From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751670AbdAMNbS (ORCPT ); Fri, 13 Jan 2017 08:31:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56984 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751595AbdAMNbR (ORCPT ); Fri, 13 Jan 2017 08:31:17 -0500 Date: Fri, 13 Jan 2017 15:31:14 +0200 From: "Michael S. Tsirkin" To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, Jason Wang , virtualization@lists.linux-foundation.org Subject: Re: [PATCH] virtio_mmio: expose header to userspace Message-ID: <20170113152618-mutt-send-email-mst@kernel.org> References: <1484257033-11032-1-git-send-email-mst@redhat.com> <20170113075822.GA31777@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170113075822.GA31777@infradead.org> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 13 Jan 2017 13:31:17 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 12, 2017 at 11:58:22PM -0800, Christoph Hellwig wrote: > On Thu, Jan 12, 2017 at 11:37:22PM +0200, Michael S. Tsirkin wrote: > > It's handy for userspace emulators like QEMU. > > But it's not actually a userspace API - it's an on the write protocol. We do this for all other virtio transports, mmio shouldn't be any different. > so: NAK. We'll have to agree to disagree on this one. It's the interface beween linux and the hypervisor. It isn't any less stable than the one to userspace, for better or worse kvm (ab)uses uapi for that. Compare also to include/uapi/linux/kvm_para.h etc. -- MST