iommufd/selftest: Put iopf enablement in domain attach path

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>
Link: https://lore.kernel.org/r/20250418080130.1844424-5-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 18d9a21..6bd0abf 100644 (file)
--- 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);
 
-       iopf_queue_remove_device(mock_iommu_iopf_queue, dev);
+       if (!domain || !domain->iopf_handler)
+               return;
 
-       return 0;
+       if (--mdev->iopf_refcount)
+               return;
+
+       iopf_queue_remove_device(mock_iommu_iopf_queue, dev);
 }
 
 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 =