[PATCH v2 08/11] iommu/arm-smmu-v3: Add HWDBM device feature reporting

[Keqian Zhu]

From: jiangkunkun <jiangkunkun at huawei.com>

We have implemented these interfaces required to support iommu
dirty log tracking. The last step is reporting this feature to
upper user, then the user can perform higher policy base on it.

This adds a new dev feature named IOMMU_DEV_FEAT_HWDBM in iommu
layer. For arm smmuv3, it is equal to ARM_SMMU_FEAT_HD and it is
enabled by default if supported. Other types of IOMMU can enable
it by default or when dev_enable_feature() is called.

Co-developed-by: Keqian Zhu <zhukeqian1 at huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun at huawei.com>
---

changelog:

v2:
 - As dev_has_feature() has been removed from iommu layer, IOMMU_DEV_FEAT_HWDBM
   is designed to be used through "enable" interface.

---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++++
 include/linux/iommu.h                       | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 696df51a3282..cd1627123e80 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2722,6 +2722,8 @@ static bool arm_smmu_dev_has_feature(struct device *dev,
 	switch (feat) {
 	case IOMMU_DEV_FEAT_SVA:
 		return arm_smmu_master_sva_supported(master);
+	case IOMMU_DEV_FEAT_HWDBM:
+		return !!(master->smmu->features & ARM_SMMU_FEAT_HD);
 	default:
 		return false;
 	}
@@ -2738,6 +2740,8 @@ static bool arm_smmu_dev_feature_enabled(struct device *dev,
 	switch (feat) {
 	case IOMMU_DEV_FEAT_SVA:
 		return arm_smmu_master_sva_enabled(master);
+	case IOMMU_DEV_FEAT_HWDBM:
+		return arm_smmu_dev_has_feature(dev, feat);
 	default:
 		return false;
 	}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 4f7db5d23b23..88584a2d027c 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -160,6 +160,7 @@ struct iommu_resv_region {
 enum iommu_dev_features {
 	IOMMU_DEV_FEAT_AUX,	/* Aux-domain feature */
 	IOMMU_DEV_FEAT_SVA,	/* Shared Virtual Addresses */
+	IOMMU_DEV_FEAT_HWDBM,	/* Hardware Dirty Bit Management */
 };
 
 #define IOMMU_PASID_INVALID	(-1U)
-- 
2.19.1