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Date: Thu, 11 Mar 2010 15:07:57 +0200
From: Avi Kivity <avi@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH] Inter-VM shared memory PCI device
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To: Arnd Bergmann <arnd@arndb.de>
Cc: Cam Macdonell <cam@cs.ualberta.ca>, qemu-devel@nongnu.org, kvm@vger.kernel.org

On 03/11/2010 02:57 PM, Arnd Bergmann wrote:
> On Thursday 11 March 2010, Avi Kivity wrote:
>    
>>> A totally different option that avoids this whole problem would
>>> be to separate the signalling from the shared memory, making the
>>> PCI shared memory device a trivial device with a single memory BAR,
>>> and using something a higher-level concept like a virtio based
>>> serial line for the actual signalling.
>>>
>>>        
>> That would be much slower.  The current scheme allows for an
>> ioeventfd/irqfd short circuit which allows one guest to interrupt
>> another without involving their qemus at all.
>>      
> Yes, the serial line approach would be much slower, but my point
> was that we can do signaling over "something else", which could
> well be something building on irqfd.
>    

Well, we could, but it seems to make things more complicated?  A card 
with shared memory, and another card with an interrupt interconnect?

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