Allow (un)plugging whole IOMMU groups at once

[bensmrs]

Is there an existing issue for this?

• There is no existing issue for this feature

What are you currently unable to do

(As discussed in https://discuss.linuxcontainers.org/chat/c/-/7/7958 and following)

Adding a device part of an IOMMU group, e.g. when doing passthrough of a single port in a two-port NIC, results in an error like GenericError: vfio 0000:c6:00.0: group 10 is not viable.

What do you think would need to be added

1. When possible, the error message should be clearer
2. Make it so that PCI passthrough, whatever the way that triggers it (physical NIC, pci device…) checks that all the members of the IOMMU group are to be (un)plugged at once, then does it in a single QMP operation (if that’s even possible)

[kriszos]

I belive that this is some kind of a regression as it was working on 2 of my systems. As far as 7.0 And it stopped working recently.

[bensmrs]

Please look at the dates. This particular issue has always been there (it never was implemented) and one of the test systems on which I noticed it was running 6.19.
Something else may have messed with IOMMU groups on your system (firmware upgrade, different NICs…) if you’re only having problems now.

[kriszos]

You are absolutely right. After some more investigation it actually was ubuntu kernel issue (6.8.0-134-generic) and was fixed yesterday in 6.8.0-136-generic https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2158934 Sorry for cluterring this issue.