From nobody Sun Apr 28 00:20:24 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1489658339545858.1018493912287; Thu, 16 Mar 2017 02:58:59 -0700 (PDT) Received: from localhost ([::1]:42308 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1coSBO-0003wb-EB for importer@patchew.org; Thu, 16 Mar 2017 05:58:58 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34039) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1coSAW-0003lq-9c for qemu-devel@nongnu.org; Thu, 16 Mar 2017 05:58:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1coSAT-0007ZR-6M for qemu-devel@nongnu.org; Thu, 16 Mar 2017 05:58:04 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44895) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1coSAS-0007Yv-U9 for qemu-devel@nongnu.org; Thu, 16 Mar 2017 05:58:01 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v2G9rgQA077464 for ; Thu, 16 Mar 2017 05:57:59 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0a-001b2d01.pphosted.com with ESMTP id 2978fj90u5-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 16 Mar 2017 05:57:58 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 16 Mar 2017 09:57:54 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v2G9vr8C25493576; Thu, 16 Mar 2017 09:57:53 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5F24711C06C; Thu, 16 Mar 2017 09:57:34 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2904411C04A; Thu, 16 Mar 2017 09:57:34 +0000 (GMT) Received: from gondolin.boeblingen.de.ibm.com (unknown [9.152.224.55]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Thu, 16 Mar 2017 09:57:34 +0000 (GMT) From: Cornelia Huck To: qemu-devel@nongnu.org Date: Thu, 16 Mar 2017 10:57:50 +0100 X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170316095750.26952-1-cornelia.huck@de.ibm.com> References: <20170316095750.26952-1-cornelia.huck@de.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17031609-0012-0000-0000-000004E89FDE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17031609-0013-0000-0000-000017A3EDE3 Message-Id: <20170316095750.26952-2-cornelia.huck@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-03-16_08:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=3 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703160080 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH for-2.9 1/1] s390x/css: reassign subchannel if schid is changed after migration X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Cornelia Huck , borntraeger@de.ibm.com, Dong Jia Shi , agraf@suse.de, qemu-stable@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Dong Jia Shi The subchannel is a means to access a device. While the device number is assigned by the administrator, the subchannel number is assigned by the channel subsystem in an ascending order on cold and hot plug. When doing unplug and replug operations, the same device may end up on a different subchannel; for example - We start with a device fe.1.2222, which ends up at subchannel fe.1.0000. - Now we detach the device, attach a device fe.1.3333 (which would get the now-free subchannel fe.1.0000), re-attach fe.1.2222 (which ends up at subchannel fe.1.0001) and detach fe.1.3333. - We now have the same device (fe.1.2222) available to the guest; it just shows up on a different subchannel. In such a case, the subchannel numbers are different from what a QEMU would create during cold plug when parsing the command line. As this would cause a guest visible change on migration, we do restore the source system's value of the subchannel number on load. So we are now fine from the guest perspective. From the host perspective this will cause an inconsistent state in our internal data structures, though. For example, the subchannel 0 might not be at array position 0. This will lead to problems when we continue doing hot (un/re) plug operations. Let's fix this by cleaning up our internal data structures. Reported-by: Cornelia Huck Signed-off-by: Dong Jia Shi Cc: qemu-stable@nongnu.org Signed-off-by: Cornelia Huck --- hw/s390x/css.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/hw/s390x/css.c b/hw/s390x/css.c index e32b2a4d42..37caa98195 100644 --- a/hw/s390x/css.c +++ b/hw/s390x/css.c @@ -1675,12 +1675,27 @@ void subch_device_save(SubchDev *s, QEMUFile *f) =20 int subch_device_load(SubchDev *s, QEMUFile *f) { + SubchDev *old_s; + uint16_t old_schid =3D s->schid; int i; =20 s->cssid =3D qemu_get_byte(f); s->ssid =3D qemu_get_byte(f); s->schid =3D qemu_get_be16(f); s->devno =3D qemu_get_be16(f); + /* Re-assign subch. */ + if (old_schid !=3D s->schid) { + old_s =3D channel_subsys.css[s->cssid]->sch_set[s->ssid]->sch[old_= schid]; + /* + * (old_s !=3D s) means that some other device has its correct + * subchannel already assigned (in load). + */ + if (old_s =3D=3D s) { + css_subch_assign(s->cssid, s->ssid, old_schid, s->devno, NULL); + } + /* It's OK to re-assign without a prior de-assign. */ + css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, s); + } s->thinint_active =3D qemu_get_byte(f); /* SCHIB */ /* PMCW */ --=20 2.11.0