[PATCH v5 06/27] iommu/arm-smmu-v3: Consolidate clearing a CD table entry

[Jason Gunthorpe]

A cleared entry is all 0's. Make arm_smmu_clear_cd() do this sequence.

If we are clearing an entry and for some reason it is not already
allocated in the CD table then something has gone wrong.

Tested-by: Nicolin Chen <nicolinc at nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
---
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  2 +-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 20 ++++++++++++++-----
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  2 ++
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 347c2fdd865c1a..bb9bb6fd7914ce 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -558,7 +558,7 @@ void arm_smmu_sva_remove_dev_pasid(struct iommu_domain *domain,
 
 	mutex_lock(&sva_lock);
 
-	arm_smmu_write_ctx_desc(master, id, NULL);
+	arm_smmu_clear_cd(master, id);
 
 	list_for_each_entry(t, &master->bonds, list) {
 		if (t->mm == mm) {
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 237fd6d92c880b..3fb4a1523d1d3f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1303,6 +1303,19 @@ static void arm_smmu_write_cd_entry(struct arm_smmu_master *master, int ssid,
 	arm_smmu_write_entry(&cd_writer.writer, cdptr->data, target->data);
 }
 
+void arm_smmu_clear_cd(struct arm_smmu_master *master, ioasid_t ssid)
+{
+	struct arm_smmu_cd target = {};
+	struct arm_smmu_cd *cdptr;
+
+	if (!master->cd_table.cdtab)
+		return;
+	cdptr = arm_smmu_get_cd_ptr(master, ssid);
+	if (WARN_ON(!cdptr))
+		return;
+	arm_smmu_write_cd_entry(master, ssid, cdptr, &target);
+}
+
 int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid,
 			    struct arm_smmu_ctx_desc *cd)
 {
@@ -2702,9 +2715,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	case ARM_SMMU_DOMAIN_S2:
 		arm_smmu_make_s2_domain_ste(&target, master, smmu_domain);
 		arm_smmu_install_ste_for_dev(master, &target);
-		if (master->cd_table.cdtab)
-			arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
-						      NULL);
+		arm_smmu_clear_cd(master, IOMMU_NO_PASID);
 		break;
 	}
 
@@ -2752,8 +2763,7 @@ static int arm_smmu_attach_dev_ste(struct device *dev,
 	 * arm_smmu_domain->devices to avoid races updating the same context
 	 * descriptor from arm_smmu_share_asid().
 	 */
-	if (master->cd_table.cdtab)
-		arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID, NULL);
+	arm_smmu_clear_cd(master, IOMMU_NO_PASID);
 	return 0;
 }
 
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 7078ed569fd4d3..87a7b57f566fbc 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -749,6 +749,8 @@ extern struct xarray arm_smmu_asid_xa;
 extern struct mutex arm_smmu_asid_lock;
 extern struct arm_smmu_ctx_desc quiet_cd;
 
+void arm_smmu_clear_cd(struct arm_smmu_master *master, ioasid_t ssid);
+
 int arm_smmu_write_ctx_desc(struct arm_smmu_master *smmu_master, int ssid,
 			    struct arm_smmu_ctx_desc *cd);
 void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
-- 
2.43.2