[PATCH rc v4 2/5] iommu/arm-smmu-v3: Implement is_attach_deferred() for kdump

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Wednesday, April 29, 2026 3:21 PM
> 
> Though the kdump kernel adopts the crashed kernel's stream table, the
> iommu
> core will still try to attach each probed device to a default domain, which
> overwrites the adopted STE and breaks in-flight DMA from that device.
> 
> Implement an is_attach_deferred() callback to prevent this. For each device
> that has STE.V=1 and STE.Cfg!=Abort in the adopted table, defer the default
> domain attachment, until the device driver explicitly requests it.
> 
> Fixes: b63b3439b856 ("iommu/arm-smmu-v3: Abort all transactions if SMMU
> is enabled in kdump kernel")
> Cc: stable at vger.kernel.org # v6.12+
> Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian at intel.com>