Re: [PATCH v7 18/24] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update
From: Zenghui Yu <yuzenghui@huawei.com>
Date: 2020-08-28 09:28:47
Also in:
linux-arm-kernel, linux-iommu, linux-mm, linux-pci
On 2020/5/20 1:54, Jean-Philippe Brucker wrote:
quoted hunk ↗ jump to hunk
@@ -4454,6 +4470,12 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) smmu->features |= ARM_SMMU_FEAT_E2H; } + if (reg & (IDR0_HA | IDR0_HD)) { + smmu->features |= ARM_SMMU_FEAT_HA; + if (reg & IDR0_HD) + smmu->features |= ARM_SMMU_FEAT_HD; + } +
nitpick:
As per the IORT spec (DEN0049D, 3.1.1.2 SMMUv3 node, Table 10), the
"HTTU Override" flag of the SMMUv3 node can override the value in
SMMU_IDR0.HTTU. You may want to check this bit before selecting the
{HA,HD} features and shout if there is a mismatch between firmware and
the SMMU implementation. Just like how ARM_SMMU_FEAT_COHERENCY is
selected.
Thanks,
Zenghui