Re: [Xen-staging] [xen-unstable] hvm: Remove access to QEMU monitor inVNC server

[Anthony Liguori <aliguori@us.ibm.com>]

Christian Limpach wrote:
>> QEMU 0.9.0 supports redirecting the monitor to a unix socket and 
>> supports reconnecting to the monitor (so that the banner is 
>> shown each 
>> time).
>>
>> When using these options, you can actually execute monitor 
>> commands from 
>> the command line by doing something like:
>>
>> echo help | socat stdin unix:/path/to/socket
>>
>> With these patches (or by moving qemu-dm up to 0.9.0), 
>> someone could add 
>> an xm monitor command that let you execute commands via xm.
>>
>> That, IMHO, would be the best possible solution.
>>     
>
> I've found that redirecting the monitor using "-monitor pty" works quite
> well since you get access to it using xm console.  That might have been
> broken recently though by the changes to how pty information is written
> to xenstore.
>   

Except if you disconnect from the pty, QEMU is prone to ending up in an 
infinite loop of read() == 0.

> I think it would be better to extend xm console to support additional
> pty's instead of adding a single purpose xm monitor command.
>   

xm console could also be extended to work with domain sockets which do 
not suffer from this problem.

Regards,

Anthony Liguori

>     christian
>