On Tue, 25 Aug 2020 23:34:48 +0200 daggs <da...@gmx.com> wrote: > Greetings Alex, > > > Sent: Wednesday, August 12, 2020 at 8:04 PM > > From: "Alex Williamson" <alex.william...@redhat.com> > > To: "Patrick O'Callaghan" <p...@usb.ve> > > Cc: vfio-users@redhat.com, "daggs" <da...@gmx.com> > > Subject: Re: [vfio-users] pci passthrough of Intel igp > > > > On Wed, 12 Aug 2020 17:46:33 +0100 > > "Patrick O'Callaghan" <p...@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@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 Legacy IGD assignment still requires 440FX due to Q35 placing it's own device at a conflicting address to the one needed by IGD. The ACS override patch should never be needed for IGD, though it probably tells us the vendor and device IDs that you'd need to patch into the ROM. IGD is always a single function device on the root complex and therefore will always be in its own IOMMU group. Thanks, Alex _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
