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From: Avi Kivity <avi@qumranet.com>
To: Anthony Liguori <aliguori@us.ibm.com>
Cc: kvm-devel@lists.sourceforge.net,
	Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Subject: Re: [ToDo] Real Mode Support
Date: Sun, 10 Feb 2008 13:44:05 +0200	[thread overview]
Message-ID: <47AEE385.7030306@qumranet.com> (raw)
In-Reply-To: <47A9EF21.3050103@us.ibm.com>

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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  parent reply	other threads:[~2008-02-10 11:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-06  7:33 [ToDo] Real Mode Support Guillaume Thouvenin
2008-02-06  8:52 ` Izik Eidus
     [not found]   ` <1202287974.23342.8.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2008-02-06 12:07     ` Guillaume Thouvenin
2008-02-06 12:52       ` Izik Eidus
2008-02-06 23:52       ` Kamble, Nitin A
2008-02-07 18:36         ` Alexey Eremenko
2008-02-06 17:32 ` Anthony Liguori
     [not found]   ` <47A9EF21.3050103-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
2008-02-06 17:47     ` Izik Eidus
2008-02-10 11:44   ` Avi Kivity [this message]
2008-02-11 13:39     ` Guillaume Thouvenin
2008-02-11 14:20       ` Avi Kivity

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