Re: [PATCH v2 07/11] vfio-iommufd: Support iommufd for physical VFIO devices

[Jason Gunthorpe]

On Fri, Nov 11, 2022 at 12:12:36PM +0800, Yi Liu wrote:

> > +int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
> > +{
> > +   u32 ioas_id;
> > +   u32 device_id;
> > +   int ret;
> > +
> > +   lockdep_assert_held(&vdev->dev_set->lock);
> > +
> > +   /*
> > +    * 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;
> > +
> > +   ret = vdev->ops->bind_iommufd(vdev, ictx, &device_id);
> > +   if (ret)
> > +           return ret;
> > +
> > +   ret = iommufd_vfio_compat_ioas_id(ictx, &ioas_id);
> > +   if (ret)
> > +           goto err_unbind;
> > +   ret = vdev->ops->attach_ioas(vdev, &ioas_id);
> > +   if (ret)
> > +           goto err_unbind;
> > +   vdev->iommufd_attached = true;
> 
> it's better to set this bool in vfio_iommufd_physical_attach_ioas() as
> the emulated devices uses iommufd_access instead. is it? or you mean this
> flag to cover both cases?

Yes, that is probably clearer:

@@ -50,7 +50,6 @@ int vfio_iommufd_bind(struct vfio_device *vdev, struct 
iommufd_ctx *ictx)
        ret = vdev->ops->attach_ioas(vdev, &ioas_id);
        if (ret)
                goto err_unbind;
-       vdev->iommufd_attached = true;
 
        /*
         * The legacy path has no way to return the device id or the selected
@@ -110,10 +109,15 @@ EXPORT_SYMBOL_GPL(vfio_iommufd_physical_unbind);
 int vfio_iommufd_physical_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
 {
        unsigned int flags = 0;
+       int rc;
 
        if (vfio_allow_unsafe_interrupts)
                flags |= IOMMUFD_ATTACH_FLAGS_ALLOW_UNSAFE_INTERRUPT;
-       return iommufd_device_attach(vdev->iommufd_device, pt_id, flags);
+       rc = iommufd_device_attach(vdev->iommufd_device, pt_id, flags);
+       if (rc)
+               return rc;
+       vdev->iommufd_attached = true;
+       return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_physical_attach_ioas);
 
Thanks,
Jason