From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel De Graaf Subject: Re: [PATCH] hvm: Allow HVM guests to make console_io hypercall. Date: Mon, 30 Sep 2013 10:04:58 -0400 Message-ID: <5249850A.4030306@tycho.nsa.gov> References: <1380316648-21549-1-git-send-email-konrad.wilk@oracle.com> <52494CA902000078000F7E5B@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.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1VQe76-00082z-Sd for xen-devel@lists.xenproject.org; Mon, 30 Sep 2013 14:06:17 +0000 In-Reply-To: <52494CA902000078000F7E5B@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@lists.xenproject.org, Keir Fraser , ian.campbell@citrix.com List-Id: xen-devel@lists.xenproject.org On 09/30/2013 04:04 AM, Jan Beulich wrote: >>>> On 27.09.13 at 23:17, Konrad Rzeszutek Wilk wrote: >> The console_io hypercall is provided for PV guests and for HVM >> guests it is done via the 0xe9 port. However the PV hypercall >> is more efficient as it takes a string rather than one character >> per write. > > While the change itself is fine, there are two questions arising > from me looking at do_console_io() in this context: > > 1) While I can see why VERBOSE ought to control access to > CONSOLEIO_write, I would think CONSOLEIO_read ought to be > constrained to the control domain in any case. I agree on read. Do we still need the restriction on write with non-VERBOSE builds now that domains' output is restricted to the guest debug loglevel? I recall this being discussed briefly when the output changes were being made, but I believe the decision was only that such a change belonged in a different patch. > 2) xsm_console_io(), like quite a few other stubs in xsm/dummy.h, > ignores its "d" parameter and uses current->domain instead. Is > that really the right way (and if so, why are there other stubs > that do honor their inputs)? > > Jan No, this is incorrect - it should be using the parameter, same as any of the other stubs that have a parameter that is always set to current->domain. -- Daniel De Graaf National Security Agency