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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 2AFBFC169C4 for ; Tue, 29 Jan 2019 13:09:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 051F220989 for ; Tue, 29 Jan 2019 13:09:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727470AbfA2NJL (ORCPT ); Tue, 29 Jan 2019 08:09:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49314 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725601AbfA2NJL (ORCPT ); Tue, 29 Jan 2019 08:09:11 -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 3941D88E48; Tue, 29 Jan 2019 13:09:10 +0000 (UTC) Received: from gondolin (dhcp-192-213.str.redhat.com [10.33.192.213]) by smtp.corp.redhat.com (Postfix) with ESMTP id 57FE1600C6; Tue, 29 Jan 2019 13:09:08 +0000 (UTC) Date: Tue, 29 Jan 2019 14:09:05 +0100 From: Cornelia Huck To: Michael Mueller Cc: KVM Mailing List , Linux-S390 Mailing List , linux-kernel@vger.kernel.org, Martin Schwidefsky , Heiko Carstens , Christian Borntraeger , Janosch Frank , David Hildenbrand , Halil Pasic , Pierre Morel Subject: Re: [PATCH v6 11/13] KVM: s390: add functions to (un)register GISC with GISA Message-ID: <20190129140905.288d750a.cohuck@redhat.com> In-Reply-To: <20190124125939.130763-12-mimu@linux.ibm.com> References: <20190124125939.130763-1-mimu@linux.ibm.com> <20190124125939.130763-12-mimu@linux.ibm.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 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 29 Jan 2019 13:09:10 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 24 Jan 2019 13:59:37 +0100 Michael Mueller wrote: > Add the Interruption Alert Mask (IAM) to the architecture specific > kvm struct. This mask in the GISA is used to define for which ISC > a GIB alert will be issued. > > The functions kvm_s390_gisc_register() and kvm_s390_gisc_unregister() > are used to (un)register a GISC (guest ISC) with a virtual machine and > its GISA. > > Upon successful completion, kvm_s390_gisc_register() returns the > ISC to be used for GIB alert interruptions. A negative return code > indicates an error during registration. > > Theses functions will be used by other adapter types like AP and PCI to > request pass-through interruption support. > > Signed-off-by: Michael Mueller > --- > arch/s390/include/asm/kvm_host.h | 13 +++++ > arch/s390/kvm/interrupt.c | 117 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 130 insertions(+) > > +int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc) > +{ > + struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; > + u8 alert_mask; > + > + if (!gi->origin) > + return -ENODEV; > + if (gisc > MAX_ISC) > + return -ERANGE; > + > + spin_lock(&gi->alert.ref_lock); > + if (gi->alert.ref_count[gisc] == 0) { If the ref_count is 0 here... > + alert_mask = gi->alert.mask | 0x80 >> gisc; > + WRITE_ONCE(gi->alert.mask, alert_mask); > + } > + gi->alert.ref_count[gisc]++; > + if (gi->alert.ref_count[gisc] == 1) ...it will certainly be 1 here, won't it? Can you do all of the manipulations in a single if branch? > + gisa_set_iam(gi->origin, alert_mask); > + spin_unlock(&gi->alert.ref_lock); > + > + return gib->nisc; > +}