[PATCH v3 02/10] iommu/arm-smmu-v3: Pass in arm_smmu_make_cd_fn to arm_smmu_set_pasid()

[Nicolin Chen]

To install a domain (CD) to a substream, the common flow in the driver is:
 - Make an S1 or SVA CD outside arm_smmu_asid_lock
 - Invoke arm_smmu_set_pasid() where it takes arm_smmu_asid_lock, and fix
   the ASID in the CD.

The reason for such a flow is for the timing of arm_smmu_asid_lock, since
it was too early to take the mutex outside the function.

Tidy it up by passing in a function pointer for CD making,, which supports
both existing functions: arm_smmu_make_s1_cd() and arm_smmu_make_sva_cd().

Then arm_smmu_set_pasid() can make a CD inside the lock where ASID is safe
to access.

Suggested-by: Jason Gunthorpe <jgg at nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  7 ++++++-
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  4 ++--
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 19 ++++---------------
 3 files changed, 12 insertions(+), 18 deletions(-)

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 dd5d2b5acf664..e3a66e6bc303e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1076,9 +1076,14 @@ void arm_smmu_write_cd_entry(struct arm_smmu_master *master, int ssid,
 			     struct arm_smmu_cd *cdptr,
 			     const struct arm_smmu_cd *target);
 
+typedef void (*arm_smmu_make_cd_fn)(struct arm_smmu_cd *target,
+				    struct arm_smmu_master *master,
+				    struct arm_smmu_domain *smmu_domain);
+
 int arm_smmu_set_pasid(struct arm_smmu_master *master,
 		       struct arm_smmu_domain *smmu_domain, ioasid_t pasid,
-		       struct arm_smmu_cd *cd, struct iommu_domain *old);
+		       struct arm_smmu_cd *cd, struct iommu_domain *old,
+		       arm_smmu_make_cd_fn fn);
 
 void arm_smmu_domain_inv_range(struct arm_smmu_domain *smmu_domain,
 			       unsigned long iova, size_t size,
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 414fc899140f7..4370cb88c57cf 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
@@ -273,8 +273,8 @@ static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain,
 	 * This does not need the arm_smmu_asid_lock because SVA domains never
 	 * get reassigned
 	 */
-	arm_smmu_make_sva_cd(&target, master, smmu_domain);
-	ret = arm_smmu_set_pasid(master, smmu_domain, id, &target, old);
+	ret = arm_smmu_set_pasid(master, smmu_domain, id, &target, old,
+				 arm_smmu_make_sva_cd);
 
 	mmput(domain->mm);
 	return ret;
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 b10a68565e9df..7c075e64f842e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3733,13 +3733,8 @@ static int arm_smmu_s1_set_dev_pasid(struct iommu_domain *domain,
 	if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
 		return -EINVAL;
 
-	/*
-	 * We can read cd.asid outside the lock because arm_smmu_set_pasid()
-	 * will fix it
-	 */
-	arm_smmu_make_s1_cd(&target_cd, master, smmu_domain);
 	return arm_smmu_set_pasid(master, to_smmu_domain(domain), id,
-				  &target_cd, old);
+				  &target_cd, old, arm_smmu_make_s1_cd);
 }
 
 static void arm_smmu_update_ste(struct arm_smmu_master *master,
@@ -3769,7 +3764,8 @@ static void arm_smmu_update_ste(struct arm_smmu_master *master,
 
 int arm_smmu_set_pasid(struct arm_smmu_master *master,
 		       struct arm_smmu_domain *smmu_domain, ioasid_t pasid,
-		       struct arm_smmu_cd *cd, struct iommu_domain *old)
+		       struct arm_smmu_cd *cd, struct iommu_domain *old,
+		       arm_smmu_make_cd_fn arm_smmu_make_cd_fn)
 {
 	struct iommu_domain *sid_domain =
 		iommu_driver_get_domain_for_dev(master->dev);
@@ -3800,14 +3796,7 @@ int arm_smmu_set_pasid(struct arm_smmu_master *master,
 	if (ret)
 		goto out_unlock;
 
-	/*
-	 * We don't want to obtain to the asid_lock too early, so fix up the
-	 * caller set ASID under the lock in case it changed.
-	 */
-	cd->data[0] &= ~cpu_to_le64(CTXDESC_CD_0_ASID);
-	cd->data[0] |= cpu_to_le64(
-		FIELD_PREP(CTXDESC_CD_0_ASID, smmu_domain->cd.asid));
-
+	arm_smmu_make_cd_fn(cd, master, smmu_domain);
 	arm_smmu_write_cd_entry(master, pasid, cdptr, cd);
 	arm_smmu_update_ste(master, sid_domain, state.ats_enabled);
 
-- 
2.43.0