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

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

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.

-- 
error compiling committee.c: too many arguments to function


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