From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: virtio & hypercall interface? Date: Sat, 15 Sep 2007 12:31:53 -0500 Message-ID: <46EC1709.2080803@us.ibm.com> References: <1189664514.32322.14.camel@localhost.localdomain> <64F9B87B6B770947A9F8391472E032160DA17EF2@ehost011-8.exch011.intermedia.net> <46E9A17D.5040205@us.ibm.com> <46EABAD0.40300@qumranet.com> <46EB0BD8.6040000@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , Avi Kivity To: dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org Return-path: In-Reply-To: <46EB0BD8.6040000-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dor Laor wrote: > Avi Kivity wrote: >> Anthony Liguori wrote: >> >>> Dor Laor wrote: >>> >>>>> Hi all, >>>>> >>>>> I've finally started looking at Dor's git tree, and it struck me >>>>> >>>> that >>>> >>>>> it conflicts with Anthony's hypercall patches. FWIW I like Anthony's >>>>> patching thing, and don't really care about arg order. It'd be >>>>> nice if >>>>> we could pull in the same direction tho 8) >>>>> >>>>> Thanks, >>>>> Rusty. >>>>> >>>> Good news you're looking at my tree, since the forum I didn't do much >>>> since I had to catch up some gazlion other tasks, never the less >>>> starting on Sunday I'm back again. >>>> >>>> Actually, I wanted to rebase my hypercalls over Anhtony's too (except >>>> for allowing userspace handling). >>>> >>> I thought we discussed just providing a signaling message to >>> userspace for virtio? It's not strictly necessary to expose >>> hypercalls to userspace in order to implement a virtio backend in >>> userspace. >>> >>> >> >> Yes, that's what I'd like to see too. Signal a channel. >> >> > First, I though that this > http://www.mail-archive.com/kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org/msg06230.html > was your latest opinion. > Second, regardless of the channel signal notification, there are still > real necessities for userspace hypercall handling: > 1. For virtio drivers there is also registration hypercall for passing > the shared memory pfns. > Sure there are other possibilities, but why limit ourselves? Can you elaborate here? Using a PCI discover mechanism, you've got your memory already. Not point in reinventing PCI with hypercalls. > > 2. For other purposes such as a balloon driver, a deflate/inflate > hypercalls are needed. > Although for x86 mmio/pio can be used but this is not compatible > with other architectures. Isn't a balloon driver just another virtio device? Rather, it might be interesting to build a simple RPC mechanism on top of virtio and do things like balloon on top of that. Regards, Anthony Liguori > Regards & thanks for the patch resend, > Dor ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/