From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 F3E083D9DAD; Mon, 1 Jun 2026 15:30:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780327819; cv=none; b=SQM+aF5y2KKacaVEgeDVerybTarT8cRDiMsTfcHCa6t5AeB/Iy4CmV/cNONKAPZIXpBIWebtkUPNKLRUywdVyey0tci0p4PbbpCHRChoeFd3wj9HblVxVHWJU7QPnN4dYzOW5kN4sKZTeNBB/h81LJGVHp3dZOL0WUoGbRx0YZc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780327819; c=relaxed/simple; bh=zx6TNjrr5sxF/JXLwJ0ARC1L8V6fY9iLaJ2DLC5EdXg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BBaqB5bxC8jD79ZQ2nm0bP6FgxkRyQpoHStKsGc9xCxuBYC1pKJEaH8bAVNif5/eltmAwiwLWJYgU2LXVUUJrLPD3arAqUmqKSVGUzkAFxfKDF3WW8htT5cR8LRAMU7pz39ZX/HtCcm5GNHGjPNRu2YMuW2OxyhjRwMvHuV5SAo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=pbsrcwqJ; arc=none smtp.client-ip=148.163.158.5 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="pbsrcwqJ" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 651Cl02w3195132; Mon, 1 Jun 2026 15:30:00 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=OP2M1HsEe+DgddDeh HcZonXB7ZpUy8+gPxxm8UoJYtA=; b=pbsrcwqJK+bCZPxNZJZ4WEV71gQ6qCwJt XUvlMlHY2LTHCrF5oAJvN58QJlGy2a13e0DHqiN4+opRWH23Lkci6tiyhzKFxGFo nlLda8LiG6XoVBNrlEZyFv8iQrZXxYdqH7XidZ7ovse+p58ADSanrutK9H0Abtm6 FlMUxW1O8J48HXZkqKwAgUE7yq1D8W/Y1vDG2Q3mQenT7qmI+fE9Tk437L0ZmCSY jvXb19zyTRJCRyeHLA3sPUVNBuoVAqLPju+7XmsLG1cGSQTkxZIqA6bLoIFw42HF DQ2rOyZOFQuPBWM71ZJqZwA0xFS1zHBHj1xs3CNLMjliyVJp8h8Fw== 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 4efqht12yk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 01 Jun 2026 15:29:59 +0000 (GMT) Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 651FO7RD031048; Mon, 1 Jun 2026 15:29:59 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4egakvpvx2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 01 Jun 2026 15:29:59 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 651FTr4m50725128 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 1 Jun 2026 15:29:53 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9178520040; Mon, 1 Jun 2026 15:29:53 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 68C932004B; Mon, 1 Jun 2026 15:29:53 +0000 (GMT) Received: from p-imbrenda.aag-de.ibm.com (unknown [9.52.223.175]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 1 Jun 2026 15:29:53 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com Subject: [PATCH v2 8/8] KVM: s390: Prevent memslots outside the ASCE range Date: Mon, 1 Jun 2026 17:29:51 +0200 Message-ID: <20260601152951.196859-9-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260601152951.196859-1-imbrenda@linux.ibm.com> References: <20260601152951.196859-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 5dZ_XfCxKcOQB-2GlXFSF-um3BPe80yf X-Authority-Analysis: v=2.4 cv=fv/sol4f c=1 sm=1 tr=0 ts=6a1da578 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=1rJwsmJvMo9JdAIlmdgA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjAxMDE1MSBTYWx0ZWRfX8peYSN6aQfEE gToq0kzKYgwEkPCaHomjufsX8nCQSTa0AOQK6bJKPcH+8c3nv+a+JzcstdSQL4a7kne6h5dL7h+ h3cn1cp1mkoqY4JlqGUCwI4w+cGfVMfIzvOrHoJs1lKvGHDCmr9zRsjbHbRkJ8aFA5d1g+iScwW 2QwxJYJVod8g21PIm6ip3TXEbzSgS0qNxHKYM3DqsOfpMwfyQSvFoN8VLKE6Fd7rjH0YFEtjHwU SRFg6xrI1YNNKPra+I6rSnqmjmnB53DaNVE9UMgUVuVRgZtHpRpiRm4xxKxool2QW8npw19DOnt nF4ZK0ThY09ACJUE22dZEXv+3sFdA5EXSRrAPFc+w5rbOXNZ9Jr582FknlIGdQ/Po+lRQimj06k dJeQ9wGTnClHmqoxtmTC22UMdwvGDvBv21ucy1+CZ/VUu3SeJp24B9feArboWMMAERUXqFWTx2f qjqoDFVX5rbnsG2QiYA== X-Proofpoint-ORIG-GUID: 5dZ_XfCxKcOQB-2GlXFSF-um3BPe80yf X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-01_04,2026-05-28_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 spamscore=0 phishscore=0 clxscore=1015 impostorscore=0 suspectscore=0 bulkscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606010151 With KVM_S390_VM_MEM_LIMIT_SIZE, userspace can set the highest address allowed for the VM. Creating a memslot that lies over the maximum address does not make sense and is only a potential source of bugs. Prevent creation of memslots over the maximum address, and prevent the maximum address from being reduced below the end of existing memslots. Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/kvm-s390.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index e09960c2e6ed..1796a7c645a9 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -999,7 +999,10 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att break; } case KVM_S390_VM_MEM_LIMIT_SIZE: { + struct kvm_memslots *slots; + struct kvm_memory_slot *ms; unsigned long new_limit; + int bkt; if (kvm_is_ucontrol(kvm)) return -EINVAL; @@ -1007,6 +1010,8 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att if (get_user(new_limit, (u64 __user *)attr->addr)) return -EFAULT; + guard(mutex)(&kvm->lock); + if (kvm->arch.mem_limit != KVM_S390_NO_MEM_LIMIT && new_limit > kvm->arch.mem_limit) return -E2BIG; @@ -1014,12 +1019,27 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att if (!new_limit) return -EINVAL; - ret = -EBUSY; - if (!kvm->created_vcpus) + if (kvm->created_vcpus) + return -EBUSY; + + ret = 0; + scoped_guard(mutex, &kvm->slots_lock) { + slots = kvm_memslots(kvm); + if (slots && !kvm_memslots_empty(slots)) { + kvm_for_each_memslot(ms, bkt, slots) { + if (gpa_to_gfn(new_limit) < ms->base_gfn + ms->npages) { + ret = -EBUSY; + break; + } + } + } + } + if (!ret) ret = gmap_set_limit(kvm->arch.gmap, gpa_to_gfn(new_limit)); + if (ret) + break; VM_EVENT(kvm, 3, "SET: max guest address: %lu", new_limit); - VM_EVENT(kvm, 3, "New guest asce: 0x%p", - (void *)kvm->arch.gmap->asce.val); + VM_EVENT(kvm, 3, "New guest asce: 0x%p", (void *)kvm->arch.gmap->asce.val); break; } default: @@ -5672,6 +5692,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return -EINVAL; if ((new->base_gfn + new->npages) * PAGE_SIZE > kvm->arch.mem_limit) return -EINVAL; + if (!asce_contains_gfn(kvm->arch.gmap->asce, new->base_gfn + new->npages - 1)) + return -EINVAL; } if (!kvm->arch.migration_mode) -- 2.54.0