pciattach Intel HD Iris

[GrayBoltWolf]

So I am trying to attach my Intel iGPU to a windows 8.1 VM. I have a GTX 970 as my primary GPU, so I would like to pass the iGPU to a windows VM for hardware acceleration. I have IOMMU enabled and working, and I am at the stage of attaching the iGPU to the VM. When I enter the command

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VBoxManage modifyvm "win8" --pciattach 00:02.0@01:05.0 

It doesn't return anything like a success or failure. Nothing changes on the VM when I boot it and nothing has changed in the settings. If I detach it with

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VBoxManage modifyvm "win8" --pcidetach 00:02.0@01:05.0

Then it returns :

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gray@Rava-Xubuntu:~$ VBoxManage modifyvm "win8" --pcidetach 00:02.0@01:05.0
VBoxManage: error: No host PCI device 00000010 attached
VBoxManage: error: Details: code VBOX_E_OBJECT_NOT_FOUND (0x80bb0001), component SessionMachine, interface IMachine, callee nsISupports
VBoxManage: error: Context: "DetachHostPCIDevice(iHostAddr)" at line 2981 of file VBoxManageModifyVM.cpp

Any help would be much appreciated. This is version 5.0.4 from the official oracle download page, and the host OS is Xubuntu 14.04.3.

[noteirak]

This is not an answer but merely a disclaimer: keep in mind that PCI pass-through is very experimental and only a handful of feedbacks were ever given.

[GrayBoltWolf]

This is not an answer but merely a disclaimer: keep in mind that PCI pass-through is very experimental and only a handful of feedbacks were ever given.

I am quite aware that this is a relatively unsupported thing. Just looking for any help at all.

Seems strange that VBoxManager doesn't really return anything in the way of errors.

[noteirak]

Trying to reproduce on my machine, this is what I get:

List of PCI devices, let's use 01:00.0 being my 3D card:

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noteirak@Max-Laptop-Linux ~ $ lspci
[...]
01:00.0 3D controller: NVIDIA Corporation GM107M [GeForce GTX 860M] (rev ff)
[...]

Let's create a VM for the occasion and set chipset type to ICH9 (required for PCI attach)

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noteirak@Max-Laptop-Linux ~ $ vboxmanage unregistervm test --delete
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
noteirak@Max-Laptop-Linux ~ $ vboxmanage createvm --name test --register
Virtual machine 'test' is created and registered.
UUID: b77218bd-1b50-46a2-b357-87320aad1338
Settings file: '/home/noteirak/VMs/test/test.vbox'
noteirak@Max-Laptop-Linux ~ $ vboxmanage modifyvm test --chipset ich9
*** I/O APIC must be enabled for ICH9, enabling. ***

Let's try to attach & detach the PCI device:

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noteirak@Max-Laptop-Linux ~ $ vboxmanage modifyvm test --pciattach 01:00.0
noteirak@Max-Laptop-Linux ~ $ vboxmanage modifyvm test --pcidetach 01:00.0
VBoxManage: error: No host PCI device 00000100 attached
VBoxManage: error: Details: code VBOX_E_OBJECT_NOT_FOUND (0x80bb0001), component SessionMachine, interface IMachine, callee nsISupports
VBoxManage: error: Context: "DetachHostPCIDevice(iHostAddr)" at line 2981 of file VBoxManageModifyVM.cpp

So indeed, it doesn't seem to find it, and interesting that the report host PCI device is "00000100" in the error message, while the adress 01:00.0 is used. At this point I start suspecting a bug.

Let's check the VM config to see if it was added in any way:

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noteirak@Max-Laptop-Linux ~ $ grep -iF -A 5 "<hostpci>" /home/noteirak/VMs/test/test.vbox
      <HostPci>
        <Devices>
          <Device host="256" guest="256" name="host01:00.0"/>
        </Devices>
      </HostPci>
      <EmulatedUSB>

So we do have a configuration entry for the PCI device.

Finally, let's see if we have a PCI entry in the VM config with the --machinereadable options so we get the raw output:

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noteirak@Max-Laptop-Linux ~ $ vboxmanage showvminfo test --machinereadable | grep -i pci
AttachedHostPCI=ff:1f.7,ff:1f.7

Indeed we do.

The address seems to be changed by internal mechanism (the numbers 256 seem to play a role in this). Let's use that address instead and see if we can detach:

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noteirak@Max-Laptop-Linux ~ $ vboxmanage modifyvm test --pcidetach ff:1f.7
VBoxManage: error: No host PCI device 0000ffff attached
VBoxManage: error: Details: code VBOX_E_OBJECT_NOT_FOUND (0x80bb0001), component SessionMachine, interface IMachine, callee nsISupports
VBoxManage: error: Context: "DetachHostPCIDevice(iHostAddr)" at line 2981 of file VBoxManageModifyVM.cpp

No dice. so something is definitly fishy here. One last test to confirm a bug:

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noteirak@Max-Laptop-Linux ~ $ vboxmanage modifyvm test --pciattach 01:00.0
noteirak@Max-Laptop-Linux ~ $ 

so I am able to add the same device twice which should not be possible - a check exists in the source code but seems broken then.

Let's recheck the VM config:

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noteirak@Max-Laptop-Linux ~ $ grep -iF -A 5 "<hostpci>" /home/noteirak/VMs/test/test.vbox
      <HostPci>
        <Devices>
          <Device host="256" guest="256" name="host01:00.0"/>
          <Device host="256" guest="256" name="host01:00.0"/>
        </Devices>
      </HostPci>

I will open a ticket on the Bugtracker about this and report back the ticket number.

[GrayBoltWolf]

Trying to reproduce on my machine, this is what I get:

....

I will open a ticket on the Bugtracker about this and report back the ticket number.

Do you know if this used to work on a previous version?

Also, thanks for trying to reproduce it. I really appreciate the help.

[noteirak]

Do you know if this used to work on a previous version?

Yes it used to work before, but it has been a while since someone posted about this with something that can be called "working".
I'm in the process of trying other versions and see when it broke.

[noteirak]

So it works in 4.3.30 and never worked in 5.0.x

[noteirak]

Reported in ticket #14584