[Intel-gfx] [PATCH v4 09/19] vfio/pci: Accept device fd for hot reset

[Liu, Yi L]

> From: Tian, Kevin <kevin.tian at intel.com>
> Sent: Friday, February 24, 2023 11:57 AM
> 
> > From: Liu, Yi L <yi.l.liu at intel.com>
> > Sent: Friday, February 24, 2023 11:44 AM
> > > > Upon reflection we can probably make it even simpler and just have a
> 0
> > > > length fd array mean to use the iommufd the vfio_device is already
> > > > associated with
> > > >
> > > > And the check for correctness can be simplified to simply see if each
> > > > vfio_device in the dev_set is attached to the same iommufd ctx
> > > > pointer instead of searching the xarray.
> >
> > How about the hot reset info path? We can still keep reporting the
> > current information to userspace. Isn't it?
> 
> No need to change that. It's already reported per device.
> 
> >
> > another tricky question. If user passess iommufd down for reset
> > in the vfio iommufd compatible mode, should we support it as
> > well?
> >
> 
> I don't see why we want to ban it. It does change the result from
> error (vfio container) to success (iommufd vfio-compat) when using
> the container fd/iommufd. But do we actually have a use case
> relying on such error pattern?
>
> On the other hand an user who knows the presence of vfio-compat
> should be allowed to pass iommufd to reset even when it still uses
> the legacy group/container interfaces.

Yes. although I guess no user would do such a strange thing if
no special reason. 😊

Regards,
Yi Liu