From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC PATCH 00/17] virtual-bus Date: Thu, 02 Apr 2009 09:46:49 +0300 Message-ID: <49D45F59.9030100@redhat.com> References: <20090402030935.GA27836@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , andi@firstfloor.org, ghaskins@novell.com, linux-kernel@vger.kernel.org, agraf@suse.de, pmullaney@novell.com, pmorreale@novell.com, rusty@rustcorp.com.au, netdev@vger.kernel.org, kvm@vger.kernel.org To: Herbert Xu Return-path: Received: from mx2.redhat.com ([66.187.237.31]:53305 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750975AbZDBGrH (ORCPT ); Thu, 2 Apr 2009 02:47:07 -0400 In-Reply-To: <20090402030935.GA27836@gondor.apana.org.au> Sender: kvm-owner@vger.kernel.org List-ID: Herbert Xu wrote: > Anthony Liguori wrote: > >> That said, I don't think we're bound today by the fact that we're in >> userspace. Rather we're bound by the interfaces we have between the >> host kernel and userspace to generate IO. I'd rather fix those >> interfaces than put more stuff in the kernel. >> > > I'm sorry but I totally disagree with that. By having our IO > infrastructure in user-space we've basically given up the main > advantage of kvm, which is that the physical drivers operate in > the same environment as the hypervisor. > I don't understand this. If we had good interfaces, all that userspace would do is translate guest physical addresses to host physical addresses, and translate the guest->host protocol to host API calls. I don't see anything there that benefits from being in the kernel. Can you elaborate? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.