[PATCH v5 4/8] iommufd/selftest: Put iopf enablement in domain attach path

Lu Baolu
2025-04-18T08:01:15Z

Update iopf enablement in the iommufd mock device driver to use the new
method, similar to the arm-smmu-v3 driver. Enable iopf support when any
domain with an iopf_handler is attached, and disable it when the domain
is removed.

Add a refcount in the mock device state structure to keep track of the
number of domains set to the device and PASIDs that require iopf.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
---
drivers/iommu/iommufd/selftest.c | 57 ++++++++++++++++++++++++++------
1 file changed, 47 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 18d9a216eb30..6bd0abf9a641 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -58,6 +58,9 @@ enum {
MOCK_PFN_HUGE_IOVA = _MOCK_PFN_START << 2,
};

+static int mock_dev_enable_iopf(struct device *dev, struct iommu_domain *domain);
+static void mock_dev_disable_iopf(struct device *dev, struct iommu_domain *domain);
+
/*
* Syzkaller has trouble randomizing the correct iova to use since it is linked
* to the map ioctl's output, and it has no ide about that. So, simplify things.
@@ -168,6 +171,8 @@ struct mock_dev {
int id;
u32 cache[MOCK_DEV_CACHE_NUM];
atomic_t pasid_1024_fake_error;
+ unsigned int iopf_refcount;
+ struct iommu_domain *domain;
};

static inline struct mock_dev *to_mock_dev(struct device *dev)
@@ -221,6 +226,13 @@ static int mock_domain_nop_attach(struct iommu_domain *domain,
up_write(&mdev->viommu_rwsem);
}

+ rc = mock_dev_enable_iopf(dev, domain);
+ if (rc)
+ return rc;
+
+ mock_dev_disable_iopf(dev, mdev->domain);
+ mdev->domain = domain;
+
return 0;
}

@@ -229,6 +241,7 @@ static int mock_domain_set_dev_pasid_nop(struct iommu_domain *domain,
struct iommu_domain *old)
{
struct mock_dev *mdev = to_mock_dev(dev);
+ int rc;

/*
* Per the first attach with pasid 1024, set the
@@ -256,6 +269,12 @@ static int mock_domain_set_dev_pasid_nop(struct iommu_domain *domain,
}
}

+ rc = mock_dev_enable_iopf(dev, domain);
+ if (rc)
+ return rc;
+
+ mock_dev_disable_iopf(dev, old);
+
return 0;
}

@@ -610,22 +629,42 @@ static void mock_domain_page_response(struct device *dev, struct iopf_fault *evt
{
}

-static int mock_dev_enable_feat(struct device *dev, enum iommu_dev_features feat)
+static int mock_dev_enable_iopf(struct device *dev, struct iommu_domain *domain)
{
- if (feat != IOMMU_DEV_FEAT_IOPF || !mock_iommu_iopf_queue)
+ struct mock_dev *mdev = to_mock_dev(dev);
+ int ret;
+
+ if (!domain || !domain->iopf_handler)
+ return 0;
+
+ if (!mock_iommu_iopf_queue)
return -ENODEV;

- return iopf_queue_add_device(mock_iommu_iopf_queue, dev);
+ if (mdev->iopf_refcount) {
+ mdev->iopf_refcount++;
+ return 0;
+ }
+
+ ret = iopf_queue_add_device(mock_iommu_iopf_queue, dev);
+ if (ret)
+ return ret;
+
+ mdev->iopf_refcount = 1;
+
+ return 0;
}

-static int mock_dev_disable_feat(struct device *dev, enum iommu_dev_features feat)
+static void mock_dev_disable_iopf(struct device *dev, struct iommu_domain *domain)
{
- if (feat != IOMMU_DEV_FEAT_IOPF || !mock_iommu_iopf_queue)
- return -ENODEV;
+ struct mock_dev *mdev = to_mock_dev(dev);
+
+ if (!domain || !domain->iopf_handler)
+ return;
+
+ if (--mdev->iopf_refcount)
+ return;

iopf_queue_remove_device(mock_iommu_iopf_queue, dev);
-
- return 0;
}

static void mock_viommu_destroy(struct iommufd_viommu *viommu)
@@ -770,8 +809,6 @@ static const struct iommu_ops mock_ops = {
.device_group = generic_device_group,
.probe_device = mock_probe_device,
.page_response = mock_domain_page_response,
- .dev_enable_feat = mock_dev_enable_feat,
- .dev_disable_feat = mock_dev_disable_feat,
.user_pasid_table = true,
.viommu_alloc = mock_viommu_alloc,
.default_domain_ops =
--
2.43.0