From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54487) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuO2v-0004xS-Tt for qemu-devel@nongnu.org; Thu, 05 Nov 2015 12:09:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZuO2r-0001rz-6m for qemu-devel@nongnu.org; Thu, 05 Nov 2015 12:09:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56662) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZuO2r-0001rv-0n for qemu-devel@nongnu.org; Thu, 05 Nov 2015 12:09:53 -0500 References: <1446725610.30393.23.camel@redhat.com> <563B5E37.2040701@redhat.com> <8737wk1m0p.fsf@linaro.org> <563B8C4A.70307@redhat.com> From: Paolo Bonzini Message-ID: <563B8D59.1040008@redhat.com> Date: Thu, 5 Nov 2015 18:09:45 +0100 MIME-Version: 1.0 In-Reply-To: <563B8C4A.70307@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] virtio-gpu doesn't build if you do a linux-headers update from kvm/next List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek , =?UTF-8?Q?Alex_Benn=c3=a9e?= Cc: Peter Maydell , QEMU Developers , Gerd Hoffmann On 05/11/2015 18:05, Laszlo Ersek wrote: >> > Surely the kernel uapi includes is that textual format. Once stuff is >> > accepted into the master kernel tree there is your stable API. > What is uapi for? If it is for QEMU (the userspace process) to consume > the host kernel's services, then I agree. uapi = Userspace API. > If uapi is for the guest kernel to consume (= drive) QEMU's virtual > hardware, then I strongly disagree. In that case Linux is just one of > the possible guests that can drive that hardware. Kernel-only headers can and will include uapi headers, though not the other way round. So there can be indeed a case where a typo in uapi headers causes both QEMU and the guest kernel to deviate from the spec. > (Side point: and QEMU is just one of the emulators / hypervisors that > can provide that hardware. Which is why the actual hardware description > should exist independently of both.) Typically it exists as an industry standard (e.g. the virtio specification) or a datasheet. Paolo > I'll elaborate elsewhere in the thread.