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 EBC62C43381 for ; Fri, 15 Mar 2019 13:41:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2B29218AC for ; Fri, 15 Mar 2019 13:41:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729169AbfCONlx (ORCPT ); Fri, 15 Mar 2019 09:41:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11365 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727705AbfCONlw (ORCPT ); Fri, 15 Mar 2019 09:41:52 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4B01530F8DAC; Fri, 15 Mar 2019 13:41:52 +0000 (UTC) Received: from gondolin (dhcp-192-222.str.redhat.com [10.33.192.222]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5843D60BE6; Fri, 15 Mar 2019 13:41:43 +0000 (UTC) Date: Fri, 15 Mar 2019 14:41:41 +0100 From: Cornelia Huck To: Pierre Morel Cc: borntraeger@de.ibm.com, alex.williamson@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, akrowiak@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 v5 1/7] s390: ap: kvm: add PQAP interception for AQIC Message-ID: <20190315144141.100f2be7.cohuck@redhat.com> In-Reply-To: References: <1552493104-30510-1-git-send-email-pmorel@linux.ibm.com> <1552493104-30510-2-git-send-email-pmorel@linux.ibm.com> <20190315112032.13b259c2.cohuck@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Fri, 15 Mar 2019 13:41:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 15 Mar 2019 14:26:34 +0100 Pierre Morel wrote: > Conclusion: we must handle this in userland, it will have the benefit > to keep old behavior when there is no callback. > OLD QEMU will not see change as they will not set aqic facility > NEW QEMU will handle this correctly. > > In this case we also do not need to handle all other tests here but can > move it to the callback as Tony wanted. > > Would you agree with something simple like: > > static int handle_pqap(struct kvm_vcpu *vcpu) > { > int ret = -EOPNOTSUPP; > > /* Verify that the hook callback is registered and call it */ > if (pqap_hook) > if (try_module_get(pqap_hook->owner)) { > ret = pqap_hook->hook(vcpu); > module_put(pqap_hook->owner); > } > return ret; > } > > All other tests in QEMU and in the callback. With the hook checking for priv, fc, etc.? Yeah, might work. But don't count on my feedback too much right now, better wait for others' comments :) I'll resume in April, if needed.