 where we wait for
QI_DONE with interrupts disabled.  Maybe we need something like
watchdog_hardlockup_touch_cpu() there, along with a timeout in that
loop?

The PCIe r7.0, sec 10.3.1, implementation note suggests the timeout
might be in the 1-2 minute range, which is pretty extreme, but if we
can at least handle timeouts gracefully, we can think about ways to
make them less likely, e.g., by coordinating with FLR and VFIO detach
(maybe the sort of thing Alex alluded to at
https://lore.kernel.org/all/20251223153534.0968cc15.alex@shazbot.org).
I don't know exactly what it would look like to simulate a late
removal event, but it sounds like some kind of complicated
infrastructure that would still be only a 90% solution, which I
wouldn't recommend.[PATCH v2 2/2] iommu/vt-d: Flush dev-IOTLB only when PCIe device is accessible in scalable modeBjorn Helgaas <helgaas@kernel.org> undefined"Tian, Kevin" <kevin.tian@intel.com> undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined undefined