From mboxrd@z Thu Jan 1 00:00:00 1970 From: xieyisheng1@huawei.com (Yisheng Xie) Date: Wed, 6 Dec 2017 14:51:59 +0800 Subject: [RFCv2 PATCH 26/36] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update In-Reply-To: <20171006133203.22803-27-jean-philippe.brucker@arm.com> References: <20171006133203.22803-1-jean-philippe.brucker@arm.com> <20171006133203.22803-27-jean-philippe.brucker@arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Jean, On 2017/10/6 21:31, Jean-Philippe Brucker wrote: > If the SMMU supports it and the kernel was built with HTTU support, enable > + if (IS_ENABLED(CONFIG_ARM64_HW_AFDBM) && (reg & (IDR0_HA | IDR0_HD))) { > + smmu->features |= ARM_SMMU_FEAT_HA; > + if (reg & IDR0_HD) > + smmu->features |= ARM_SMMU_FEAT_HD; > + } What is relationship of armv8.1 HW_AFDBM and SMMUv3 HTTU? I mean why we need IS_ENABLED(CONFIG_ARM64_HW_AFDBM) ? If CONFIG_ARM64_HW_AFDBM=y but the process do not support ARMv8.1, should it also enable related feature for SMMUv3? Thanks Yisheng Xie > + > /* > * If the CPU is using VHE, but the SMMU doesn't support it, the SMMU > * will create TLB entries for NH-EL1 world and will miss the >