Re: [Qemu-devel] [PATCH] -machine vmport=off: Allow disabling of VMWare ioport emulation

[Slutz, Donald Christopher]

What is happening with this patch?  I would like to use this code.

   -Don Slutz

________________________________________
From: address@hidden address@hidden on behalf of Gerd Hoffmann address@hidden
Sent: Tuesday, May 20, 2014 6:10 AM
To: Richard W.M. Jones
Cc: address@hidden; address@hidden; address@hidden; Dr. David Alan Gilbert; 
address@hidden; Anthony PERARD
Subject: Re: [Qemu-devel] [PATCH] -machine vmport=off: Allow disabling of 
VMWare ioport emulation

  Hi,

> It was disabled in this patch.  The commit message is saying that
> vmport cannot work in Xen, but I'm not exactly clear why.
>
>   commit 1611977c3d8fdbdac6090cbd1f5555cee4aed6d9
>   Author: Anthony PERARD <address@hidden>
>   Date:   Tue May 3 17:06:54 2011 +0100
>
>     pc, Disable vmport initialisation with Xen.
>
>     This is because there is not synchronisation of the vcpu register
>     between Xen and QEMU, so vmport can't work properly.

Ah, ok.  The backdoor has side effects (writing the port does modify
vcpu registers).  That is the bit which is problematic for xen.  Scratch
the idea then.

Original patch is fine.

Reviewed-by: Gerd Hoffmann <address@hidden>

cheers,
  Gerd