vfio: Do not allow !ops->dma_unmap in vfio_pin/unpin_pages()

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().

Link: https://lore.kernel.org/r/85d622729d8f2334b35d42f1c568df1ededb9171.1690523699.git.nicolinc@nvidia.com
Suggested-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 902f06e..0da8ed8 100644 (file)
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1483,6 +1483,8 @@ 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);
@@ -1520,6 +1522,8 @@ 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);