Re: [RFC PATCH 2/2] vfio: Include no-iommu mode

From	Gleb Natapov <gleb@scylladb.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 2/2] vfio: Include no-iommu mode
Date	2015-10-11 11:30 +0200
Message-ID	<qil74-49b-11@gated-at.bofh.it> (permalink)
References	(1 earlier) <qhKTU-231-19@gated-at.bofh.it> <qik1k-2Ay-15@gated-at.bofh.it> <qikE1-3lP-5@gated-at.bofh.it> <qikNH-3Mq-5@gated-at.bofh.it> <qil74-49b-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Sun, Oct 11, 2015 at 12:19:54PM +0300, Michael S. Tsirkin wrote:
> > But since you must pass the same value to open(), you already know that
> > you're using noiommu.
> > 
> > >VFIO_IOMMU_MAP_DMA, VFIO_IOMMU_ENABLE and VFIO_IOMMU_DISABLE
> > >will probably also fail ...
> > >
> > 
> > Don't you have to call MAP_DMA to pin the memory?
> 
> Well check it out - the patch in question doesn't implement this ioctl.
> In fact it doesn't implement anything except CHECK_EXTENSION.
> 
> And this makes sense to me: MAP_DMA
> maps a virtual address to io address, and that doesn't
> work for the dummy iommu.
> 
> You can pin memory using many other ways, including
> mlock and hugetlbfs.
> 
mlock() does not pin memory.

--
			Gleb.
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Thread

[RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson <alex.williamson@redhat.com> - 2015-10-09 20:50 +0200
  Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Avi Kivity <avi@scylladb.com> - 2015-10-11 10:20 +0200
    Re: [RFC PATCH 2/2] vfio: Include no-iommu mode "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-11 11:00 +0200
      Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Avi Kivity <avi@scylladb.com> - 2015-10-11 11:10 +0200
        Re: [RFC PATCH 2/2] vfio: Include no-iommu mode "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-11 11:30 +0200
          Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Gleb Natapov <gleb@scylladb.com> - 2015-10-11 11:30 +0200
    Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson <alex.williamson@redhat.com> - 2015-10-11 23:20 +0200
  Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Stephen Hemminger <stephen@networkplumber.org> - 2015-10-12 18:00 +0200
    Re: [RFC PATCH 2/2] vfio: Include no-iommu mode "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-12 18:30 +0200
      Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson <alex.williamson@redhat.com> - 2015-10-12 19:50 +0200
        Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson <alex.williamson@redhat.com> - 2015-10-12 20:10 +0200
    Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson <alex.williamson@redhat.com> - 2015-10-12 18:30 +0200
      Re: [RFC PATCH 2/2] vfio: Include no-iommu mode Avi Kivity <avi@scylladb.com> - 2015-10-12 18:40 +0200

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