From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH v2] Driver for Inter-VM shared memory device for KVM supporting interrupts.
Date: Wed, 20 May 2009 12:28:38 +0930
Message-ID: <200905201228.38718.rusty@rustcorp.com.au>
References: <1241713567-17256-1-git-send-email-cam@cs.ualberta.ca> <4A127776.9030400@redhat.com> <4A12E37C.700@cs.ualberta.ca>
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Cc: Avi Kivity <avi@redhat.com>,
	Christian =?utf-8?q?Borntr=C3=A4ger?= <borntraeger@de.ibm.com>,
	kvm@vger.kernel.org,
	Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
To: Cam Macdonell <cam@cs.ualberta.ca>
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On Wed, 20 May 2009 02:21:08 am Cam Macdonell wrote:
> Avi Kivity wrote:
> > Christian Borntr=C3=A4ger wrote:
> >>> To summarize, Anthony thinks it should use virtio, while I believ=
e
> >>> virtio is useful for exporting guest memory, not for importing ho=
st
> >>> memory.

Yes, precisely.

But what's it *for*, this shared memory?  Implementing shared memory is=
=20
trivial.  Using it is harder.  For example, inter-guest networking: you=
'd have=20
to copy packets in and out, making it slow as well as losing abstractio=
n.

The only interesting idea I can think of is exposing it to userspace, a=
nd=20
having that run some protocol across it for fast app <-> app comms.  Bu=
t if=20
that's your plan, you still have a lot of code the write!

So I guess I'm missing the big picture here?

Thanks,
Rusty.