From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Paul Brook <paul@codesourcery.com>,
qemu-devel@nongnu.org, Andrea Arcangeli <aarcange@redhat.com>,
chrisw@redhat.com, kvm@vger.kernel.org,
Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH 2 of 5] add can_dma/post_dma for direct IO
Date: Mon, 15 Dec 2008 08:23:12 +0200 [thread overview]
Message-ID: <4945F7D0.1070200@redhat.com> (raw)
In-Reply-To: <4945BC63.1080600@codemonkey.ws>
Anthony Liguori wrote:
>>
>> I Wouldn't be surprised if some machines had a large memory mapped IO
>> space. Most of it might not be actively used, but once you start
>> considering 64-bit machines on 32-bit hosts these allocations would
>> become problematic.
>>
>
> At some level, any DMA API would fall apart here. Certain IO
> operations simply cannot be split (such as network send). If you pass
> don't pass a flag to the map function that says you can handle partial
> results, you must cope with map() returning NULL (by dropping the
> packet).
>
... and then you must cope with it. In all non-network dma clients. Or
in the dma api.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2008-12-15 6:25 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-12 18:16 [PATCH 0 of 5] dma api v3 Andrea Arcangeli
2008-12-12 18:16 ` [PATCH 1 of 5] fix cpu_physical_memory len Andrea Arcangeli
2008-12-12 19:06 ` Anthony Liguori
2008-12-12 19:26 ` Andrea Arcangeli
2008-12-12 18:16 ` [PATCH 2 of 5] add can_dma/post_dma for direct IO Andrea Arcangeli
2008-12-12 19:00 ` [Qemu-devel] " 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 ` Anthony Liguori
2008-12-12 19:37 ` Andrea Arcangeli
2008-12-12 20:09 ` Anthony Liguori
2008-12-12 20:25 ` Gerd Hoffmann
2008-12-12 19:39 ` Anthony Liguori
2008-12-13 9:22 ` [Qemu-devel] " 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 [this message]
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 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 ` [Qemu-devel] " 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 ` [PATCH 3 of 5] rename dma.c to isa_dma.c Andrea Arcangeli
2008-12-12 18:16 ` [PATCH 4 of 5] dma api Andrea Arcangeli
2008-12-12 18:55 ` [Qemu-devel] " Blue Swirl
2008-12-12 18:16 ` [PATCH 5 of 5] bdrv_aio_readv/writev Andrea Arcangeli
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