Re: [PATCH v2 0/2] PCI: Wait after FLR for devices that don't honor Immediate Readiness

[Linux-Fan]

Alexander Gruhlke writes:

> Since v7.2, VFIO passthrough of a Samsung 990 PRO NVMe [144d:a80c] fails
> on the second VM start, and the device is inaccessible until reboot.  The
> drive advertises Immediate Readiness but returns ~0 for up to 7 ms after
> FLR, so since 10baa9b4df40 ("PCI: Drop unnecessary retries when restoring
> BARs") the config restore after FLR is lost.
>
> Patch 1 ignores Immediate Readiness on that drive.  A 990 EVO Plus
> [144d:a80d] reports the same errors [1], but it isn't confirmed to
> advertise Immediate Readiness, so it's not included.
>
> Patch 2 is independent and keeps pci_dev_wait() from treating ~0 as
> ready with RRS Software Visibility, which also affects the Intel
> [8086:0a54] in the open d591f6804e7e regression.  Hui, Linux-Fan: testing
> patch 2 on that drive would be appreciated.

Sorry to be late to the party -- I only got access to the machine which  
showed the issue today.

I have applied the following two patches:

0f8b5d90d179 ("PCI: Ignore Immediate Readiness on Samsung 990 PRO and 990 EVO Plus NVMe")
e8df1d194c39 ("PCI: Don't treat ~0 as ready in pci_dev_wait() with RRS SV")

These resolve the issue for me.

I an very happy that there is now an upstream solution to this, thank you!

Kind regards
Linux-Fan

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