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Mon, 22 Jun 2026 16:07:41 +0000 (GMT) Received: from p-imbrenda.ehn-de.ibm.com (unknown [9.224.75.30]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 22 Jun 2026 16:07:41 +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, hca@linux.ibm.com, gerald.schaefer@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com Subject: [PATCH v5 6/9] KVM: s390: Fix locking in kvm_s390_set_mem_control() Date: Mon, 22 Jun 2026 18:07:36 +0200 Message-ID: <20260622160739.202044-7-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260622160739.202044-1-imbrenda@linux.ibm.com> References: <20260622160739.202044-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=X4Ni7mTe c=1 sm=1 tr=0 ts=6a395dd2 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=n1h0PExJXEhyPeoWzy0A:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjIyMDE1NyBTYWx0ZWRfX9ygxXx8khHMx paPQSYb2ruRcyXzkPRM49AIuL1qndjl4wRH/qACdkai+0uCifH24S6uRjqT9zwT2b3teeKnqDYQ B7ze+Gnth6Iow/UKqwrflxbC3iVv/IU= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjIyMDE1NyBTYWx0ZWRfX2KmssW+egYSm ENKeRXCD4Z4hcPN6pLkN0nsqgnQtzOmAe3MKX1kfbl7ehzL63xbYjZ/i0GjiGo2lvKjRq/O5gu0 VaLJoig95FKFxzjsn8Nh03uCG9LcG6ijJmxQiO4P3myBLPrMFbKNckrdSpUusFNA0665SM166Mg VpvK1+7N6ouz8BxkDPObQ9Z5JjEZPb75bJ7fqeWVZcHmz6BAPc9hutZEQXBOo4G20UOpCzV6r5v K/U59JWX2fKYcNh2LE6aIRBW3OOvyyKuUiE1LOyUCjZzfzcSSP64TY0UP4hqa86GCAYzshACo5u iAop+kWc3XHYIQcz5t9XI+CnCt5XkQ9cAuB2G8Cf791KTgxjzu3z2FJ3h0Mlokft5/ZN0JlfVnd g70GPKzNiuVFgH9MK4v8fyueHR6iOWLS3ccHigZHK3tAZaizWHWHy9iLWtxVbDc/7oxs09l+gDS dZ34Hxced/kbhjTSQDw== X-Proofpoint-ORIG-GUID: LElD1X0__cs6wVPoXAJzkNqVi-3h2Cov X-Proofpoint-GUID: LElD1X0__cs6wVPoXAJzkNqVi-3h2Cov 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=2026-06-22_03,2026-06-22_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 bulkscore=0 suspectscore=0 spamscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606220157 All subfunctions in kvm_s390_set_mem_control() need to take the kvm->lock, so factor it out of the switch. Also add the missing locking around dat_reset_cmma(). Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/kvm-s390.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ffb20a64d328..93141a68e0dd 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -962,6 +962,8 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att { int ret; + guard(mutex)(&kvm->lock); + switch (attr->attr) { case KVM_S390_VM_MEM_ENABLE_CMMA: ret = -ENXIO; @@ -969,7 +971,6 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att break; VM_EVENT(kvm, 3, "%s", "ENABLE: CMMA support"); - mutex_lock(&kvm->lock); if (kvm->created_vcpus) ret = -EBUSY; else { @@ -978,7 +979,6 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att kvm->arch.use_pfmfi = 0; ret = 0; } - mutex_unlock(&kvm->lock); break; case KVM_S390_VM_MEM_CLR_CMMA: { gfn_t start_gfn = 0; @@ -992,7 +992,8 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att VM_EVENT(kvm, 3, "%s", "RESET: CMMA states"); do { - start_gfn = dat_reset_cmma(kvm->arch.gmap->asce, start_gfn); + scoped_guard(read_lock, &kvm->mmu_lock) + start_gfn = dat_reset_cmma(kvm->arch.gmap->asce, start_gfn); cond_resched(); } while (start_gfn); ret = 0; @@ -1010,8 +1011,6 @@ 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); - new_limit = ALIGN(new_limit, HPAGE_SIZE); if (kvm->arch.mem_limit != KVM_S390_NO_MEM_LIMIT && new_limit > kvm->arch.mem_limit) -- 2.54.0