[RFC PATCH v6 03/11] iommufd/device: Associate KVM file pointer with iommufd_device

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

From: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

TSM vDevice support needs access to the KVM associated with a VFIO device
after the device has been bound to iommufd.

Extend iommufd_device_bind() to accept the device's KVM file and store it
in the iommufd_device. The KVM file reference is owned by VFIO and is
already held for the duration of the device open path.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
[nicolinc: fix build error in iommufd_test_mock_domain()]
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
[aneesh.kumar: Switch to use kvm_file]
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 drivers/iommu/iommufd/device.c          | 7 ++++++-
 drivers/iommu/iommufd/iommufd_private.h | 2 ++
 drivers/iommu/iommufd/selftest.c        | 2 +-
 drivers/vfio/iommufd.c                  | 3 ++-
 include/linux/iommufd.h                 | 4 +++-
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 170a7005f0bc..718abdc0e627 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -203,6 +203,7 @@ void iommufd_device_destroy(struct iommufd_object *obj)
  * iommufd_device_bind - Bind a physical device to an iommu fd
  * @ictx: iommufd file descriptor
  * @dev: Pointer to a physical device struct
+ * @kvm_file: VM file if device belongs to a KVM VM
  * @id: Output ID number to return to userspace for this device
  *
  * A successful bind establishes an ownership over the device and returns
@@ -216,7 +217,9 @@ void iommufd_device_destroy(struct iommufd_object *obj)
  * The caller must undo this with iommufd_device_unbind()
  */
 struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
-					   struct device *dev, u32 *id)
+					   struct device *dev,
+					   struct file *kvm_file,
+					   u32 *id)
 {
 	struct iommufd_device *idev;
 	struct iommufd_group *igroup;
@@ -266,6 +269,8 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
 	if (!iommufd_selftest_is_mock_dev(dev))
 		iommufd_ctx_get(ictx);
 	idev->dev = dev;
+	/* reference is already taken in vfio_df_ioctl_bind_iommufd() */
+	idev->kvm_file = kvm_file;
 	idev->enforce_cache_coherency =
 		device_iommu_capable(dev, IOMMU_CAP_ENFORCE_CACHE_COHERENCY);
 	/* The calling driver is a user until iommufd_device_unbind() */
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 43fbc5bed8de..6cf76f7ca379 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -488,6 +488,8 @@ struct iommufd_device {
 	struct list_head group_item;
 	/* always the physical device */
 	struct device *dev;
+	/* ..and the VM file if available */
+	struct file *kvm_file;
 	bool enforce_cache_coherency;
 	struct iommufd_vdevice *vdev;
 	bool destroying;
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index af07c642a526..a193390f9d07 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -1069,7 +1069,7 @@ static int iommufd_test_mock_domain(struct iommufd_ucmd *ucmd,
 		goto out_sobj;
 	}
 
-	idev = iommufd_device_bind(ucmd->ictx, &sobj->idev.mock_dev->dev,
+	idev = iommufd_device_bind(ucmd->ictx, &sobj->idev.mock_dev->dev, NULL,
 				   &idev_id);
 	if (IS_ERR(idev)) {
 		rc = PTR_ERR(idev);
diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index a38d262c6028..d2d0bd9382a1 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -119,7 +119,8 @@ int vfio_iommufd_physical_bind(struct vfio_device *vdev,
 {
 	struct iommufd_device *idev;
 
-	idev = iommufd_device_bind(ictx, vdev->dev, out_device_id);
+	idev = iommufd_device_bind(ictx, vdev->dev, vdev->kvm_file,
+				   out_device_id);
 	if (IS_ERR(idev))
 		return PTR_ERR(idev);
 	vdev->iommufd_device = idev;
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 6e7efe83bc5d..0a0bb4abfbd2 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -59,7 +59,9 @@ struct iommufd_object {
 };
 
 struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
-					   struct device *dev, u32 *id);
+					   struct device *dev,
+					   struct file *kvm_file,
+					   u32 *id);
 void iommufd_device_unbind(struct iommufd_device *idev);
 
 int iommufd_device_attach(struct iommufd_device *idev, ioasid_t pasid,
-- 
2.43.0