Re: [PATCH 3/4] KVM: Adds ability to preempt an executing VCPU

["Gregory Haskins" <ghaskins-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org>]

>>> On Tue, May 8, 2007 at  4:26 AM, in message <4640341E.6090905-atKUWr5tajBWk0Htik3J/w@public.gmane.org>,
Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> wrote: 
> Gregory Haskins wrote:
>>   
>>> Hopefully not by setting the 
>>> signal number, bit by making the vcpu fd writable (userspace can attach 
>>> a signal to the fd if it wishes).
>>>     
>>
>> Can you provide an example of what you would like here?  I am not quite sure 
> what you mean by making the fd writable.
>>   
> 
> Making it respond to poll(2) as a writable fd.
> 
> See http://lwn.net/Articles/226252/ for an example.  It makes the fd 
> readable instead of writable, but it's the same mechanism.
> 
> The larger picture is that fds and the poll() family are the closest 
> thing Linux has to a generic event framework.  If the patchset in the 
> article above is accepted, fds _will_ be the generic event framework.  
> If something else is accepted, we'll just switch to that.
> 
> Qemu currently depends on signals, but you can have a writable fd 
> generate a signal, and the mechanism for that is optional and 
> configurable from userspace, which is what we want anyway.


Thanks for the link!  I will take a look and add this for my next drop.

-Greg

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