[ipxe-devel] iPXE with Virtualbox

[Pete I. Eby]

Hi Matthew,

I'm glad you narrowed this down - I've been meaning to do the git bisect
since that original thread, and just never got back to it. Thanks for
doing this.

I'd love to see this resolved as using iPXE with VirtualBox would be
extremely handy, as otherwise one is left using earlier gPXE versions.

Cheers,
Pete

On Sat, 2011-01-22 at 14:35 -0500, Matthew Walster wrote:
> Apologies for not replying to the previous (small) thread regarding
> this topic, I wasn't a subscriber back then.
> 
> iPXE doesn't work in Virtualbox, and it was suggested that someone run
> through the "git bisect" procedure to find the commit. I've done so,
> and git reports the following commit as the likely culprit:
> 
> 
> 6c35a525da16c6147600cd8613a9b60bb793b934 is the first bad commit
> commit 6c35a525da16c6147600cd8613a9b60bb793b934
> Author: Michael Brown <mcb30 at ipxe.org>
> Date:   Mon Apr 19 22:22:11 2010 +0100
> 
>     [prefix] Use flat real mode for access to high memory
> 
>     Use flat real mode rather than 16-bit protected mode for access to
>     high memory during installation.  This simplifies the code by reducing
>     the number of CPU modes we need to think about, and also increases the
>     amount of code in common between the normal and (somewhat
>     hypothetical) KEEP_IT_REAL methods of operation.
> 
>     Signed-off-by: Michael Brown <mcb30 at ipxe.org>
> 
> :040000 040000 b4009d2b7e45222d34db4f466b89520c80d4d707
> 2a79c6844ccd8f7554636619abf65d67f8966ba2 M	src
> 
> 
> I find it quite amusing that the preceding commit says:
> 
> 
>     This change is unlikely to break anything, since any code that might
>     potentially access beyond 64kB must use addr32 prefixes to do so; if
>     this is the case then it is almost certainly code written to expect
>     flat real mode anyway.
> 
> 
> Oh well ;)
> 
> I'm not familiar enough with low-level coding to test further, but if
> someone would like to give me further pointers I'd be glad to assist.
> 
> Matthew Walster
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