[PATCH v3 02/10] iommu/arm-smmu-v3: Pass in arm_smmu_make_cd_fn to arm_smmu_set_pasid()
From: Nicolin Chen <hidden>
Date: 2026-02-23 20:28:47
Also in:
linux-iommu, linux-patches, lkml
Subsystem:
arm smmu drivers, arm smmu sva support, iommu subsystem, the rest · Maintainers:
Will Deacon, Joerg Roedel, Linus Torvalds
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@nvidia.com> Signed-off-by: Nicolin Chen <redacted> --- 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