Re: [PATCH] Move irq sharing information to irqchip level.

[Avi Kivity <avi@redhat.com>]

On 08/23/2009 02:56 PM, Gleb Natapov wrote:
>>>> Does msi actually care about the states?  I don't think it does.
>>>>          
>>> That is the point. MSI doesn't care, but we don't know if GSI is MSI or
>>> not.
>>>        
>> So we toggle the bits needlessly.  Just like with edge-triggered interrupts.
>>      
> If we can avoid it why not?
>    

It simplifies the code.  You do it at the kvm_set_irq() entry point 
regardless of whether the interrupt is level-triggered, edge-triggered, 
or msi.  As a bonus, you only do it once (not twice for pic/ioapic 
interrupts).

>> All interrupts connected through one GSI are shared, so why not keep
>> the level information shared as well?
>>
>>      
> If we will keep sharing info at irq routing table level how will we recalculate
> sharing state when irq routing table changes?
>    

Good question.  Move from old table to new table? but that interferes 
with rcu.

Okay, at irqchip level is better after all.

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