From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752858AbbCWOyP (ORCPT ); Mon, 23 Mar 2015 10:54:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52147 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752144AbbCWOyN (ORCPT ); Mon, 23 Mar 2015 10:54:13 -0400 Date: Mon, 23 Mar 2015 15:54:01 +0100 From: "Michael S. Tsirkin" To: Gerd Hoffmann Cc: virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, Rusty Russell , open list , "open list:ABI/API" Subject: Re: [PATCH 1/1] Add virtio-input driver. Message-ID: <20150323155106-mutt-send-email-mst@redhat.com> References: <1426756391-26585-1-git-send-email-kraxel@redhat.com> <1426756391-26585-2-git-send-email-kraxel@redhat.com> <20150319123940-mutt-send-email-mst@redhat.com> <1426847327.32097.60.camel@nilsson.home.kraxel.org> <20150321225356-mutt-send-email-mst@redhat.com> <1427097238.6365.27.camel@nilsson.home.kraxel.org> <1427118292.27137.39.camel@nilsson.home.kraxel.org> <20150323144803-mutt-send-email-mst@redhat.com> <1427120855.27137.55.camel@nilsson.home.kraxel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427120855.27137.55.camel@nilsson.home.kraxel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 23, 2015 at 03:27:35PM +0100, Gerd Hoffmann wrote: > Hi, > > > > > > You are doing leXXX everywhere, that's VERSION_1 dependency. > > > > > virtio_cread will do byteswaps differently without VERSION_1. > > > > > Just don't go there. > > > So to clarify, you dislike using __virtio32 in virtio input header? > > Well, as I understand things __virtio32 implies byteorder depends on > whenever we are using VERSION_1 or not. And non-transitional drivers > should not need it as everything is by definition little endian. > > So, yes, your suggestion to just require VERSION_1 in the driver implies > in my eyes that there should be no reason to use __virtio32 instead of > __le32. > > Or do I miss something here? > > cheers, > Gerd > You are right but then if you do require VERSION_1 then __virtio32 becomes identical to __le32. There's some runtime overhead as we check on each access, but it shouldn't matter here, right? I guess we could add virtio_cread_le - is this what you'd like? -- MST