[vfio-users] Single GPU Passthrough

[Eddie Yen]

That's a good news! I'm exciting about waiting for KVMGT, too.

For direct IGD assignment: You'll need to use remote access
Silly question, is that mean host or guest?
Also I heard about QEMU GTK(or VNC) may support KVMGT, that means it
possible in IGD passthrough?

2016-03-21 23:11 GMT+08:00 Alex Williamson <alex.l.williamson at gmail.com>:

> On Mon, Mar 21, 2016 at 4:54 AM, Okky Hendriansyah <okky.htf at gmail.com>
> wrote:
>
>> On March 21, 2016 at 12:32:28, eric griffith (egriffith92 at gmail.com)
>> wrote:
>>
>>> Details, Alex? What fun technology is enabling this? I didn't think
>>> something like this was currently / soon-to-be possible.
>>> On Mar 20, 2016 23:28, "Alex Williamson" <alex.l.williamson at gmail.com>
>>> wrote:
>>>
>>>> It's coming.  If you have a Broadwell or newer CPU and intend to use
>>>> only Windows guests with IGD as the secondary graphics device VM, you can
>>>> pretty much do it now.  If you have anything older (I'm only intended to go
>>>> back as far as Sandybridge) or want to run a different guest or want to use
>>>> IGD as primary in the guest, you'll need host kernel changes that are
>>>> coming in v4.6, QEMU changes that may or may not make 2.6, and an updated
>>>> SeaBIOS.
>>>>
>>>
>> I think Alex was referring to Intel KVMGT [1].
>>
>
> No, I'm referring to direct IGD assignment.  vGPU via KVMGT is also coming
> and some of the vfio API changes that enable IGD assignment were developed
> as enablers for vGPU support.  For Broadwell and newer, simply assign IGD
> as a secondary graphics device.  Caveats: you won't get a local display,
> you'll need to use remote access (I know, I know), only Windows guests seem
> to work, and you'll need option kvm ignore_msrs=1.  For further support,
> you'll need a new kernel (will be in 4.6-rc1), qemu.git + patches (
> https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg02837.html),
> and a seabios patch (http://patchwork.ozlabs.org/patch/583731/).  Support
> is of course in flux until this is accepted upstream.  I'm trying to make
> configuration as automatic as possible, if IGD is assigned at guest address
> 00:02.0, VGA is available, and an option ROM is available, it assumes
> legacy mode and should work for SandyBridge and newer devices with Linux or
> Windows guests.  If assigned to another guest address it will only enable
> the OpRegion to make the local display work.  OVMF is not yet supported.
> Q35 machine types can only support secondary mode (Broadwell+).  There are
> also still issues to deal with for assigning the host primary graphics
> device, i915 seems to be ok with unbinding the device, but not so much with
> re-binding to the device after use.  So you may want to manually unbind it
> with virsh nodedev-detach prior to starting a VM.  Using pci-stub.ids or
> vfio-pci.ids isn't a clean solution either because other drivers like efifb
> or vesafb will attach to the device regardless.  I typically use a serial
> console, let i915 claim the device, then use virsh nodedev-detach to unbind
> for the VM.  Thanks,
>
> Alex
>
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