Re: [PATCH rc v6 2/7] iommu/arm-smmu-v3: Implement is_attach_deferred() for kdump

[Pranjal Shrivastava]

On Wed, May 20, 2026 at 10:03:19AM -0700, Nicolin Chen wrote:
> 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@xxxxxxxxxxxxxxx # v6.12+
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>

Reviewed-by: Pranjal Shrivastava <praan@xxxxxxxxxx>

Thanks,
Praan