[vfio-users] KVM + QEMU + GPU passthrough (Windows7 Guest)

[Okky Hendriansyah]

So we need a CSM-enabled OVMF builds? My Windows 10 guest script refered to that whitepaper, using pure OVMF build, never tried on Windows 7 though. Just noticed about this CSM-enabled builds, worth to try. Thanks for pointing this.

-- 
Okky Hendriansyah
On September 23, 2015 at 16:49:11, Blank Field (ihatethisfield at gmail.com) wrote:

You can run win7 with ovmf, but you need to follow the whitepaper instructions.

On Sep 23, 2015 11:37 AM, "Okky Hendriansyah" <okky at nostratech.com> wrote:
Good to hear that. Keep in mind that by enabling the Intel VGA Arbitration on the kernel, you lose the DRI capabities (3D acceleration, etc.) on the host graphics card (Intel HD).

If you don't want that, the only way is to pass the GPU without VGA (legacy-free) mode, thus by using a modern OS like Windows 8 onwards that supports UEFI (via OVMF). Using the legacy-free mode we don't need to patch the kernel and we don't lose the DRI capabilities of the host (Intel HD only). Oh yeah, we also need the GPU to support UEFI.

Alex details this on his blog
http://vfio.blogspot.co.id/2014/08/whats-deal-with-vga-arbitration.html?m=1

Best regards,
Okky Hendriansyah

> On Sep 23, 2015, at 14:13, Francisco Menendez <aterfelis at gmail.com> wrote:
>
> Okky.
>
> The arbitration patch did it! Also, by your suggestion, I went back to
> Seabios instead of OVFM.
> Thanks a lot! This was driving me crazy for the past week!
>
> Kind regards.
>
> -Francisco
>
>> On Wed, Sep 23, 2015 at 1:45 PM, Okky Hendriansyah <okky at nostratech.com> wrote:
>> Hmm, I once successful passing through to a Windows 7 guest but with using
>> VGA mode, thus I used the Seabios instead of OVMF, install linux-vfio from
>> AUR to have the kernel patched with necessary Intel VGA Arbitration patches,
>> and enable the i915.enable_hd_vgaarb=1 kernel parameter.
>>
>> Here’s my script when I use Windows 7:
>> http://pastebin.com/5U2VjuEy
>>
>> --
>> Okky Hendriansyah
>>
>> On September 23, 2015 at 11:30:47, Francisco Menendez (aterfelis at gmail.com)
>> wrote:
>>
>> Hello, Okky.
>> Thanks for your reply.
>>
>> I removed the x-vga=on option but there isn't any discernible change.
>> Boots normally, but only displays up until "Starting Windows"
>>
>> On Wed, Sep 23, 2015 at 1:10 PM, Okky Hendriansyah <okky at nostratech.com>
>> wrote:
>>> Hi Francisco,
>>>
>>> It seems that you passthrough in VGA mode (x-vga=on) but you are using
>>> OVMF
>>> also. Have you tried omiting the x-vga=on switch?
>>>
>>> Best regards,
>>> --
>>> Okky Hendriansyah
>>>
>>> On September 23, 2015 at 11:05:44, Francisco Menendez
>>> (aterfelis at gmail.com)
>>> wrote:
>>>
>>> I'm having a bit of an odd issue and would greatly appreciate it if
>>> someone has any clue as of what might be happening.
>>>
>>> The system:
>>> * Intel CPU with VTx and VTd enabled in BIOS
>>> * NVidia GTX 980 - isolated (vfio), to be used by the guest
>>> * Intel graphics for the host (Arch Linux x64)
>>>
>>> What I've done:
>>>
>>> * Added "iommu_intel=on" to the kernel boot command line
>>> * Blacklisted the nouveau driver
>>> * Added the vfio-pci driver and assigned the necessary ids (GPU +
>>> attached HDMI sound)
>>> * Confirmed IOMMU groups ( /sys/kernel/iommu_groups/ -type l output is OK)
>>> * Confirmed vfio-pci capture with dmesg
>>>
>>> What happens:
>>>
>>> After booting windows, I get the GPU displaying the "Starting Windows"
>>> splash screen, with animation and everything. Thus far, I think the
>>> GPU passthrough is successful. However, after that, the screen gets
>>> stuck there while the system keeps booting. I even hear the windows
>>> chime as it starts, but the screen is still showing "Starting Windows"
>>>
>>> If I use emulated VGA, the NVidia card shows "Code 12", but I hear
>>> this is expected if the emulated VGA is turned on.
>>>
>>> The above is also reproducible with the windows installer ( The GPU
>>> output displays: "Windows is loading files" -> "Starting windows" ->
>>> no more screen updates )
>>>
>>> QEMU commandline:
>>>
>>> --------------
>>> qemu-system-x86_64 \
>>> -name windows7 \
>>> -cpu host,kvm=off \
>>> -smp 8,sockets=1,cores=4,threads=2 \
>>> -enable-kvm \
>>> -machine type=pc,accel=kvm,iommu=on \
>>> -m 16G -mem-prealloc -balloon none \
>>> -rtc clock=host,base=utc \
>>> -soundhw hda \
>>> -device
>>> ioh3420,bus=pci.0,addr=1c.0,multifunction=on,port=1,chassis=1,id=root.1
>>> \
>>> -device
>>> vfio-pci,host=01:00.0,bus=root.1,addr=00.0,multifunction=on,x-vga=on
>>> \
>>> -device vfio-pci,host=01:00.1,bus=root.1,addr=00.1 \
>>> -drive
>>>
>>> if=pflash,format=raw,readonly,file=/usr/share/edk2.git/ovmf-x64/OVMF_CODE-pure-efi.fd
>>> \
>>> -drive
>>>
>>> if=pflash,format=raw,file=/usr/share/edk2.git/ovmf-x64/OVMF_VARS-pure-efi.fd
>>> \
>>> -drive file=win7.img,if=ide,format=raw,media=disk \
>>> -monitor stdio \
>>> -device piix3-usb-uhci -device usb-tablet \
>>> -vga none -serial null -parallel null -nodefaults -nodefconfig
>>> ----------------
>>>
>>> Let me know if you need any other information about the setup.
>>> Thank you in advance!
>>>
>>> _______________________________________________
>>> vfio-users mailing list
>>> vfio-users at redhat.com
>>> https://www.redhat.com/mailman/listinfo/vfio-users
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