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From:   "Tian, Kevin" <kevin.tian@intel.com>
To:     Jason Gunthorpe <jgg@nvidia.com>,
        David Gibson <david@gibson.dropbear.id.au>
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        Jonathan Corbet <corbet@lwn.net>,
        "Raj, Ashok" <ashok.raj@intel.com>,
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Subject: RE: [RFC] /dev/ioasid uAPI proposal
Thread-Topic: [RFC] /dev/ioasid uAPI proposal
Thread-Index: AddSzQ970oLnVHLeQca/ysPD8zMJZwEqZK+AABc0DAAAG3kNAAANRVGAACT84AA=
Date:   Fri, 4 Jun 2021 06:27:17 +0000
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> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Thursday, June 3, 2021 8:46 PM
>=20
> On Thu, Jun 03, 2021 at 04:26:08PM +1000, David Gibson wrote:
>=20
> > > There are global properties in the /dev/iommu FD, like what devices
> > > are part of it, that are important for group security operations. Thi=
s
> > > becomes confused if it is split to many FDs.
> >
> > I'm still not seeing those.  I'm really not seeing any well-defined
> > meaning to devices being attached to the fd, but not to a particular
> > IOAS.
>=20
> Kevin can you add a section on how group security would have to work
> to the RFC? This is the idea you can't attach a device to an IOASID
> unless all devices in the IOMMU group are joined to the /dev/iommu FD.
>=20
> The basic statement is that userspace must present the entire group
> membership to /dev/iommu to prove that it has the security right to
> manipulate their DMA translation.
>=20
> It is the device centric analog to what the group FD is doing for
> security.
>=20

Yes, will do.

Thanks
Kevin