[PATCH v6 1/4] vfio: Do not allow !ops->dma_unmap in vfio_pin/unpin_pages()

[Nicolin Chen]

A driver that doesn't implement ops->dma_unmap shouldn't be allowed to do
vfio_pin/unpin_pages(), though it can use vfio_dma_rw() to access an iova
range. Deny !ops->dma_unmap cases in vfio_pin/unpin_pages().

Suggested-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Yi Liu <yi.l.liu@xxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/vfio/vfio_main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 896d8bb49585..48807d587946 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1485,6 +1485,8 @@ int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova,
 	/* group->container cannot change while a vfio device is open */
 	if (!pages || !npage || WARN_ON(!vfio_assert_device_open(device)))
 		return -EINVAL;
+	if (!device->ops->dma_unmap)
+		return -EINVAL;
 	if (vfio_device_has_container(device))
 		return vfio_device_container_pin_pages(device, iova,
 						       npage, prot, pages);
@@ -1522,6 +1524,8 @@ void vfio_unpin_pages(struct vfio_device *device, dma_addr_t iova, int npage)
 {
 	if (WARN_ON(!vfio_assert_device_open(device)))
 		return;
+	if (WARN_ON(!device->ops->dma_unmap))
+		return;
 
 	if (vfio_device_has_container(device)) {
 		vfio_device_container_unpin_pages(device, iova, npage);
-- 
2.40.0