Re: [RFC PATCH 01/19] vfio/pci: Add PCI error recovery support state

[sashiko-bot@kernel.org]

> Add the state, the lock and the wait queue that the rest of the series
> needs. Nothing uses any of it yet. The lifecycle and the access guards
> come next, the recovery callbacks later.
> 
> The flags word records what happened in one event. IN_PROGRESS while
> recovery is running, FROZEN if the channel was frozen, RESET if the host
> reset the device, and FAILED if it did not recover. These are internal.
> A later patch reports the same set to userspace along with a sequence
> number, so an event can be told from the one before it.
> 
> Where both locks are held, recovery_lock goes outside memory_lock.
> Recovery has to shut out new device access and wait for whatever is
> already running before it can take memory_lock and revoke the BAR
> mappings. The other way round deadlocks. An access path sits on
> memory_lock waiting for recovery_lock, while recovery sits on
> recovery_lock waiting for memory_lock. So nothing may take recovery_lock
> when it already holds memory_lock.
> 
> Only the generic vfio-pci driver advertises support, so variant drivers
> carry on as they do now. Userspace activation is a separate switch, so
> even on generic vfio-pci nothing changes until userspace asks for it.
> 
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260901093217.8539-1-skolothumtho@nvidia.com?part=1