[vfio-users] pci passthrough of Intel igp

[daggs]

Greetings Alex,

> Sent: Friday, August 28, 2020 at 9:11 AM
> From: "daggs" <daggs at gmx.com>
> To: "Alex Williamson" <alex.williamson at redhat.com>
> Cc: vfio-users at redhat.com
> Subject: Re: [vfio-users] pci passthrough of Intel igp
>
> Greetings Alex,
>
> > Sent: Friday, August 28, 2020 at 1:46 AM
> > From: "Alex Williamson" <alex.williamson at redhat.com>
> > To: "daggs" <daggs at gmx.com>
> > Cc: "Patrick O'Callaghan" <poc at usb.ve>, vfio-users at redhat.com
> > Subject: Re: [vfio-users] pci passthrough of Intel igp
> >
> > On Thu, 27 Aug 2020 23:17:52 +0200
> > daggs <daggs at gmx.com> wrote:
> >
> > > Greetings Alex,
> > >
> > > > Sent: Wednesday, August 26, 2020 at 8:02 PM
> > > > From: "Alex Williamson" <alex.williamson at redhat.com>
> > > > To: "daggs" <daggs at gmx.com>
> > > > Cc: "Patrick O'Callaghan" <poc at usb.ve>, vfio-users at redhat.com
> > > > Subject: Re: [vfio-users] pci passthrough of Intel igp
> > > >
> > > > On Wed, 26 Aug 2020 07:27:59 +0200
> > > > daggs <daggs at gmx.com> wrote:
> > > >
> > > > > Greetings Alex,
> > > > >
> > > > > > Sent: Wednesday, August 26, 2020 at 12:54 AM
> > > > > > From: "Alex Williamson" <alex.williamson at redhat.com>
> > > > > > To: "daggs" <daggs at gmx.com>
> > > > > > Cc: "Patrick O'Callaghan" <poc at usb.ve>, vfio-users at redhat.com
> > > > > > Subject: Re: [vfio-users] pci passthrough of Intel igp
> > > > > >
> > > > > > On Tue, 25 Aug 2020 23:34:48 +0200
> > > > > > daggs <daggs at gmx.com> wrote:
> > > > > >
> > > > > > > Greetings Alex,
> > > > > > >
> > > > > > > > Sent: Wednesday, August 12, 2020 at 8:04 PM
> > > > > > > > From: "Alex Williamson" <alex.williamson at redhat.com>
> > > > > > > > To: "Patrick O'Callaghan" <poc at usb.ve>
> > > > > > > > Cc: vfio-users at redhat.com, "daggs" <daggs at gmx.com>
> > > > > > > > Subject: Re: [vfio-users] pci passthrough of Intel igp
> > > > > > > >
> > > > > > > > On Wed, 12 Aug 2020 17:46:33 +0100
> > > > > > > > "Patrick O'Callaghan" <poc at usb.ve> wrote:
> > > > > > > >
> > > > > > > > > On Wed, 2020-08-12 at 18:02 +0200, daggs wrote:
> > > > > > > > > > Greetings,
> > > > > > > > > >
> > > > > > > > > > I have a machine with an Intel igp of HD Graphics 610 [8086:5902].
> > > > > > > > > > I found several discussions on the subject stating that it isn't possible but all of them are several years old.
> > > > > > > > > > so I wanted to know if it is possible to pass it to a vm?
> > > > > > > > > > I'm using kernel 5.4.43, libvirt-6.6.0 and qemu-5.0.0.
> > > > > > > > >
> > > > > > > > > If this is your only GPU, it doesn't make much sense. The idea of
> > > > > > > > > passthrough is to let the VM control an additional GPU, not the main
> > > > > > > > > one.
> > > > > > > >
> > > > > > > > There are plenty of people trying to assign their primary graphics
> > > > > > > > device, it makes perfect sense for someone that doesn't intend to run a
> > > > > > > > graphical environment on the host.  Assigning the primary GPU can be
> > > > > > > > more challenging, but that doesn't mean it isn't done.
> > > > > > > >
> > > > > > > > For daggs, I can only say try it yourself, I don't know of any specific
> > > > > > > > reason it wouldn't work, but direct assignment of IGD is a fair bit of
> > > > > > > > luck anyway since the hardware is constantly changing and we don't
> > > > > > > > really keep up with it.  You might need to play with the x-igd-gms
> > > > > > > > value on the vfio-pci device in QEMU, several people have found that
> > > > > > > > x-igd-gms=1 is necessary on some versions of hardware.  Thanks,
> > > > > > > >
> > > > > > > > Alex
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > > I'm trying to boot the vm up with the igd pass-through, here is my xml: https://dpaste.com/CNDHRLNXC
> > > > > > > the boot ends up with no signal and this is visible in dmesg:
> > > > > > > [   36.181635] DMAR: DRHD: handling fault status reg 3
> > > > > > > [   36.181641] DMAR: [DMA Read] Request device [00:02.0] PASID ffffffff fault addr c6000000 [fault reason 06] PTE Read access is not set
> > > > > > > [   36.182298] DMAR: DRHD: handling fault status reg 3
> > > > > > > [   36.182304] DMAR: [DMA Read] Request device [00:02.0] PASID ffffffff fault addr c603d000 [fault reason 06] PTE Read access is not set
> > > > > > > [   36.183459] DMAR: DRHD: handling fault status reg 3
> > > > > > > [   36.183464] DMAR: [DMA Read] Request device [00:02.0] PASID ffffffff fault addr c603e000 [fault reason 06] PTE Read access is not set
> > > > > > > [   36.184614] DMAR: DRHD: handling fault status reg 3
> > > > > > > [   36.721979] vfio-pci 0000:00:02.0: vfio_ecap_init: hiding ecap 0x1b at 0x100
> > > > > > >
> > > > > > > I've dumped the rom, do I need to run the fixer on it? if so, what is the vid and did?
> > > > > > > than I need to place this <rom file='/home/streamer/vga.rom'/> in the hostdev section?
> > > > > > > I've noticed most of the reports say it works only on i440fx but they
> > > > > > > are all a few years old, is that still the case?
> > > > > > >
> > > > > > > as part of this contexts, I have this in the kernel cmdline:
> > > > > > > pcie_acs_override=id:8086:a170 does it means device 8086:a170 is
> > > > > > > "broken" out of the iommu table?
> > > > > >
> > > > > > If you dump the ROM and provide it via a <rom> tag in the xml, then yes
> > > > > > you need to fix the device ID and checksum, if QEMU loads it from the
> > > > > > device it will do this itself.  You can find the vendor ID (vid) and
> > > > > > device ID (did) with 'lspci -nns 0000:00:02.0", they will be the
> > > > > > numbers in the last set of brackets, ex: [8086:a170].  They're also
> > > > > > available in sysfs under the device:
> > > > > >
> > > > > > $ cat /sys/bus/pci/devices/0000\:00\:02.0/vendor
> > > > > > $ cat /sys/bus/pci/devices/0000\:00\:02.0/device
> > > > >
> > > > > I'll try that and see what happens.
> > > > >
> > > > > > Legacy IGD assignment still requires 440FX due to Q35 placing it's own
> > > > > > device at a conflicting address to the one needed by IGD.
> > > > >
> > > > > duh, my question wasn't clear enough, figures, not the first time I do it.
> > > > > what I meant is do I need Legacy IGD assignment or running the an Q35 machine is enough?
> > > > > the host is booting in uefi mode if it matters to the issue on hand.
> > > >
> > > > "It depends".  You're welcome to try Q35 and see if you can get it to
> > > > work, but the Legacy mode specifically depends on having an address
> > > > on the root bus free which is not available on Q35.  The UPT/Universal
> > > > PassThrough mode is largely abandoned by Intel AFAICT.
> > > unfortunately UPT ends up in the three DMAR errors above and a black screen.
> > >
> > > >
> > > > If your host is booting in UEFI mode then you may not have a BIOS mode
> > > > ROM available.  If you're dumping the ROM, run the parser on it to see
> > > > if it has a BIOS section.  If not, you might need to boot the host in
> > > > non-UEFI mode with a live image and see if you get a different ROM in
> > > > that mode.  Legacy IGD mode also depends on SeaBIOS support.
> > > it doesn't have a bios section afaics:
> > > Valid ROM signature found @0h, PCIR offset 40h
> > >         PCIR: type 0 (x86 PC-AT), vendor: 8086, device: 0406, class: 030000
> > >         PCIR: revision 3, vendor revision: 0
> > >         Last image
> >
> > That is a BIOS image, an UEFI image would be type 3 (EFI).  Note this
> > image is for device ID 0406 where you initially indicated you were
> > using 5902, so I assume you haven't run the fixer on this image.
> >
>
> so it looks like I need to fight the bios, looks like this means war :)
> actually, I did, I ran the parser on the original image as I assumed the fixer changes more than these two values, see:
> $ rom-parser/rom-parser vga.rom
> Valid ROM signature found @0h, PCIR offset 40h
>         PCIR: type 0 (x86 PC-AT), vendor: 8086, device: 5902, class: 030000
>         PCIR: revision 3, vendor revision: 0
>         Last image
>
> Thanks,
>
> Dagg.

I've tried with legacy, still getting the same behavior like in uefi boot (including the errors in dmesg), here is the joint output of dmesg, lspci -nnk and the legacy xml of the vm.
I've booted the system in legacy, extracted the vga rom and fixed the did.

help will be appreciated.

Thanks.

Dagg.