From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: [PATCH v1 01/22] KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP Date: Tue, 14 Mar 2017 14:34:29 +0100 Message-ID: <20170314133450.13259-2-david@redhat.com> References: <20170314133450.13259-1-david@redhat.com> Cc: Paolo Bonzini , rkrcmar@redhat.com, david@redhat.com To: kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44006 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751217AbdCNNez (ORCPT ); Tue, 14 Mar 2017 09:34:55 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D78CC83F3E for ; Tue, 14 Mar 2017 13:34:55 +0000 (UTC) In-Reply-To: <20170314133450.13259-1-david@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avoid races between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP by taking the kvm->lock when setting up routes. If KVM_CREATE_IRQCHIP fails, KVM_SET_GSI_ROUTING could have already set up routes pointing at pic/ioapic, being silently removed already. Signed-off-by: David Hildenbrand --- virt/kvm/kvm_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a17d787..ad0f8b2 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3079,8 +3079,11 @@ static long kvm_vm_ioctl(struct file *filp, routing.nr * sizeof(*entries))) goto out_free_irq_routing; } + /* avoid races with KVM_CREATE_IRQCHIP on x86 */ + mutex_lock(&kvm->lock); r = kvm_set_irq_routing(kvm, entries, routing.nr, routing.flags); + mutex_unlock(&kvm->lock); out_free_irq_routing: vfree(entries); break; -- 2.9.3