[PATCH v1 14/20] iommu/msm_iommu: Implement msm_iommu_domain_test_dev

Nicolin Chen
2025-10-13T00:07:28Z

Move sanity and compatibility tests from the attach_dev callback to the
new test_dev callback function. The IOMMU core makes sure an attach_dev
call must be invoked after a successful test_dev call.

Following the test_dev guideline, replace -EEXIST with -EBUSY.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
drivers/iommu/msm_iommu.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index 819add75a6652..b7b21c97d1bd7 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -391,6 +391,31 @@ static struct iommu_device *msm_iommu_probe_device(struct device *dev)
return &iommu->iommu;
}

+static int msm_iommu_domain_test_dev(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid,
+ struct iommu_domain *old)
+{
+ struct msm_iommu_dev *iommu;
+
+ guard(spinlock_irqsave)(&msm_iommu_lock);
+
+ list_for_each_entry(iommu, &qcom_iommu_devices, dev_node) {
+ struct msm_iommu_ctx_dev *master = list_first_entry(
+ &iommu->ctx_list, struct msm_iommu_ctx_dev, list);
+
+ if (master->of_node != dev->of_node)
+ continue;
+ list_for_each_entry(master, &iommu->ctx_list, list) {
+ if (master->num) {
+ dev_dbg(dev, "domain already attached");
+ return -EBUSY;
+ }
+ }
+ }
+
+ return 0;
+}
+
static int msm_iommu_attach_dev(struct iommu_domain *domain, struct device *dev,
struct iommu_domain *old)
{
@@ -414,11 +439,6 @@ static int msm_iommu_attach_dev(struct iommu_domain *domain, struct device *dev,
goto fail;

list_for_each_entry(master, &iommu->ctx_list, list) {
- if (master->num) {
- dev_err(dev, "domain already attached");
- ret = -EEXIST;
- goto fail;
- }
master->num =
msm_iommu_alloc_ctx(iommu->context_map,
0, iommu->ncb);
@@ -695,6 +715,7 @@ static struct iommu_ops msm_iommu_ops = {
.device_group = generic_device_group,
.of_xlate = qcom_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .test_dev = msm_iommu_domain_test_dev,
.attach_dev = msm_iommu_attach_dev,
.map_pages = msm_iommu_map,
.unmap_pages = msm_iommu_unmap,
--
2.43.0