From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [GIT PULL] AlacrityVM guest drivers for 2.6.33 Date: Sun, 27 Dec 2009 11:33:33 +0200 Message-ID: <4B3729ED.50006@redhat.com> References: <4B1D4F29.8020309@gmail.com> <87637zdy9g.fsf@basil.nowhere.org> <4B30E654.40702@codemonkey.ws> <200912221701.56840.bzolnier@gmail.com> <4B30F214.80206@codemonkey.ws> <20091223065129.GA19600@elte.hu> <4B3248F9.5030504@gmail.com> <4B327F3A.9020101@redhat.com> <4B328535.5040105@redhat.com> <4B33361E.3000605@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Ingo Molnar , Anthony Liguori , Bartlomiej Zolnierkiewicz , Andi Kleen , kvm@vger.kernel.org, Andrew Morton , torvalds@linux-foundation.org, "linux-kernel@vger.kernel.org" , netdev@vger.kernel.org, "alacrityvm-devel@lists.sourceforge.net" To: Gregory Haskins Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60970 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750872AbZL0JeT (ORCPT ); Sun, 27 Dec 2009 04:34:19 -0500 In-Reply-To: <4B33361E.3000605@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 12/24/2009 11:36 AM, Gregory Haskins wrote: >> As a twist on this, the VMware paravirt driver interface is so >> hardware-like that they're getting hardware vendors to supply cards that >> implement it. Try that with a pure software approach. >> > Any hardware engineer (myself included) will tell you that, generally > speaking, what you can do in hardware you can do in software (think of > what QEMU does today, for instance). It's purely a cost/performance > tradeoff. > > I can at least tell you that is true of vbus. Anything on the vbus side > would be equally eligible for a hardware implementation, though there is > not reason to do this today since we have equivalent functionality in > baremetal already. There's a huge difference in the probability of vmware getting cards to their spec, or x86 vendors improving interrupt delivery to guests, compared to vbus being implemented in hardware. > The only motiviation is if you wanted to preserve > ABI etc, which is what vmware is presumably after. However, I am not > advocating this as necessary at this juncture. > Maybe AlacrityVM users don't care about compatibility, but my users do. -- error compiling committee.c: too many arguments to function