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From:   "Tian, Kevin" <kevin.tian@intel.com>
To:     Alex Williamson <alex.williamson@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>
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        Kirti Wankhede <kwankhede@nvidia.com>,
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Subject: RE: [RFC] /dev/ioasid uAPI proposal
Thread-Topic: [RFC] /dev/ioasid uAPI proposal
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Date:   Fri, 4 Jun 2021 09:19:50 +0000
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> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Friday, June 4, 2021 4:42 AM
>=20
> > 'qemu --allow-no-snoop' makes more sense to me
>=20
> I'd be tempted to attach it to the -device vfio-pci option, it's
> specific drivers for specific devices that are going to want this and
> those devices may not be permanently attached to the VM.  But I see in
> the other thread you're trying to optimize IOMMU page table sharing.
>=20
> There's a usability question in either case though and I'm not sure how
> to get around it other than QEMU or the kernel knowing a list of
> devices (explicit IDs or vendor+class) to select per device defaults.
>=20

"-device vfio-pci" is a per-device option, which implies that the
no-snoop choice is given to the admin then no need to maintain=20
a fixed device list in Qemu?

Thanks
Kevin