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Date: Fri, 22 Jan 2010 12:05:19 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 08/11] QMP: Asynchronous messages
	enable/disable support
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To: Luiz Capitulino <lcapitulino@redhat.com>
Cc: aliguori@us.ibm.com, avi@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com

On 01/21/2010 03:09 PM, Luiz Capitulino wrote:
> This commit disables asynchronous messages by default and
> introduces two new QMP commands: async_msg_enable and
> async_msg_disable.
>
> Each QMP Monitor has its own set of asynchronous messages,
> so for example, if QEMU is run with two QMP Monitors async
> messages setup in one of them doesn't affect the other.
>
> To implement this design a bitmap is introduced to the
> Monitor struct, each async message is represented by one bit.
>
> Signed-off-by: Luiz Capitulino<lcapitulino@redhat.com>
>    

Ah, I see I was a little confused.

I'd suggest making async message masking an independent mechanism.  
Capabilities should strictly deal with protocol changes, not feature 
details.

For instance, protocol timestamps are something would reasonable 
considered a capability.  Extended data types would be a capability.

Another way to look at it, is that if you're writing a client library, 
the capability negotiation should be entirely invisible to the end API user.

Regards,

Anthony Liguori