RE: [PATCH rc v1 4/4] iommu/arm-smmu-v3: Detect ARM_SMMU_OPT_KDUMP in arm_smmu_device_hw_probe()

Tian, Kevin
2026-04-10T06:23:00Z

> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Friday, April 10, 2026 3:47 AM
> +
> + /*
> + * If SMMU is already active in kdump case, there could be in-flight
> DMA
> + * from devices initiated by the crashed kernel. Mark
> ARM_SMMU_OPT_KDUMP
> + * to let the init functions adopt the crashed kernel's stream table.
> + *
> + * Note that arm_smmu_adopt_strtab() uses memremap that can
> only work on
> + * a coherent SMMU. A non-coherent SMMU has no choice but to
> continue to
> + * abort any in-flight DMA.
> + */
> + if (is_kdump_kernel() && coherent &&
> + (readl_relaxed(smmu->base + ARM_SMMU_CR0) &
> CR0_SMMUEN))
> + smmu->options |= ARM_SMMU_OPT_KDUMP;
> +
> return 0;

A warning message for the non-coherent case?