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[Qemu-devel] Re: [PATCH 00/11] AHCI emulation support v9


From: Alexander Graf
Subject: [Qemu-devel] Re: [PATCH 00/11] AHCI emulation support v9
Date: Wed, 15 Dec 2010 00:34:43 +0100

On 14.12.2010, at 17:28, Kevin Wolf wrote:

> Am 14.12.2010 01:34, schrieb Alexander Graf:
>> This patch adds support for AHCI emulation. I have tested and verified it 
>> works
>> in Linux, OpenBSD, Windows Vista and Windows 7. This AHCI emulation supports
>> NCQ, so multiple read or write requests can be outstanding at the same time.
>> 
>> The code is however not fully optimized yet. I'm fairly sure that there are
>> low hanging performance fruits to be found still :). In my simple benchmarks
>> I achieved about 2/3rd of virtio performance.
>> 
>> Also, this AHCI emulation layer does not support legacy mode. So if you're
>> using a disk with this emulation, you do not get it exposed using the legacy
>> IDE interfaces.
>> 
>> Another nitpick is CD-ROM support in Windows. Somehow it doesn't detect a
>> CD-ROM drive attached to AHCI. At least it doesn't list it.
>> 
>> To attach an AHCI disk to your VM, please use
>> 
>>  -drive id=disk,file=...,if=none -device ahci,id=ahci \
>>  -device ide-drive,drive=disk,bus=ahci.0
>> 
>> This patch set is based on work done during the Google Summer of Code. I was
>> mentoring a student, Roland Elek, who wrote most of the AHCI emulation code
>> based on a patch from Chong Qiao. A bunch of other people were also involved,
>> so everybody who I didn't mention - thanks a lot!
>> 
>>  git://repo.or.cz/qemu/ahci.git ahci
> 
> I have applied everything but patch 4 (including patch 12/11) to the
> block branch. Before I can include it in a pull request I need at least
> a new version of patch 3 and you'll probably want to have a new patch 4
> in. There's no need to resend the rest of the patch series.
> 
> For the changes needed please see the comments on the individual patches.

There you go, all new and shiny (actually working) versions of patch 3 and 4 
:). Thanks for pulling this in - let's hope we'll get some happy users with 
this feature!

One thing that might be worth considering is to have preliminary seabios 
support for booting. Gerd does have something in the queue there ;).


Alex





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