Re: [qvm86-devel] qvm86 under amd64 is now working.

[qemu]

On Wed, 27 Jul 2005, Paul Brook wrote:

> On Wednesday 27 July 2005 09:56, address@hidden wrote:
> > I have upated switch.S and qvm86 now compiles and boots under amd64.
> 
> Really? How did you cope with PAE (ie. 64-bit physical memory addresses)?
> The shadow pagetable code definitely doesn't handle that, I'm currently part 
> way through implementing it.

Truth be told, it doesn't.  All of my memory is below 32bits (1gb) which
is probably why we've not seen a problem.  Systems with more memory would
need to be mapped down somehow.  If you have been working on an
implementation which supports PAE then you are far ahead of me!  The diff
and switch.S are available here:

http://www.nsci.us/~ewheeler/qvm86/

The changes I have made allow it to compile without error and use the REX
registers.  The AMD x86-64 Architecture Programmer's Manual was an
excellent help (below).  It only took an hour or two to make the updates
to switch.S and most of the changes were simple replacements such as
:%s/e\([abcd]x\)/r\1/g .  See the block comments around pushq and popq.  
Since %ds,es,fs,gs don't appear to exist on x86_64, I wasn't sure what to
do with them.  To my surprise, it still worked even after blindly
commenting out the blocks.  Perhaps you can offer better insight as to
what this actually affects.

The qvm86.ko module inserts fine and qemu reports that qvm86 is active.  
In addition, w2k appears to boot faster but has the same problem that
kqemu does, thus prompting my interest in qvm86
(http://m2.dad-answers.com/qemu-forum/viewtopic.php?t=123).  Initially I
thought this was a gcc4 issue, but someone else is experiencing the same
issue.  Since both kqemu and qvm86 BSOD at the same place, it may be a
qemu issue more than an accelerator issue.

Your thoughts?

-Eric

The forum thread which prompted me to update switch.S is here: 
  http://m2.dad-answers.com/qemu-forum/viewtopic.php?t=123

AMD Programmer's manual:
http://www.amd.com/us-en/assets/content_type/DownloadableAssets/dwamd_24592.pdf 
 


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