RE: [PATCH v5 10/19] vfio: Add infrastructure for bind_iommufd from userspace

Liu, Yi L
2023-02-28T13:25:05Z

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, February 28, 2023 8:53 PM
>
> On Tue, Feb 28, 2023 at 12:48:23PM +0000, Liu, Yi L wrote:
> > > From: Jason Gunthorpe <jgg@nvidia.com>
> > > Sent: Tuesday, February 28, 2023 8:30 PM
> > >
> > > On Tue, Feb 28, 2023 at 02:35:25AM +0000, Liu, Yi L wrote:
> > >
> > > > > And the commit message is sort of out of sync with the patch, more
> like:
> > > > >
> > > > > vfio: Pass the pt_id as an argument to vfio_iommufd_bind()
> > > > >
> > > > > To support binding the cdev the pt_id must come from userspace
> > > instead
> > > > > of being forced to the compat_ioas_id.
> > > > >
> > > >
> > > > Got it. not only pt_id, also dev_id. 😊
> > >
> > > Maybe dev_id should be read back from the iommufd_device pointer in
> > > the vfio_device. It is trivially stored in that memory already
> >
> > Yes. this somehow gives me a doubt. Why iommufd_device_bind()
> returns
> > both iommufd_device pointer and the id back as id is already stored in the
> > iommufd_device. Is it?
>
> Yes, it was done this way to avoid another API to get the ID, but
> perhaps that is more conveient for vfio anyhow. We could get rid of
> the id return pointer as well

Ok, maybe I can have a small patch to add API like iommufd_device_id()
to get devid, and get rid of the id return pointer as part of this series or
an independent prerequisite patch for this series.

Regards,
Yi Liu