From patchwork Thu Jan 23 17:02:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Huth X-Patchwork-Id: 11349111 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 82508924 for ; Thu, 23 Jan 2020 19:34:48 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 58E0A24125 for ; Thu, 23 Jan 2020 19:34:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GN3DEhzh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58E0A24125 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:60162 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iuiFb-0002Hd-G2 for patchwork-qemu-devel@patchwork.kernel.org; Thu, 23 Jan 2020 14:34:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46522) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iufss-00054e-Lg for qemu-devel@nongnu.org; Thu, 23 Jan 2020 12:03:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iufsr-0002ei-Fm for qemu-devel@nongnu.org; Thu, 23 Jan 2020 12:03:10 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:20343 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iufsr-0002eX-Cs for qemu-devel@nongnu.org; Thu, 23 Jan 2020 12:03:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579798989; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=NWb4XuDCs4n0z+2XBax5eQCHpFm5HKv3ZHt9i1D5kmI=; b=GN3DEhzhjDZJkvN3WWsFMG2C2L7bcLGt0PtiCbSYAJkspI38jXaQodPEkfTuyOQLxFZq+l fA56sXJiJDCbcQrpYNlZQtkvDWbh7aiSTpZPO9SH2cxqwdRtRV28i+/qBrh/HcSES4HvsA oTGew0CFbGayJPxVTLU+Lzbtyp64IN0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-191-Mv-vsQZnN92QuJdzqsTeJw-1; Thu, 23 Jan 2020 12:03:07 -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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9D3E81005512; Thu, 23 Jan 2020 17:03:04 +0000 (UTC) Received: from thuth.com (ovpn-116-64.ams2.redhat.com [10.36.116.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3505A620D8; Thu, 23 Jan 2020 17:03:00 +0000 (UTC) From: Thomas Huth To: Cornelia Huck , David Hildenbrand , qemu-devel@nongnu.org Subject: [PATCH] hw/s390x: Add a more verbose comment about get_machine_class() and the wrappers Date: Thu, 23 Jan 2020 18:02:56 +0100 Message-Id: <20200123170256.12386-1-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: Mv-vsQZnN92QuJdzqsTeJw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, Matthew Rosato Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" While working on the "Enable adapter interruption suppression again" recently, I had to discover that the meaning of get_machine_class() and the related *_allowed() wrappers is not very obvious. Add a more verbose comment here to clarify how these should be used. Signed-off-by: Thomas Huth Reviewed-by: David Hildenbrand --- hw/s390x/s390-virtio-ccw.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index e0e28139a2..7fb389f0e5 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -505,6 +505,18 @@ static inline void machine_set_dea_key_wrap(Object *obj, bool value, static S390CcwMachineClass *current_mc; +/* + * Get the class of the s390-ccw-virtio machine that is currently in use. + * Note: libvirt is using the "none" machine to probe for the features of the + * host CPU, so in case this is called with the "none" machine, the function + * returns the TYPE_S390_CCW_MACHINE base class. In this base class, all the + * various "*_allowed" variables are enabled, so that the *_allowed() wrappers + * below return the correct default value for the "none" machine. + * Attention! Do *not* add additional new wrappers for CPU features (e.g. like + * the ri_allowed() wrapper) via this mechanism anymore. CPU features should + * be handled via the CPU models, i.e. checking with cpu_model_allowed() during + * CPU initialization and s390_has_feat() later should be sufficient. + */ static S390CcwMachineClass *get_machine_class(void) { if (unlikely(!current_mc)) { @@ -521,19 +533,16 @@ static S390CcwMachineClass *get_machine_class(void) bool ri_allowed(void) { - /* for "none" machine this results in true */ return get_machine_class()->ri_allowed; } bool cpu_model_allowed(void) { - /* for "none" machine this results in true */ return get_machine_class()->cpu_model_allowed; } bool hpage_1m_allowed(void) { - /* for "none" machine this results in true */ return get_machine_class()->hpage_1m_allowed; }