Goes black on boot and reboots some seconds later with the AMD card
>> The vfio FAQ says that patch is not needed with a later release of QEMU,
>> so I'm wondering what I'm doing wrong...
>>
>> My hardware is an Intel i5 2500, ASUS motherboard with a Z68 chipset,
>> 16GB of RAM. Both graphics cards appear in their own iommu group with the
>> HDMI sound card.
>>
>> My QEMU command line is:
>>
>> src/qemu/build-2.2-NoSnoop/x86_64-softmmu/qemu-system-x86_
>> 64
>>
>>         -nodefaults -no-user-config
>>
>>
>>         -enable-kvm -m 8192
>>
>>
>>         -cpu Opteron_G1,+cx16,+lahf_lm,kvm=off
>>
>>
>>         -M q35
>>
>>
>>         -smp 4,sockets=1,cores=4,threads=1
>>         -realtime mlock=on -rtc base=localtime,driftfix=slew
>>         -drive file="OVMF_CODE-pure-efi.fd",i
>> f=pflash,format=raw,unit=0,readonly=on
>>         -drive file="OVMF_VARS-pure-efi.fd",if=pflash,format=raw,unit=1
>>         -drive file="$HD",id=disk1,if=virtio,cache=none
>>         -netdev bridge,id=netuser,br=br0
>>         -device virtio-net-pci,netdev=netuser,
>> id=net0,mac=52:54:00:72:75:9e
>>         -device ich9-intel-hda,id=sound0
>>         -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0
>>         -device ioh3420,bus=pcie.0,multifunction=on,port=1,chassis=1,id=
>> root.0
>>         -usbdevice $JOYPAD
>>         -usbdevice $KEYBOARD
>>         -usbdevice $MOUSE
>>
>>         -mem-path $MEM_PATH
>>
>>         -nographic -vga none
>>         -device vfio-pci,host=01:00.0,id=hostd
>> ev0,bus=root.0,multifunction=on,x-vga=on
>>         -device vfio-pci,host=01:00.1,id=hostdev1,bus=pcie.0
>>
>> I have tried, with the same results:
>> - Using the pc-i440fx machine
>> - Connecting the HDMI sound card to another bus
>> - Not connecting the HDMI sound card at all
>> - Using -cpu host (Windows 10 hangs with this configuration)
>> - Using -cpu core2duo
>>
>> Any other idea?
>> Thank you
>>
>> Javi
>>
>> _______________________________________________
>> vfio-users mailing list
>> vfio-users at redhat.com
>> https://www.redhat.com/mailman/listinfo/vfio-users
>>
>>
>
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