@@ -347,6 +347,14 @@ static long vhost_vdpa_set_config(struct vhost_vdpa *v,
return 0;
}
+static bool vhost_vdpa_can_stop(const struct vhost_vdpa *v)
+{
+ struct vdpa_device *vdpa = v->vdpa;
+ const struct vdpa_config_ops *ops = vdpa->config;
+
+ return ops->stop;
+}
+
static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
{
struct vdpa_device *vdpa = v->vdpa;
@@ -575,7 +583,11 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
if (cmd == VHOST_SET_BACKEND_FEATURES) {
if (copy_from_user(&features, featurep, sizeof(features)))
return -EFAULT;
- if (features & ~VHOST_VDPA_BACKEND_FEATURES)
+ if (features & ~(VHOST_VDPA_BACKEND_FEATURES |
+ BIT_ULL(VHOST_BACKEND_F_STOP)))
+ return -EOPNOTSUPP;
+ if ((features & BIT_ULL(VHOST_BACKEND_F_STOP)) &&
+ !vhost_vdpa_can_stop(v))
return -EOPNOTSUPP;
vhost_set_backend_features(&v->vdev, features);
return 0;
@@ -624,6 +636,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
break;
case VHOST_GET_BACKEND_FEATURES:
features = VHOST_VDPA_BACKEND_FEATURES;
+ if (vhost_vdpa_can_stop(v))
+ features |= BIT_ULL(VHOST_BACKEND_F_STOP);
if (copy_to_user(featurep, &features, sizeof(features)))
r = -EFAULT;
break;
@@ -161,5 +161,7 @@ struct vhost_vdpa_iova_range {
* message
*/
#define VHOST_BACKEND_F_IOTLB_ASID 0x3
+/* Stop device from processing virtqueue buffers */
+#define VHOST_BACKEND_F_STOP 0x4
#endif
Userland knows if it can stop the device or not by checking this feature bit. It's only offered if the vdpa driver backend implements the stop() operation callback, and try to set it if the backend does not offer that callback is an error. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> --- drivers/vhost/vdpa.c | 16 +++++++++++++++- include/uapi/linux/vhost_types.h | 2 ++ 2 files changed, 17 insertions(+), 1 deletion(-)