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Subject: RE: [RFC 15/20] vfio/pci: Add VFIO_DEVICE_[DE]ATTACH_IOASID
Thread-Topic: [RFC 15/20] vfio/pci: Add VFIO_DEVICE_[DE]ATTACH_IOASID
Thread-Index: AQHXrSGrvqwDmY670Eehf+r4QAc6S6uuy+yAgACk0sA=
Date:   Wed, 22 Sep 2021 03:56:18 +0000
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References: <20210919063848.1476776-1-yi.l.liu@intel.com>
 <20210919063848.1476776-16-yi.l.liu@intel.com>
 <20210921180417.GZ327412@nvidia.com>
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> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Wednesday, September 22, 2021 2:04 AM
>=20
> On Sun, Sep 19, 2021 at 02:38:43PM +0800, Liu Yi L wrote:
> > This patch adds interface for userspace to attach device to specified
> > IOASID.
> >
> > Note:
> > One device can only be attached to one IOASID in this version. This is
> > on par with what vfio provides today. In the future this restriction ca=
n
> > be relaxed when multiple I/O address spaces are supported per device
>=20
> ?? In VFIO the container is the IOS and the container can be shared
> with multiple devices. This needs to start at about the same
> functionality.

a device can be only attached to one container. One container can be
shared by multiple devices.

a device can be only attached to one IOASID. One IOASID can be shared
by multiple devices.

it does start at the same functionality.

>=20
> > +	} else if (cmd =3D=3D VFIO_DEVICE_ATTACH_IOASID) {
>=20
> This should be in the core code, right? There is nothing PCI specific
> here.
>=20

but if you insist on a pci-wrapper attach function, we still need something
here (e.g. with .attach_ioasid() callback)?