[PATCH rc v4 4/5] iommu/arm-smmu-v3: Retain CR0_SMMUEN during kdump device reset

[Tian, Kevin]

> From: Nicolin Chen <nicolinc at nvidia.com>
> Sent: Wednesday, April 29, 2026 3:21 PM
> 
> 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 CR0_SMMUEN in kdump case. Then,
> preserve that when enabling the command queue.
> 
> Clear latched gerror bits if necessary.
> 
> 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>