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* [REGRESSION] vfio gpu passthrough stopped working
@ 2025-08-07 15:31 cat
  2025-08-07 15:52 ` Greg KH
  0 siblings, 1 reply; 6+ messages in thread
From: cat @ 2025-08-07 15:31 UTC (permalink / raw)
  Cc: regressions, stable

#regzbot introduced: v6.12.34..v6.12.35

After upgrade to kernel 6.12.35, vfio passthrough for my GPU has stopped working within a windows VM, it sees device in device manager but reports that it did not start correctly. I compared lspci logs in the vm before and after upgrade to 6.12.35, and here are the changes I noticed:

- the reported link speed for the passthrough GPU has changed from 2.5 to 16GT/s
- the passthrough GPU has lost it's 'BusMaster' and MSI enable flags
- latency measurement feature appeared

These entries also began appearing within the vm in dmesg when host kernel is 6.12.35 or above:

[    1.963177] nouveau 0000:01:00.0: sec2(gsp): mbox 1c503000 00000001
[    1.963296] nouveau 0000:01:00.0: sec2(gsp):booter-load: boot failed: -5
...
[    1.964580] nouveau 0000:01:00.0: gsp: init failed, -5
[    1.964641] nouveau 0000:01:00.0: init failed with -5
[    1.964681] nouveau: drm:00000000:00000080: init failed with -5
[    1.964721] nouveau 0000:01:00.0: drm: Device allocation failed: -5
[    1.966318] nouveau 0000:01:00.0: probe with driver nouveau failed with error -5


6.12.34 worked fine, and latest 6.12 LTS does not work either. I am using intel CPU and nvidia GPU (for passthrough, and as my GPU on linux system).

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2025-08-08  9:22 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-08-07 15:31 [REGRESSION] vfio gpu passthrough stopped working cat
2025-08-07 15:52 ` Greg KH
2025-08-07 18:31   ` Harshit Mogalapalli
2025-08-08  4:40   ` cat
2025-08-08  9:00     ` cat
2025-08-08  9:22       ` Harshit Mogalapalli

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