From: Gerd Hoffmann <kraxel@redhat.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: chrisw@redhat.com, avi@redhat.com, qemu-devel@nongnu.org,
kvm@vger.kernel.org
Subject: [Qemu-devel] Re: [PATCH 2 of 5] add can_dma/post_dma for direct IO
Date: Fri, 12 Dec 2008 21:25:58 +0100 [thread overview]
Message-ID: <4942C8D6.5080209@redhat.com> (raw)
In-Reply-To: <20081212193743.GC30537@random.random>
Andrea Arcangeli wrote:
> On Fri, Dec 12, 2008 at 01:15:13PM -0600, Anthony Liguori wrote:
>> 1) You attempt to map a physical address. This effectively is a lock or
>> pin operation.
>
> lock or pin for what? There's nothing to pin or lock here.
Oh, there is in Xen context (i.e. qemu in dom0 handles device emulation
for xen domU guests). You can ask Xen to map the grant (or guest pfn)
here. I think doing so will kill the need for the mapcache patches
xensource carries in the xenified qemu tree.
>> 4) You unmap or unlock that memory region. The virtual address is now no
>> longer valid.
>
> Again not needed.
Likewise useful for Xen.
cheers,
Gerd
next prev parent reply other threads:[~2008-12-12 20:26 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-12 18:16 [Qemu-devel] [PATCH 0 of 5] dma api v3 Andrea Arcangeli
2008-12-12 18:16 ` [Qemu-devel] [PATCH 1 of 5] fix cpu_physical_memory len Andrea Arcangeli
2008-12-12 19:06 ` [Qemu-devel] " Anthony Liguori
2008-12-12 19:26 ` Andrea Arcangeli
2008-12-12 18:16 ` [Qemu-devel] [PATCH 2 of 5] add can_dma/post_dma for direct IO Andrea Arcangeli
2008-12-12 19:00 ` Blue Swirl
2008-12-12 19:18 ` Anthony Liguori
2008-12-12 20:05 ` Blue Swirl
2008-12-12 20:10 ` Anthony Liguori
2008-12-12 19:15 ` [Qemu-devel] " Anthony Liguori
2008-12-12 19:37 ` Andrea Arcangeli
2008-12-12 20:09 ` Anthony Liguori
2008-12-12 20:25 ` Gerd Hoffmann [this message]
2008-12-12 19:39 ` Anthony Liguori
2008-12-13 9:22 ` Avi Kivity
2008-12-13 16:45 ` Anthony Liguori
2008-12-13 19:48 ` Avi Kivity
2008-12-13 21:07 ` Anthony Liguori
2008-12-14 6:03 ` Avi Kivity
2008-12-14 19:10 ` Anthony Liguori
2008-12-14 19:49 ` Avi Kivity
2008-12-14 23:08 ` Anthony Liguori
2008-12-15 0:57 ` Paul Brook
2008-12-15 2:09 ` Anthony Liguori
2008-12-15 6:23 ` Avi Kivity
2008-12-15 18:35 ` Blue Swirl
2008-12-15 22:06 ` Anthony Liguori
2008-12-16 9:41 ` Avi Kivity
2008-12-16 16:55 ` Blue Swirl
2008-12-16 17:09 ` Avi Kivity
2008-12-16 17:48 ` Anthony Liguori
2008-12-16 18:11 ` Blue Swirl
2008-12-16 15:57 ` Blue Swirl
2008-12-16 16:29 ` Paul Brook
2008-12-16 16:35 ` Blue Swirl
2008-12-14 17:30 ` Jamie Lokier
2008-12-13 14:39 ` Andrea Arcangeli
2008-12-13 16:46 ` Anthony Liguori
2008-12-13 16:53 ` Andrea Arcangeli
2008-12-13 17:54 ` Andreas Färber
2008-12-13 21:11 ` Anthony Liguori
2008-12-14 16:47 ` Andrea Arcangeli
2008-12-14 17:01 ` Avi Kivity
2008-12-14 17:15 ` Andrea Arcangeli
2008-12-14 19:59 ` Avi Kivity
2008-12-22 16:44 ` Ian Jackson
2008-12-22 19:44 ` Avi Kivity
2008-12-23 0:03 ` Thiemo Seufer
2008-12-23 1:02 ` Andrea Arcangeli
2008-12-23 17:31 ` Avi Kivity
2008-12-22 19:46 ` Avi Kivity
2009-01-05 10:27 ` Gerd Hoffmann
2008-12-13 22:47 ` Anthony Liguori
2008-12-14 6:07 ` Avi Kivity
2008-12-12 18:16 ` [Qemu-devel] [PATCH 3 of 5] rename dma.c to isa_dma.c Andrea Arcangeli
2008-12-12 18:16 ` [Qemu-devel] [PATCH 4 of 5] dma api Andrea Arcangeli
2008-12-12 18:55 ` Blue Swirl
2008-12-12 18:16 ` [Qemu-devel] [PATCH 5 of 5] bdrv_aio_readv/writev Andrea Arcangeli
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