From patchwork Mon Mar 6 13:17:55 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 9606071 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 499576046A for ; Mon, 6 Mar 2017 13:44:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3918B2723E for ; Mon, 6 Mar 2017 13:44:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2C0BF28418; Mon, 6 Mar 2017 13:44:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9E6122723E for ; Mon, 6 Mar 2017 13:44:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753652AbdCFNo4 (ORCPT ); Mon, 6 Mar 2017 08:44:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44460 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753608AbdCFNon (ORCPT ); Mon, 6 Mar 2017 08:44:43 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (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 81995C054C25 for ; Mon, 6 Mar 2017 13:18:20 +0000 (UTC) Received: from t460s.redhat.com (ovpn-117-19.ams2.redhat.com [10.36.117.19]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v26DIHqb027978; Mon, 6 Mar 2017 08:18:19 -0500 From: David Hildenbrand To: kvm@vger.kernel.org Cc: Paolo Bonzini , rkrcmar@redhat.com, david@redhat.com Subject: [PATCH RFC 01/21] KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP Date: Mon, 6 Mar 2017 14:17:55 +0100 Message-Id: <20170306131815.12033-2-david@redhat.com> In-Reply-To: <20170306131815.12033-1-david@redhat.com> References: <20170306131815.12033-1-david@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 06 Mar 2017 13:18:20 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 c6b7aff..9cd6a34 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3077,8 +3077,11 @@ 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;