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From: Kevin Wolf <kwolf@redhat.com>
To: Mathias Krause <mathias.krause@secunet.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] CMOS file support
Date: Fri, 17 Sep 2010 12:44:39 +0200	[thread overview]
Message-ID: <4C934697.70102@redhat.com> (raw)
In-Reply-To: <4C930DED.5050601@secunet.com>

Hi Mathias,

Am 17.09.2010 08:42, schrieb Mathias Krause:
>> Using QEMU's block devices instead of a simple file would be
>> more consistent with the rest of QEMU and allow reading the
>> CMOS data not only from a file but also from an URL or other
>> sources.
> 
> Thanks for the hint. Since this is my first contribution to the project
> I'm not that familiar with the code. Looking at other places, e.g. how
> the -kernel option gets handled, I just see FILE everywhere. Can you
> give me some pointers how to use this interface?

Have a look at block.h which contains the prototypes for the public
block layer interface.

Basically, you need to create a BlockDriverState with bdrv_new() and
then open it with bdrv_open(). You'll want to specify the raw block
driver for opening the image, you get it with bdrv_find_format("raw").
bdrv_pread/pwrite are the right functions to access the file with byte
granularity (other functions work on 512 byte sectors). bdrv_delete
frees the the BlockDriverState when you're done.

HTH,
Kevin

  reply	other threads:[~2010-09-17 10:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-16 13:58 [Qemu-devel] [PATCH] CMOS file support Mathias Krause
2010-09-16 16:49 ` Stefan Weil
2010-09-17  6:42   ` Mathias Krause
2010-09-17 10:44     ` Kevin Wolf [this message]
2010-09-17 11:28       ` Mathias Krause
2010-09-24 12:40         ` Markus Armbruster
2010-09-17 10:58     ` Stefan Weil
2010-09-17 11:16       ` Mathias Krause
2010-09-16 17:20 ` Anthony Liguori
2010-09-17  6:50   ` Mathias Krause
2010-09-17 13:27     ` Anthony Liguori
2010-09-22 19:43       ` Mathias Krause
2010-09-23 12:12         ` [Qemu-devel] " Paolo Bonzini
2010-09-24 12:47         ` [Qemu-devel] " Markus Armbruster
2010-09-26 20:44           ` Mathias Krause
2010-10-11 13:25             ` Markus Armbruster
2010-09-24 12:42   ` Markus Armbruster

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