From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH RFC] xen: arm: Log a warning message when a deprecated hypercall is used Date: Tue, 27 Jan 2015 17:14:50 +0000 Message-ID: <1422378890.16180.17.camel@citrix.com> References: <1421751134-9172-1-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ard Biesheuvel Cc: Keir Fraser , Stefano Stabellini , Julien Grall , tim@xen.org, xen-devel@lists.xen.org, Jan Beulich , Anthony PERARD List-Id: xen-devel@lists.xenproject.org On Tue, 2015-01-27 at 11:51 +0000, Ard Biesheuvel wrote: > On 20 January 2015 at 10:52, Ian Campbell wrote: > > A few folks have been caught out by OSes which call e.g. > > HYPERVISOR_event_channel_op_compat which has been deprecated since > > 3.2.2 (i.e. long before Xen on ARM). Existing x86 code can still > > safely and quietly using those calls, waiting for an unsuspecting ARM > > porter to turn up and trip over it. This turns out to be rather > > perplexing when it happens, since it can be obscured e.g. by various > > conditionals like __XEN_INTERFACE_VERSION__ what is actually being > > called. > > > > Note that I'm making a distinction here between hypercalls which are > > simply not used/implemented on arm (yet) and those which were > > deprecated and replaced by a newer variant prior to Xen on ARM even > > being invented. The latter will never be implemented on ARM and have > > non-deprecated aliases leading to confusion so those are the ones for > > which a warning is useful. > > > > Signed-off-by: Ian Campbell > > Cc: Jan Beulich > > Cc: Keir Fraser > > Cc: Ard Biesheuvel > > Cc: Anthony PERARD > > --- > > RFC since I'm not sure how extreme our reaction ought to be here, e.g. > > I considered domain_crash() or even panic() when in a debug build. A > > XENLOG_DEBUG message is about the most benign of the options. > > > > Jan/Keir, although this is ARM specific I'd welcome your views as > > x86/REST maintainers. > > > > Ard, I've not actually run this -- any chance you could re-b0rk your > > Tianocore image and give it a go? > > Hello, > > I have been trying not to code against a moving Xen target, so I > haven't had a go with this yet. Once I go back to testing the GICv3 > support, I will need to rebuild Xen and kernels etc anyway so I will > give it a try (by the end of the week) Thanks, no particular hurry, this patch isn't super urgent or anthing. Ian.