Re: [PATCH v11 09/11] iommu/arm-smmu-v3: Retain CR0_SMMUEN during kdump device reset

[Jason Gunthorpe]

On Mon, 05 Oct 2026 12:30:52 -0700, Nicolin Chen <nicolinc@xxxxxxxxxx> wrote:
> When ARM_SMMU_OPT_KDUMP_ADOPT is detected, do not disable SMMUEN and skip
> the CR1/CR2/STRTAB_BASE update sequence in arm_smmu_device_reset(). Those
> register writes are all CONSTRAINED UNPREDICTABLE while CR0_SMMUEN==1, so
> leaving them intact lets in-flight DMAs continue to be translated by the
> adopted stream table.
> 
> Initialize 'enables' to 0, so it can carry the retained CR0 fields in the
> kdump case, clearing only the queue enable bits. Then, preserve them when
> enabling the command queue.
> 
> [...]

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

-- 
Jason