Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api

From	Paolo Bonzini <pbonzini@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api
Date	2016-05-09 13:10 +0200
Message-ID	<rwRey-4k2-9@gated-at.bofh.it> (permalink)
References	(6 earlier) <rsCe7-5LS-25@gated-at.bofh.it> <rsDaa-6Ba-15@gated-at.bofh.it> <rsVgK-4Ob-25@gated-at.bofh.it> <rsVTt-5A5-35@gated-at.bofh.it> <rsWcO-5NB-21@gated-at.bofh.it>
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On 28/04/2016 17:37, Michael S. Tsirkin wrote:
> > All the internally-emulated devices *can* be either translated or
> > untranslated. That's just a matter of software. Surely, you currently
> > *can't* have translated assigned devices (until someone implements the
> > whole VT-d page table shadowing or whatever), so you'll be barred from
> > assigning a device to a slot which *previously* had an untranslated
> > device. But so what? Put it in a different slot instead.
> 
> Unfortunately people got used to be able to put any device
> in any slot, and built external tools around that ability.
> It's rather painful to break this assumption.

Once you move to PCIe, a lot of things become more complicated.  This is
just one of them; instead of needing half a dozen PCI bridges, you'll
need half a dozen plus one.

Paolo

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Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api "Michael S. Tsirkin" <mst@redhat.com> - 2016-04-28 16:40 +0200
  Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api David Woodhouse <dwmw2@infradead.org> - 2016-04-28 17:20 +0200
    Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api "Michael S. Tsirkin" <mst@redhat.com> - 2016-04-28 17:40 +0200
      Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api David Woodhouse <dwmw2@infradead.org> - 2016-04-28 17:50 +0200
        Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api "Michael S. Tsirkin" <mst@redhat.com> - 2016-05-01 12:40 +0200
      Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api Paolo Bonzini <pbonzini@redhat.com> - 2016-05-09 13:10 +0200

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