vfio/mdev: Uses the vfio emulated iommufd ops set in the mdev sample drivers

This harmonizes the no-DMA devices (the vfio-mdev sample drivers) with
the emulated devices (gvt-g, vfio-ap etc.). It makes it easier to add
BIND_IOMMUFD user interface which requires to return an iommufd ID to
represent the device/iommufd bond.

Link: https://lore.kernel.org/r/20230327093351.44505-6-yi.l.liu@intel.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 1ee558c0be2560490a92c513c325edab9f8b970b..890ea101685c18df250478160d83fe55584005ee 100644 (file)
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -32,12 +32,8 @@ int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
                return 0;
        }
 
-       /*
-        * If the driver doesn't provide this op then it means the device does
-        * not do DMA at all. So nothing to do.
-        */
-       if (!vdev->ops->bind_iommufd)
-               return 0;
+       if (WARN_ON(!vdev->ops->bind_iommufd))
+               return -ENODEV;
 
        ret = vdev->ops->bind_iommufd(vdev, ictx, &device_id);
        if (ret)
@@ -119,7 +115,8 @@ EXPORT_SYMBOL_GPL(vfio_iommufd_physical_attach_ioas);
 /*
  * The emulated standard ops mean that vfio_device is going to use the
  * "mdev path" and will call vfio_pin_pages()/vfio_dma_rw(). Drivers using this
- * ops set should call vfio_register_emulated_iommu_dev().
+ * ops set should call vfio_register_emulated_iommu_dev(). Drivers that do
+ * not call vfio_pin_pages()/vfio_dma_rw() have no need to provide dma_unmap.
  */
 
 static void vfio_emulated_unmap(void *data, unsigned long iova,
@@ -127,7 +124,8 @@ static void vfio_emulated_unmap(void *data, unsigned long iova,
 {
        struct vfio_device *vdev = data;
 
-       vdev->ops->dma_unmap(vdev, iova, length);
+       if (vdev->ops->dma_unmap)
+               vdev->ops->dma_unmap(vdev, iova, length);
 }
 
 static const struct iommufd_access_ops vfio_user_ops = {

diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index e54eb752e1ba8912a0c1f86b7b10cb5475633103..19391dda5fbaee29d54078c334f60d4c0304b17b 100644 (file)
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1374,6 +1374,9 @@ static const struct vfio_device_ops mbochs_dev_ops = {
        .write = mbochs_write,
        .ioctl = mbochs_ioctl,
        .mmap = mbochs_mmap,
+       .bind_iommufd   = vfio_iommufd_emulated_bind,
+       .unbind_iommufd = vfio_iommufd_emulated_unbind,
+       .attach_ioas    = vfio_iommufd_emulated_attach_ioas,
 };
 
 static struct mdev_driver mbochs_driver = {

diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index e8400fdab71daaa87861689dff72009ff1539e1d..5f48aef3699568d763eba9bb57078936ea3ec926 100644 (file)
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -663,6 +663,9 @@ static const struct vfio_device_ops mdpy_dev_ops = {
        .write = mdpy_write,
        .ioctl = mdpy_ioctl,
        .mmap = mdpy_mmap,
+       .bind_iommufd   = vfio_iommufd_emulated_bind,
+       .unbind_iommufd = vfio_iommufd_emulated_unbind,
+       .attach_ioas    = vfio_iommufd_emulated_attach_ioas,
 };
 
 static struct mdev_driver mdpy_driver = {

diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index e887de672c526e1eab9844b2da701ed0bb8b7a2c..35460901b9f79ae567c0ba587538343f82c544ec 100644 (file)
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1269,6 +1269,9 @@ static const struct vfio_device_ops mtty_dev_ops = {
        .read = mtty_read,
        .write = mtty_write,
        .ioctl = mtty_ioctl,
+       .bind_iommufd   = vfio_iommufd_emulated_bind,
+       .unbind_iommufd = vfio_iommufd_emulated_unbind,
+       .attach_ioas    = vfio_iommufd_emulated_attach_ioas,
 };
 
 static struct mdev_driver mtty_driver = {