Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1258033

Re: [PATCH v3 0/3] virtio DMA API core stuff

From David Woodhouse <dwmw2@infradead.org>
Newsgroups linux.kernel
Subject Re: [PATCH v3 0/3] virtio DMA API core stuff
Date 2015-10-28 14:40 +0100
Message-ID <qoz7k-3cS-9@gated-at.bofh.it> (permalink)
References <qosyS-7ut-7@gated-at.bofh.it> <qotbz-7YX-7@gated-at.bofh.it> <qotEC-89q-1@gated-at.bofh.it> <qou7E-6S-9@gated-at.bofh.it> <qoxfc-21J-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On Wed, 2015-10-28 at 13:35 +0200, Michael S. Tsirkin wrote:
> E.g. on intel x86, there's an option iommu=pt which does the 1:1
> thing for devices when used by kernel, but enables
> the iommu if used by userspace/VMs.

That's none of your business.

You call the DMA API when you do DMA. That's all there is to it.

If the IOMMU happens to be in passthrough mode, or your device happens
to not to be routed through an IOMMU today, then I/O virtual address
you get back from the DMA API will look a *lot* like the physical
address you asked the DMA to map. You might think there's no IOMMU. We
couldn't possibly comment.

Use the DMA API. Always. Let the platform worry about whether it
actually needs to *do* anything or not.

-- 
dwmw2

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v3 0/3] virtio DMA API core stuff Andy Lutomirski <luto@kernel.org> - 2015-10-28 07:40 +0100
  [PATCH v3 2/3] virtio_ring: Support DMA APIs Andy Lutomirski <luto@kernel.org> - 2015-10-28 07:50 +0100
  [PATCH v3 3/3] virtio_pci: Use the DMA API Andy Lutomirski <luto@kernel.org> - 2015-10-28 07:50 +0100
  [PATCH v3 1/3] virtio_net: Stop doing DMA from the stack Andy Lutomirski <luto@kernel.org> - 2015-10-28 07:50 +0100
    Re: [PATCH v3 1/3] virtio_net: Stop doing DMA from the stack "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 08:10 +0100
  Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-28 08:00 +0100
    Re: [PATCH v3 0/3] virtio DMA API core stuff Andy Lutomirski <luto@amacapital.net> - 2015-10-28 08:20 +0100
  Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 08:20 +0100
    Re: [PATCH v3 0/3] virtio DMA API core stuff Christian Borntraeger <borntraeger@de.ibm.com> - 2015-10-28 08:50 +0100
      Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-28 09:20 +0100
        Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 12:40 +0100
          Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-28 14:40 +0100
            Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 15:10 +0100
              Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-28 15:20 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 15:30 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-28 15:40 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 17:20 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff Andy Lutomirski <luto@amacapital.net> - 2015-10-29 00:00 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-29 10:10 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-29 17:20 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff Joerg Roedel <jroedel@suse.de> - 2015-10-30 16:20 +0100
                Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-30 18:00 +0100
      Re: [PATCH v3 0/3] virtio DMA API core stuff Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2015-10-28 09:40 +0100
        Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 12:30 +0100
          Re: [PATCH v3 0/3] virtio DMA API core stuff David Woodhouse <dwmw2@infradead.org> - 2015-10-28 14:40 +0100
            Re: [PATCH v3 0/3] virtio DMA API core stuff "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-28 15:10 +0100

csiph-web