From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel De Graaf Subject: Re: [PATCH RFC] xen/console: buffer and show origin of guest PV writes Date: Tue, 13 Aug 2013 13:47:58 -0400 Message-ID: <520A714E.8010600@tycho.nsa.gov> References: <1376411659-3809-1-git-send-email-dgdegra@tycho.nsa.gov> <520A805402000078000EBA14@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1V9IkX-0003ZO-F2 for xen-devel@lists.xenproject.org; Tue, 13 Aug 2013 17:51:17 +0000 In-Reply-To: <520A805402000078000EBA14@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel , Keir Fraser , Ian.Campbell@citrix.com List-Id: xen-devel@lists.xenproject.org On 08/13/2013 12:52 PM, Jan Beulich wrote: >>>> On 13.08.13 at 18:34, Daniel De Graaf wrote: >> 1. HVM guests' output is currently limited to printable characters; do >> we want to implement the same restriction on PV guests? > > Would seem to make sense. It seems only dom0 will try to use control characters under normal conditions, so this shouldn't cause any issues (hopefully). >> 2. The prefix on the serial console for PV output is "(XEN) d5: ", while >> HVM output is still "(XEN) HVM5: "; should these be made consistent? > > Uniformly using e.g. "(Dom%d) " instead of "(XEN) " for domain output > might be best? I think this makes sense as a way to distinguish guest output from Xen output regarding a guest. This will probably require introducing a vprintk-ish function to add the guest domid argument. The original version of this patch used "(%d) ", but I think "(d%d) " or "(dom%d) " may end up being clearer. >> 3. Should we change to allowing console output by default, since it is >> now controlled by log levels? > > I don't think we should, not the least because guest output doesn't > really specify a log level, and default log level messages make it > through with default options. The existing HVM guest output is done with XENLOG_G_DEBUG, which was copied for the PV guest output. The default value of guest_loglvl on a debug build includes this output, but on a non-debug build hides it. > Will have to look at the patch itself later, but you should have Cc-ed > Keir in any case (as he will eventually need to ack it). > > Jan Ah, for some reason I didn't have him on the original list. I have added him to this message to highlight the thread and will fix that on a resend. -- Daniel De Graaf National Security Agency