From: Gleb Natapov <gleb@scylladb.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Avi Kivity <avi@scylladb.com>,
Alex Williamson <alex.williamson@redhat.com>,
avi@cloudius-systems.com, corbet@lwn.net,
bruce.richardson@intel.com, linux-kernel@vger.kernel.org,
alexander.duyck@gmail.com, gleb@cloudius-systems.com,
stephen@networkplumber.org, vladz@cloudius-systems.com,
iommu@lists.linux-foundation.org, hjk@hansjkoch.de,
gregkh@linuxfoundation.org
Subject: Re: [RFC PATCH 2/2] vfio: Include no-iommu mode
Date: Sun, 11 Oct 2015 12:23:03 +0300 [thread overview]
Message-ID: <20151011092303.GA19867@scylladb.com> (raw)
In-Reply-To: <20151011091954.GA27451@redhat.com>
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.
next prev parent reply other threads:[~2015-10-11 9:23 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-09 18:40 [RFC PATCH 0/2] VFIO no-iommu Alex Williamson
2015-10-09 18:41 ` [RFC PATCH 1/2] vfio: Move vfio.c vfio_core.c Alex Williamson
2015-10-09 19:21 ` Greg KH
2015-10-09 18:41 ` [RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson
2015-10-11 8:12 ` Avi Kivity
2015-10-11 8:57 ` Michael S. Tsirkin
2015-10-11 9:03 ` Avi Kivity
2015-10-11 9:19 ` Michael S. Tsirkin
2015-10-11 9:23 ` Gleb Natapov [this message]
2015-10-11 21:16 ` Alex Williamson
2015-10-12 15:56 ` Stephen Hemminger
2015-10-12 16:23 ` Alex Williamson
2015-10-12 16:31 ` Avi Kivity
2015-10-12 16:27 ` Michael S. Tsirkin
2015-10-12 17:46 ` Alex Williamson
2015-10-12 18:08 ` Alex Williamson
2015-10-11 17:29 ` [RFC PATCH 0/2] VFIO no-iommu Varun Sethi
2015-10-11 18:23 ` Alex Williamson
2015-10-11 18:28 ` Michael S. Tsirkin
2015-10-11 18:29 ` Michael S. Tsirkin
2015-10-11 19:25 ` Alex Williamson
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