From patchwork Wed Dec 20 12:53:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Borntraeger X-Patchwork-Id: 13500049 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4AF9225754; Wed, 20 Dec 2023 12:53:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="PMun4O18" Received: from pps.filterd (m0353728.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3BKAg9f2015309; Wed, 20 Dec 2023 12:53:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=BWqsX3YXID+rpxJ8zvA26UBhBnUaEVMLLeznHICyurM=; b=PMun4O18/bhtkMg+ww3enXNpbYwTCiaQmGVGzuBWFA+dnvIkTDHrwKa9JMIIOK1X+L44 9Hl3FP05nbk2gsostf5fQjLmu30LuKZXtjJIFh6XTJZulSflMcVuIanGvF6WB0RkCdkQ zOwGVPN4wWk4cFoz2ZxT/b8X9DjIMlPHDKuV4+bvGC2Pmm8EFPiSW4e33DC5CW604pdz Fq/clvJuxAYFYrDCCU56nQSteGpTU+EUimRWp6cUdv6szfqRNxYrVTads0WfjNPnQkyw eajiPsSIBHkgR9gke9NilJXcjdo24wLxoSY3TC+ktuqka7mkUUJH51xqfHATCwRCQfPg qg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3v3xrbjwj4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Dec 2023 12:53:24 +0000 Received: from m0353728.ppops.net (m0353728.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3BKBpFT5006561; Wed, 20 Dec 2023 12:53:23 GMT Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3v3xrbjwhh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Dec 2023 12:53:23 +0000 Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3BKA6vW9004856; Wed, 20 Dec 2023 12:53:22 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3v1pkyxja8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Dec 2023 12:53:22 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 3BKCrJDG43254104 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Dec 2023 12:53:19 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 042972004B; Wed, 20 Dec 2023 12:53:19 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E6EF120043; Wed, 20 Dec 2023 12:53:18 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 20 Dec 2023 12:53:18 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 25651) id 88BF0E03E5; Wed, 20 Dec 2023 13:53:18 +0100 (CET) From: Christian Borntraeger To: KVM Cc: Christian Borntraeger , Janosch Frank , David Hildenbrand , linux-s390 , Thomas Huth , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Marc Hartmayer Subject: [PATCH v2] KVM: s390: vsie: fix race during shadow creation Date: Wed, 20 Dec 2023 13:53:17 +0100 Message-ID: <20231220125317.4258-1-borntraeger@linux.ibm.com> X-Mailer: git-send-email 2.41.0 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 0B6MWMXV_hQ9xi0E8v8C8dq2-Ik284_g X-Proofpoint-GUID: C9CtnsnfGJfO3HfzZESPTeYUViS1-_kg X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-20_02,2023-12-14_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 lowpriorityscore=0 mlxlogscore=830 spamscore=0 mlxscore=0 suspectscore=0 adultscore=0 priorityscore=1501 bulkscore=0 malwarescore=0 clxscore=1015 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2312200091 Right now it is possible to see gmap->private being zero in kvm_s390_vsie_gmap_notifier resulting in a crash. This is due to the fact that we add gmap->private == kvm after creation: static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) { [...] gmap = gmap_shadow(vcpu->arch.gmap, asce, edat); if (IS_ERR(gmap)) return PTR_ERR(gmap); gmap->private = vcpu->kvm; Let children inherit the private field of the parent. Reported-by: Marc Hartmayer Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization") Cc: Cc: David Hildenbrand Signed-off-by: Christian Borntraeger Reviewed-by: Janosch Frank Reviewed-by: David Hildenbrand Reviewed-by: Claudio Imbrenda --- v1->v2: let the child inherit private from parent instead of accessing the parent in the notifier arch/s390/kvm/vsie.c | 1 - arch/s390/mm/gmap.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 8207a892bbe2..db9a180de65f 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -1220,7 +1220,6 @@ static int acquire_gmap_shadow(struct kvm_vcpu *vcpu, gmap = gmap_shadow(vcpu->arch.gmap, asce, edat); if (IS_ERR(gmap)) return PTR_ERR(gmap); - gmap->private = vcpu->kvm; vcpu->kvm->stat.gmap_shadow_create++; WRITE_ONCE(vsie_page->gmap, gmap); return 0; diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 6f96b5a71c63..8da39deb56ca 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -1691,6 +1691,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, return ERR_PTR(-ENOMEM); new->mm = parent->mm; new->parent = gmap_get(parent); + new->private = parent->private; new->orig_asce = asce; new->edat_level = edat_level; new->initialized = false;