Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752108AbaKZJKK (ORCPT ); Wed, 26 Nov 2014 04:10:10 -0500 Received: from e06smtp16.uk.ibm.com ([195.75.94.112]:46660 "EHLO e06smtp16.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750876AbaKZJKG (ORCPT ); Wed, 26 Nov 2014 04:10:06 -0500 Date: Wed, 26 Nov 2014 10:09:54 +0100 From: Cornelia Huck To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, David Miller , rusty@au1.ibm.com, nab@linux-iscsi.org, pbonzini@redhat.com, Rusty Russell , Christian Borntraeger , linux390@de.ibm.com, Martin Schwidefsky , Heiko Carstens , Pawel Moll , Ohad Ben-Cohen , Sudeep Dutt , Ashutosh Dixit , Greg Kroah-Hartman , Nikhil Rao , Siva Yerramreddy , lguest@lists.ozlabs.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v4 04/42] virtio: disable virtio 1.0 in transports Message-ID: <20141126100954.3811e594.cornelia.huck@de.ibm.com> In-Reply-To: <20141125212011.GA22343@redhat.com> References: <1416933600-21398-1-git-send-email-mst@redhat.com> <1416933600-21398-5-git-send-email-mst@redhat.com> <20141125182942.3890fe7b.cornelia.huck@de.ibm.com> <20141125212011.GA22343@redhat.com> Organization: IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz =?UTF-8?B?R2VzY2jDpGZ0c2bDvGhydW5nOg==?= Dirk Wittkopp Sitz der Gesellschaft: =?UTF-8?B?QsO2Ymxpbmdlbg==?= Registergericht: Amtsgericht Stuttgart, HRB 243294 X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14112609-0025-0000-0000-00000298281B Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 25 Nov 2014 23:20:11 +0200 "Michael S. Tsirkin" wrote: > On Tue, Nov 25, 2014 at 06:29:42PM +0100, Cornelia Huck wrote: > > On Tue, 25 Nov 2014 18:41:35 +0200 > > "Michael S. Tsirkin" wrote: > > > > > disable virtio 1.0 in transports that don't > > > support it yet. > > > > I'd prefer if you disabled it for _every_ transport in this patch, > > until the needed infrastructure is in place. Else this is a bit > > confusing. > > Well the only transports left are pci and rpoc, and these only > read the low 32 bit of the features from the device - > so there's nothing to clear. > > E.g. the following would be even more confusing, would it not: > > u32 features; > .... > features &= ~BIT_ULL(VIRTIO_F_VERSION_1); > > Agree? Maybe you should tweak the patch description a bit and mention that you only disable virtio 1.0 for transports where it is actually needed? (...) > > FWIW, as negotiating a revision >= 1 is a pre-req for virtio 1.0 > > support on ccw, virtio 1.0 is already implicitly disabled. > > Ah, you mean device guarantees that VIRTIO_F_VERSION_1 isn't set > if guest sets revision to 0? Yes, the bit will not be offered if the revision is 0 or has not been set at all. > In that case it's probably best to drop this from both ccw > devices. There's only one ccw transport :) The old s390 virtio transport in kvm_virtio.c is not part of virtio 1.0. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/