RE: [PATCH 1/7] vfio/pci: Disable auto-enable of exclusive INTx IRQ

[Tian, Kevin]

> From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Sent: Thursday, March 7, 2024 5:15 AM
> 
> Currently for devices requiring masking at the irqchip for INTx, ie.
> devices without DisINTx support, the IRQ is enabled in request_irq()
> and subsequently disabled as necessary to align with the masked status
> flag.  This presents a window where the interrupt could fire between
> these events, resulting in the IRQ incrementing the disable depth twice.
> This would be unrecoverable for a user since the masked flag prevents
> nested enables through vfio.
> 
> Instead, invert the logic using IRQF_NO_AUTOEN such that exclusive INTx
> is never auto-enabled, then unmask as required.
> 
> Fixes: 89e1f7d4c66d ("vfio: Add PCI device driver")
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>

CC stable?