RE: [PATCH rc v8 8/8] iommu: Warn on premature unblock during DMA aliased sibling reset

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Saturday, April 25, 2026 9:15 AM
> 
> When two aliased siblings are in the same iommu_group, they might share
> the
> same RID. The reset functions don't support this case, though it is unclear
> whether there is a real case of having an ATS capable device on a PCI/PCI-X
> bus.
> 
> Theoretically, however, if two aliased devices are resetting concurrently,
> one might be unblocked prematurely in the middle of the reset by the other
> sibling who completes the reset first.
> 
> This isn't a regression from this series but it's better to spit a warning,
> so we can know if such use case is common enough for us to make
> subsequent
> patches for its coverage.
> 
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>