Re: [RFC PATCH 16/19] vfio/pci: Quiesce INTx during PCI recovery

[sashiko-bot@kernel.org]

> Mask INTx when recovery blocks device access. A PCI 2.3 device shares its
> line, so leaving a level interrupt asserted and returning IRQ_NONE would
> storm until note_interrupt() disables the line for every device on it.
> Mask through pci_check_and_mask_intx() and return IRQ_HANDLED instead. A
> device without per-function masking has the line to itself and is quiesced
> through genirq.
> 
> That is a different job from the masking recovery does for itself, so
> vfio_pci_intx_mask_for_recovery() gains a @quiesce argument to tell them
> apart. The handler knows an interrupt has fired but not whether this
> device is the one asserting the shared line, which is what
> pci_check_and_mask_intx() reports, and a false return means the interrupt
> belongs to another device. It is also the user who unmasks afterwards,
> having been sent the eventfd, so the handler does not record the mask as
> one recovery owes.
> [ ... ]
> for an interrupt which cannot arrive, since it only unmasks again after
> receiving one.
> 
> Assisted-by: Claude:claude-opus-5
> 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=16