[PATCH 1/1] iommufd/selftest: Use right iommu_ops for mock device

[Lu Baolu]

In the iommu probe device path, __iommu_probe_device() gets the iommu_ops
for the device from dev->iommu->fwspec if this field has been initialized
before probing. Otherwise, it will lookup the global iommu device list
and use the iommu_ops of the first iommu device which has no
dev->iommu->fwspec. This causes the wrong iommu_ops to be used for the mock
device on x86 platforms where dev->iommu->fwspec is not used.

Preallocate the fwspec for the mock device so that the right iommu ops can
be used.

Fixes: 17de3f5fdd35 ("iommu: Retire bus ops")
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/iommufd/selftest.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index cf3e9fed039e..4eca67b8a5c6 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -611,6 +611,8 @@ static void mock_dev_release(struct device *dev)
 
 static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 {
+	struct iommu_fwspec *fwspec;
+	struct dev_iommu *param;
 	struct mock_dev *mdev;
 	int rc;
 
@@ -621,10 +623,28 @@ static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 	if (!mdev)
 		return ERR_PTR(-ENOMEM);
 
+	/* fwspec and param will be freed in the iommu core */
+	fwspec = kzalloc(sizeof(*fwspec), GFP_KERNEL);
+	if (!fwspec) {
+		kfree(mdev);
+		return ERR_PTR(-ENOMEM);
+	}
+	fwspec->ops = &mock_ops;
+
+	param = kzalloc(sizeof(*param), GFP_KERNEL);
+	if (!param) {
+		kfree(mdev);
+		kfree(fwspec);
+		return ERR_PTR(-ENOMEM);
+	}
+	mutex_init(&param->lock);
+	param->fwspec = fwspec;
+
 	device_initialize(&mdev->dev);
 	mdev->flags = dev_flags;
 	mdev->dev.release = mock_dev_release;
 	mdev->dev.bus = &iommufd_mock_bus_type.bus;
+	mdev->dev.iommu = param;
 
 	rc = dev_set_name(&mdev->dev, "iommufd_mock%u",
 			  atomic_inc_return(&mock_dev_num));
@@ -638,6 +658,8 @@ static struct mock_dev *mock_dev_create(unsigned long dev_flags)
 
 err_put:
 	put_device(&mdev->dev);
+	kfree(param);
+	kfree(fwspec);
 	return ERR_PTR(rc);
 }
 
-- 
2.34.1