From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@qumranet.com>
Subject: Re: [ToDo] Real Mode Support
Date: Sun, 10 Feb 2008 13:44:05 +0200
Message-ID: <47AEE385.7030306@qumranet.com>
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Cc: kvm-devel@lists.sourceforge.net,
	Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
To: Anthony Liguori <aliguori@us.ibm.com>
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Anthony Liguori wrote:
> So what we would like to do, is instead of setting up vm86 mode for the 
> guest to execute real mode, use x86_emulate() to just emulate the code.  
> This means that we wouldn't be using the "vmlaunch" instruction when in 
> real mode and instead would be doing an x86_emulate() loop.
>   

As using the emulator is likely to be slower than VT, we can call the 
emulator only if we are in a "VT unfriendly" state, so the code might 
look like

    if (vmx->rmode.active && big_real_mode(vmx))
          ...

In addition, there are some protected-mode states that VT can't handle 
(cs.rpl != ss.rpl IIRC) so we can emulate those cases as well.

To improve speed, we may want to emulate >1 instruction per iteration.

-- 
error compiling committee.c: too many arguments to function


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