From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] [PATCH] Inter-VM shared memory PCI device Date: Mon, 08 Mar 2010 11:52:13 +0200 Message-ID: <4B94C8CD.2030808@redhat.com> References: <1267833161-25267-1-git-send-email-cam@cs.ualberta.ca> <1267833161-25267-2-git-send-email-cam@cs.ualberta.ca> <201003072254.00040.paul@codesourcery.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, Cam Macdonell , kvm@vger.kernel.org To: Paul Brook Return-path: Received: from mx1.redhat.com ([209.132.183.28]:31570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753334Ab0CHJwZ (ORCPT ); Mon, 8 Mar 2010 04:52:25 -0500 In-Reply-To: <201003072254.00040.paul@codesourcery.com> Sender: kvm-owner@vger.kernel.org List-ID: On 03/08/2010 12:53 AM, Paul Brook wrote: >> Support an inter-vm shared memory device that maps a shared-memory object >> as a PCI device in the guest. This patch also supports interrupts between >> guest by communicating over a unix domain socket. This patch applies to >> the qemu-kvm repository. >> > No. All new devices should be fully qdev based. > > I suspect you've also ignored a load of coherency issues, especially when not > using KVM. As soon as you have shared memory in more than one host > thread/process you have to worry about memory barriers. > Shouldn't it be sufficient to require the guest to issue barriers (and to ensure tcg honours the barriers, if someone wants this with tcg)?. -- error compiling committee.c: too many arguments to function