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

[Slutz, Donald Christopher]

On 09/25/14 11:07, Dr. David Alan Gilbert wrote:
> * Slutz, Donald Christopher (address@hidden) wrote:
>> What is happening with this patch?  I would like to use this code.
> I need to rework it for the new machine types code; but it was pretty
> low down my list of priorities; but I can try and get a minute for it
> again.

Ok, I did not see any mail about this.  If I am reading this right you mean
like I did in

commit c87b1520726f7ae1e698a41f07043d1b539ac88c

Do you want me to attempt to "port" this patch this way?

     -Don Slutz

> Dave
>
>>     -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
>>
>>
>>
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK