[Qemu-devel] [PATCH] Virtual PC image support

[Alex Beregszaszi]

Hi,

Attached is a patch for read only support of such images. I tested this
with an Ubuntu 4.10 and Windows 2000 install.

Some technical notes:

* looks like VPC creates always 16 GB images, and I didnt found a way to
change this. Also imho it will grow above 16gigs, as it has a duplicate
sparse header at the end.

* it has the usual two-level bitmaps, like an offset table first and 512
entry bitmaps afterwards. The l2 bitmaps are a bit meaningless for
read-only support as it looks like that if a new bitmap gets used, all
the relevant sectors are set to zero, but the bitmap remains the
default. So for write support we definitely would like to look at the
individual bits, but for read support it works out safe not taking care
of those bits. They are a bit even munged, like stored as 32bit
big-endian integers.

* this is not that slow as I mentioned earlier, I did booted from the
images

Note: the "cache" stuff is disabled by reased, as it is not needed

-- 
Alex Beregszaszi                        e-mail: address@hidden
Free Software Network                   cell: +36 70 3144424

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block-vpc.c
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