vfio: Replace the DMA unmapping notifier with a callback

Instead of having drivers register the notifier with explicit code just
have them provide a dma_unmap callback op in their driver ops and rely on
the core code to wire it up.

Suggested-by: Christoph Hellwig <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Tony Krowiak <[email protected]>
Reviewed-by: Eric Farman <[email protected]>
Reviewed-by: Zhenyu Wang <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alex Williamson <[email protected]>

1 files changed, 4 insertions, 17 deletions

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 4d26e149db81..1f9fc7a9be9e 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -49,6 +49,7 @@ struct vfio_device {
 	unsigned int open_count;
 	struct completion comp;
 	struct list_head group_next;
+	struct notifier_block iommu_nb;
 };
 
 /**
@@ -65,6 +66,8 @@ struct vfio_device {
  * @match: Optional device name match callback (return: 0 for no-match, >0 for
  *         match, -errno for abort (ex. match with insufficient or incorrect
  *         additional args)
+ * @dma_unmap: Called when userspace unmaps IOVA from the container
+ *             this device is attached to.
  * @device_feature: Optional, fill in the VFIO_DEVICE_FEATURE ioctl
  */
 struct vfio_device_ops {
@@ -80,6 +83,7 @@ struct vfio_device_ops {
 	int	(*mmap)(struct vfio_device *vdev, struct vm_area_struct *vma);
 	void	(*request)(struct vfio_device *vdev, unsigned int count);
 	int	(*match)(struct vfio_device *vdev, char *buf);
+	void	(*dma_unmap)(struct vfio_device *vdev, u64 iova, u64 length);
 	int	(*device_feature)(struct vfio_device *device, u32 flags,
 				  void __user *arg, size_t argsz);
 };
@@ -164,23 +168,6 @@ int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova,
 		void *data, size_t len, bool write);
 
-/* each type has independent events */
-enum vfio_notify_type {
-	VFIO_IOMMU_NOTIFY = 0,
-};
-
-/* events for VFIO_IOMMU_NOTIFY */
-#define VFIO_IOMMU_NOTIFY_DMA_UNMAP	BIT(0)
-
-int vfio_register_notifier(struct vfio_device *device,
-			   enum vfio_notify_type type,
-			   unsigned long *required_events,
-			   struct notifier_block *nb);
-int vfio_unregister_notifier(struct vfio_device *device,
-			     enum vfio_notify_type type,
-			     struct notifier_block *nb);
-
-
 /*
  * Sub-module helpers
  */