From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937500AbcKOOfP (ORCPT ); Tue, 15 Nov 2016 09:35:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59462 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935363AbcKOOfK (ORCPT ); Tue, 15 Nov 2016 09:35:10 -0500 Date: Tue, 15 Nov 2016 16:35:06 +0200 From: "Michael S. Tsirkin" To: Namhyung Kim Cc: virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, LKML , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Anthony Liguori , Anton Vorontsov , Colin Cross , Kees Cook , Tony Luck , Steven Rostedt , Ingo Molnar , Minchan Kim Subject: Re: [PATCH 1/3] virtio: Basic implementation of virtio pstore driver Message-ID: <20161115163342-mutt-send-email-mst@kernel.org> References: <20160820080744.10344-1-namhyung@kernel.org> <20160820080744.10344-2-namhyung@kernel.org> <20161110182611-mutt-send-email-mst@kernel.org> <20161115045021.GA15992@danjae.aot.lge.com> <20161115065658-mutt-send-email-mst@kernel.org> <20161115055011.GB15992@danjae.aot.lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161115055011.GB15992@danjae.aot.lge.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 15 Nov 2016 14:35:09 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 15, 2016 at 02:50:11PM +0900, Namhyung Kim wrote: > On Tue, Nov 15, 2016 at 07:06:28AM +0200, Michael S. Tsirkin wrote: > > On Tue, Nov 15, 2016 at 01:50:21PM +0900, Namhyung Kim wrote: > > > On Thu, Nov 10, 2016 at 06:39:55PM +0200, Michael S. Tsirkin wrote: > > > [SNIP] > > > > > +struct virtio_pstore_fileinfo { > > > > > + __virtio64 id; > > > > > + __virtio32 count; > > > > > + __virtio16 type; > > > > > + __virtio16 unused; > > > > > + __virtio32 flags; > > > > > + __virtio32 len; > > > > > + __virtio64 time_sec; > > > > > + __virtio32 time_nsec; > > > > > + __virtio32 reserved; > > > > > +}; > > > > > + > > > > > +struct virtio_pstore_config { > > > > > + __virtio32 bufsize; > > > > > +}; > > > > > + > > > > > > > > What exactly does each field mean? I'm especially > > > > interested in time fields - maintaining a consistent > > > > time between host and guest is not a simple problem. > > > > > > These are required by pstore and will be used to create corresponding > > > files in the pstore filesystem. The time fields are for mtime and > > > ctime and, I think, it's just a hint for user and doesn't require > > > strict consistency. > > > > Pls add documentation. I would just drop hints for now. > > Well, I'll add docmentation. But I think just dropping might not good > since they all have host time and it's helpful to know their relative > difference in guest. > > Thanks, > Namhyung If it's part of host/guest ABI it needs to be better defined. "It's just a hint does not need to be exact" is too vague, we need to specify what kind of change will or will not break guests. -- MST From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 1/3] virtio: Basic implementation of virtio pstore driver Date: Tue, 15 Nov 2016 16:35:06 +0200 Message-ID: <20161115163342-mutt-send-email-mst@kernel.org> References: <20160820080744.10344-1-namhyung@kernel.org> <20160820080744.10344-2-namhyung@kernel.org> <20161110182611-mutt-send-email-mst@kernel.org> <20161115045021.GA15992@danjae.aot.lge.com> <20161115065658-mutt-send-email-mst@kernel.org> <20161115055011.GB15992@danjae.aot.lge.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: virtio-dev@lists.oasis-open.org, Tony Luck , Kees Cook , kvm@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= , Anton Vorontsov , LKML , Steven Rostedt , qemu-devel@nongnu.org, Minchan Kim , Anthony Liguori , Colin Cross , Paolo Bonzini , virtualization@lists.linux-foundation.org, Ingo Molnar To: Namhyung Kim Return-path: Content-Disposition: inline In-Reply-To: <20161115055011.GB15992@danjae.aot.lge.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org On Tue, Nov 15, 2016 at 02:50:11PM +0900, Namhyung Kim wrote: > On Tue, Nov 15, 2016 at 07:06:28AM +0200, Michael S. Tsirkin wrote: > > On Tue, Nov 15, 2016 at 01:50:21PM +0900, Namhyung Kim wrote: > > > On Thu, Nov 10, 2016 at 06:39:55PM +0200, Michael S. Tsirkin wrote: > > > [SNIP] > > > > > +struct virtio_pstore_fileinfo { > > > > > + __virtio64 id; > > > > > + __virtio32 count; > > > > > + __virtio16 type; > > > > > + __virtio16 unused; > > > > > + __virtio32 flags; > > > > > + __virtio32 len; > > > > > + __virtio64 time_sec; > > > > > + __virtio32 time_nsec; > > > > > + __virtio32 reserved; > > > > > +}; > > > > > + > > > > > +struct virtio_pstore_config { > > > > > + __virtio32 bufsize; > > > > > +}; > > > > > + > > > > > > > > What exactly does each field mean? I'm especially > > > > interested in time fields - maintaining a consistent > > > > time between host and guest is not a simple problem. > > > > > > These are required by pstore and will be used to create corresponding > > > files in the pstore filesystem. The time fields are for mtime and > > > ctime and, I think, it's just a hint for user and doesn't require > > > strict consistency. > > > > Pls add documentation. I would just drop hints for now. > > Well, I'll add docmentation. But I think just dropping might not good > since they all have host time and it's helpful to know their relative > difference in guest. > > Thanks, > Namhyung If it's part of host/guest ABI it needs to be better defined. "It's just a hint does not need to be exact" is too vague, we need to specify what kind of change will or will not break guests. -- MST From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33571) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c6epN-0005Zp-Sj for qemu-devel@nongnu.org; Tue, 15 Nov 2016 09:35:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c6epK-0001qL-RF for qemu-devel@nongnu.org; Tue, 15 Nov 2016 09:35:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54064) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c6epK-0001pv-MA for qemu-devel@nongnu.org; Tue, 15 Nov 2016 09:35:10 -0500 Date: Tue, 15 Nov 2016 16:35:06 +0200 From: "Michael S. Tsirkin" Message-ID: <20161115163342-mutt-send-email-mst@kernel.org> References: <20160820080744.10344-1-namhyung@kernel.org> <20160820080744.10344-2-namhyung@kernel.org> <20161110182611-mutt-send-email-mst@kernel.org> <20161115045021.GA15992@danjae.aot.lge.com> <20161115065658-mutt-send-email-mst@kernel.org> <20161115055011.GB15992@danjae.aot.lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161115055011.GB15992@danjae.aot.lge.com> Subject: Re: [Qemu-devel] [PATCH 1/3] virtio: Basic implementation of virtio pstore driver List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Namhyung Kim Cc: virtio-dev@lists.oasis-open.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, LKML , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Anthony Liguori , Anton Vorontsov , Colin Cross , Kees Cook , Tony Luck , Steven Rostedt , Ingo Molnar , Minchan Kim On Tue, Nov 15, 2016 at 02:50:11PM +0900, Namhyung Kim wrote: > On Tue, Nov 15, 2016 at 07:06:28AM +0200, Michael S. Tsirkin wrote: > > On Tue, Nov 15, 2016 at 01:50:21PM +0900, Namhyung Kim wrote: > > > On Thu, Nov 10, 2016 at 06:39:55PM +0200, Michael S. Tsirkin wrote: > > > [SNIP] > > > > > +struct virtio_pstore_fileinfo { > > > > > + __virtio64 id; > > > > > + __virtio32 count; > > > > > + __virtio16 type; > > > > > + __virtio16 unused; > > > > > + __virtio32 flags; > > > > > + __virtio32 len; > > > > > + __virtio64 time_sec; > > > > > + __virtio32 time_nsec; > > > > > + __virtio32 reserved; > > > > > +}; > > > > > + > > > > > +struct virtio_pstore_config { > > > > > + __virtio32 bufsize; > > > > > +}; > > > > > + > > > > > > > > What exactly does each field mean? I'm especially > > > > interested in time fields - maintaining a consistent > > > > time between host and guest is not a simple problem. > > > > > > These are required by pstore and will be used to create corresponding > > > files in the pstore filesystem. The time fields are for mtime and > > > ctime and, I think, it's just a hint for user and doesn't require > > > strict consistency. > > > > Pls add documentation. I would just drop hints for now. > > Well, I'll add docmentation. But I think just dropping might not good > since they all have host time and it's helpful to know their relative > difference in guest. > > Thanks, > Namhyung If it's part of host/guest ABI it needs to be better defined. "It's just a hint does not need to be exact" is too vague, we need to specify what kind of change will or will not break guests. -- MST