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