[PATCH v7 4/9] 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>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
Reviewed-by: Michael Shavit <mshavit at google.com>
Reviewed-by: Nicolin Chen <nicolinc at nvidia.com>
Reviewed-by: Moritz Fischer <moritzf at google.com>
Reviewed-by: Mostafa Saleh <smostafa at google.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   |  1 +
 3 files changed, 17 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 d159f60480935e..7cf286f7a009fb 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
@@ -569,7 +569,7 @@ 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 d24fa13a52b4e0..f3df1ec8d258dc 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1309,6 +1309,19 @@ void arm_smmu_make_s1_cd(struct arm_smmu_cd *target,
 	target->data[3] = cpu_to_le64(cd->mair);
 }
 
+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);
+}
+
 static void arm_smmu_clean_cd_entry(struct arm_smmu_cd *target)
 {
 	struct arm_smmu_cd used = {};
@@ -2696,9 +2709,7 @@ 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;
 	}
 
@@ -2746,8 +2757,7 @@ 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 bb08f087ba39e4..99fd6f24caa818 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -751,6 +751,7 @@ 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);
 struct arm_smmu_cd *arm_smmu_get_cd_ptr(struct arm_smmu_master *master,
 					u32 ssid);
 void arm_smmu_make_s1_cd(struct arm_smmu_cd *target,
-- 
2.43.2