Re: [PATCH] interrupt preemption support

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

>>> On Mon, Mar 19, 2007 at 10:03 AM, in message <45FE9827.5030200-atKUWr5tajBWk0Htik3J/w@public.gmane.org>,
Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> wrote: 
> Avi Kivity wrote:
>> Gregory Haskins wrote:
>>> Hi Avi,
>>>   You make good points.  I will convert to a nest lock design and 
>>> resubmit.   Should I use two mutexes, or a mutex and spinlock?
>>>
>>> Also, do you have any suggestions on the signum I should use to IPI 
>>> the running guest?  Should I use one of the normal signals (SIGUSR) 
>>> or should I start a block of defined signals in the RT range (>32)?
>>>   
>>
>> For a short term solution, where the apic is in userspace, we can just 
>> say ipi == signal, and not require any locking.  Qemu will catch the 
>> signal and call the appropriate apic function.  The signal number 
>> should be set from userspace.
>>
> 
> Note that as long as the apic code is in userspace, the sending side is 
> also in userspace, so all the IPI related stuff doesn't touch the kernel.


I see.  So really the entire approach I took (against the kernel code) is wrong, and I should focus on the QEMU side?

-Greg

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