From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99F9DC43381 for ; Fri, 1 Mar 2019 12:36:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 671AD20850 for ; Fri, 1 Mar 2019 12:36:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733100AbfCAMgV convert rfc822-to-8bit (ORCPT ); Fri, 1 Mar 2019 07:36:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:2028 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725978AbfCAMgV (ORCPT ); Fri, 1 Mar 2019 07:36:21 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 230D29C170; Fri, 1 Mar 2019 12:36:20 +0000 (UTC) Received: from gondolin (ovpn-117-66.ams2.redhat.com [10.36.117.66]) by smtp.corp.redhat.com (Postfix) with ESMTP id 58C02620D2; Fri, 1 Mar 2019 12:36:12 +0000 (UTC) Date: Fri, 1 Mar 2019 13:36:09 +0100 From: Cornelia Huck To: Christian Borntraeger Cc: pmorel@linux.ibm.com, Tony Krowiak , alex.williamson@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com Subject: Re: [PATCH v4 1/7] s390: ap: kvm: add PQAP interception for AQIC Message-ID: <20190301133609.3ee469dc.cohuck@redhat.com> In-Reply-To: References: <1550849400-27152-1-git-send-email-pmorel@linux.ibm.com> <1550849400-27152-2-git-send-email-pmorel@linux.ibm.com> <9f1d9241-39b9-adbc-d0e9-cb702e609cbc@linux.ibm.com> <4dc59125-7f96-cba8-651b-382ed8f8bff8@linux.ibm.com> <8526f468-9a4d-68d2-3868-0dad5ce16f46@linux.ibm.com> <6058a017-6404-af3c-62ef-2452214ac97c@de.ibm.com> <2391adc2-6611-034c-61c5-feb46e2a751b@de.ibm.com> <20190228122251.75b31f62.cohuck@redhat.com> <20190228145254.2909425e.cohuck@redhat.com> <261a1e22-3703-21a4-e33d-e737651e7d89@linux.ibm.com> <3fedbde5-ef83-c67e-6352-fd492f258009@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 01 Mar 2019 12:36:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 1 Mar 2019 13:05:54 +0100 Christian Borntraeger wrote: > On 01.03.2019 13:03, Pierre Morel wrote: > > On 28/02/2019 15:14, Pierre Morel wrote: > >> On 28/02/2019 14:52, Cornelia Huck wrote: > >>> On Thu, 28 Feb 2019 14:16:09 +0100 > >>> Pierre Morel wrote: > >>> > >>>> On 28/02/2019 12:22, Cornelia Huck wrote: > >>> > >>>>> So, to summarize, the function should do: > >>>>> - Is userspace supposed to emulate everything (!ECA_APIE)? Return > >>>>>     -EOPNOTSUPP to hand control to it. > >>>>> - We are now interpreting the instruction in KVM. Do common checks > >>>>>     (PSTATE etc.) and inject exceptions, if needed. > >>>>> - Now look at the fc; if there's a handler for it, call that; if not > >>>>>     (case does not attempt to call a specific handler, or no handler > >>>>>     registered), inject a specification exception. (Do we want pre-checks > >>>>>     like for facility 65 here, or in the handler?) > >>>>> > >>>>> That response code 0x01 thingy probably needs to go into the specific > >>>>> handler function, if anywhere (don't know the semantics, sorry). > >>>> > >>>> What do you mean with specific handler function? > >>>> > >>>> If you mean a switch around the FC with static function's call, I agree, > >>>> if you mean a jump into a hook I do not agree. > >>> > >>> Ah, ok; so each case (that we want to handle) should call into a > >>> subhandler that does > >>> { > >>>     (... check things like facilities ...) > >>>     if (!specific_hook) > >>>         inject_specif_excp_and_return(); > >>>     ret = specific_hook(); > >>>     if (ret) > >>>         set_resp_code_0x01(); // or in specific_hook()? > >>> } > >>> > >>> ? > >> > >> Yes something in this direction. > > > > Sorry, after reflection, no, we do not want to change the previous behavior so we only handle the AQIC case. > > I think what you wanted to say is the following: > Today (without the patch set) we will answer PQAP with an exception. > With this patch set we want to handle FC==3, but nothing else. So for anything FC!=3 we > will continue to return an exception? > > Correct? > That sounds reasonable; but I don't see how this conflicts with my proposal? Just don't introduce a subfunction for fc != 3...