[RFC PATCH v2 9/9] iommu/arm-smmu-v3: allow multi-SMMU domain installs.

From: Michael Shavit
Date: Tue Aug 22 2023 - 06:58:59 EST


Remove the arm_smmu_domain->smmu handle now that a domain may be
attached to devices with different upstream SMMUs.

Signed-off-by: Michael Shavit <mshavit@xxxxxxxxxx>
---

(no changes since v1)

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 +++-------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 +--
2 files changed, 4 insertions(+), 9 deletions(-)

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 9f8b701771fc3..55c0b8aecfb0a 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2564,13 +2564,9 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)

mutex_lock(&smmu_domain->init_mutex);

- if (!smmu_domain->smmu) {
- smmu_domain->smmu = smmu;
- ret = arm_smmu_domain_finalise(domain, smmu);
- if (ret)
- smmu_domain->smmu = NULL;
- } else if (smmu_domain->smmu != smmu ||
- !arm_smmu_verify_domain_compatible(smmu, smmu_domain))
+ if (!smmu_domain->pgtbl_ops)
+ ret = arm_smmu_domain_finalise(&smmu_domain->domain, smmu);
+ else if (!arm_smmu_verify_domain_compatible(smmu, smmu_domain))
ret = -EINVAL;

mutex_unlock(&smmu_domain->init_mutex);
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 1661d3252bac5..fcf3845f4659c 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -716,8 +716,7 @@ enum arm_smmu_domain_stage {
};

struct arm_smmu_domain {
- struct arm_smmu_device *smmu;
- struct mutex init_mutex; /* Protects smmu pointer */
+ struct mutex init_mutex; /* Protects pgtbl_ops pointer */

struct io_pgtable_ops *pgtbl_ops;
atomic_t nr_ats_masters;
--
2.42.0.rc1.204.g551eb34607-goog