From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out4-smtp.messagingengine.com ([66.111.4.28]:34622 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755917AbbLGMMz (ORCPT ); Mon, 7 Dec 2015 07:12:55 -0500 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 0BB7520A21 for ; Mon, 7 Dec 2015 07:12:55 -0500 (EST) Subject: FAILED: patch "[PATCH] KVM: s390: enable SIMD only when no VCPUs were created" failed to apply to 4.2-stable tree To: dahi@linux.vnet.ibm.com, borntraeger@de.ibm.com, cornelia.huck@de.ibm.com Cc: From: Date: Sun, 06 Dec 2015 23:59:10 -0800 Message-ID: <1449475150254162@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.2-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 5967c17b118a2bd1dd1d554cc4eee16233e52bec Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 6 Nov 2015 12:08:48 +0100 Subject: [PATCH] KVM: s390: enable SIMD only when no VCPUs were created We should never allow to enable/disable any facilities for the guest when other VCPUs were already created. kvm_arch_vcpu_(load|put) relies on SIMD not changing during runtime. If somebody would create and run VCPUs and then decides to enable SIMD, undefined behaviour could be possible (e.g. vector save area not being set up). Acked-by: Christian Borntraeger Acked-by: Cornelia Huck Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger Cc: stable@vger.kernel.org # 4.1+ diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 8fe2f1c722dc..846589281b04 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -342,12 +342,16 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) r = 0; break; case KVM_CAP_S390_VECTOR_REGISTERS: - if (MACHINE_HAS_VX) { + mutex_lock(&kvm->lock); + if (atomic_read(&kvm->online_vcpus)) { + r = -EBUSY; + } else if (MACHINE_HAS_VX) { set_kvm_facility(kvm->arch.model.fac->mask, 129); set_kvm_facility(kvm->arch.model.fac->list, 129); r = 0; } else r = -EINVAL; + mutex_unlock(&kvm->lock); VM_EVENT(kvm, 3, "ENABLE: CAP_S390_VECTOR_REGISTERS %s", r ? "(not available)" : "(success)"); break;