From patchwork Mon Jan 23 13:59:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 9532559 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 CA2BD6042D for ; Mon, 23 Jan 2017 14:02:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B35D128364 for ; Mon, 23 Jan 2017 14:02:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A647B2836D; Mon, 23 Jan 2017 14:02:10 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6B9AC28364 for ; Mon, 23 Jan 2017 14:02:06 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cVfA5-0006wj-UZ; Mon, 23 Jan 2017 13:59:57 +0000 Received: from mail6.bemta6.messagelabs.com ([193.109.254.103]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cVfA4-0006ue-Ow for xen-devel@lists.xenproject.org; Mon, 23 Jan 2017 13:59:56 +0000 Received: from [193.109.254.147] by server-6.bemta-6.messagelabs.com id B0/62-15112-C5C06885; Mon, 23 Jan 2017 13:59:56 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpkkeJIrShJLcpLzFFi42JxWrrBXjeapy3 CYOJ2FYvvWyYzOTB6HP5whSWAMYo1My8pvyKBNaNzcVLBAsmKf+9iGxhvi3QxcnJICPhL7P29 ggnEZhPQkZj69BJrFyMHh4iAisTtvQYgYWYBb4kDO1vZQGxhoPLt/3eAlbMIqEp8mL2cHaScV 8BNYv89VoiJchLnj/9kBrE5Bdwluhc/ZQGxhYBKNl5eDGWrSKyfOgtsJK+AoMTJmU9YIFZJSB x88YJ5AiPvLCSpWUhSCxiZVjFqFKcWlaUW6RoZ6CUVZaZnlOQmZuboGhqY6eWmFhcnpqfmJCY V6yXn525iBAYNAxDsYPy1LOAQoyQHk5Io7434lgghvqT8lMqMxOKM+KLSnNTiQ4wyHBxKErxX udsihASLUtNTK9Iyc4DhC5OW4OBREuFVA0nzFhck5hZnpkOkTjEqSonzVoIkBEASGaV5cG2wm LnEKCslzMsIdIgQT0FqUW5mCar8K0ZxDkYlYV5TkCk8mXklcNNfAS1mAlosK9EMsrgkESEl1c DowaLUd9ja4qzuqYZgjd4+wfCE3SHfJu3X3L7Jc9Oxyi/fP0v0nWA6N5dzb5diQ3jl14a660u +FByy2vQ+MujTUUPD2FWFJ1InpCW0ffBU/GEYPXf+/10xradzU9+9tXJYNN+YrfK/X4iw6wUj d4Ed26Z4/rjLbGZ/Sbh1vs7dl/Hdd5YqLXijxFKckWioxVxUnAgAiwP3ZZQCAAA= X-Env-Sender: prvs=189c79d20=Paul.Durrant@citrix.com X-Msg-Ref: server-12.tower-27.messagelabs.com!1485179992!81803936!3 X-Originating-IP: [66.165.176.63] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni42MyA9PiAzMDYwNDg=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 9.1.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 47677 invoked from network); 23 Jan 2017 13:59:55 -0000 Received: from smtp02.citrix.com (HELO SMTP02.CITRIX.COM) (66.165.176.63) by server-12.tower-27.messagelabs.com with RC4-SHA encrypted SMTP; 23 Jan 2017 13:59:55 -0000 X-IronPort-AV: E=Sophos;i="5.33,274,1477958400"; d="scan'208";a="410209778" From: Paul Durrant To: Date: Mon, 23 Jan 2017 13:59:49 +0000 Message-ID: <1485179989-1763-9-git-send-email-paul.durrant@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1485179989-1763-1-git-send-email-paul.durrant@citrix.com> References: <1485179989-1763-1-git-send-email-paul.durrant@citrix.com> MIME-Version: 1.0 Cc: Paul Durrant , Jan Beulich Subject: [Xen-devel] [PATCH v7 8/8] x86/hvm: serialize trap injecting producer and consumer X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP Since injection works on a remote vCPU, and since there's no enforcement of the subject vCPU being paused, there's a potential race between the producing and consuming sides. Fix this by leveraging the vector field as synchronization variable. Signed-off-by: Jan Beulich [re-based] Signed-off-by: Paul Durrant Reviewed-by: Andrew Cooper --- v6: - Adjust naming as required by previous patch. v3: - Re-re-re-based after more changes. v2: - Re-re-based after Andrew's recent changes. --- xen/arch/x86/hvm/dm.c | 5 ++++- xen/arch/x86/hvm/hvm.c | 10 ++++++---- xen/include/asm-x86/hvm/hvm.h | 3 +++ 3 files changed, 13 insertions(+), 5 deletions(-) diff --git a/xen/arch/x86/hvm/dm.c b/xen/arch/x86/hvm/dm.c index ba88766..60cd602 100644 --- a/xen/arch/x86/hvm/dm.c +++ b/xen/arch/x86/hvm/dm.c @@ -245,13 +245,16 @@ static int inject_event(struct domain *d, if ( data->vcpuid >= d->max_vcpus || !(v = d->vcpu[data->vcpuid]) ) return -EINVAL; - if ( v->arch.hvm_vcpu.inject_event.vector != -1 ) + if ( cmpxchg(&v->arch.hvm_vcpu.inject_event.vector, + HVM_EVENT_VECTOR_UNSET, HVM_EVENT_VECTOR_UPDATING) != + HVM_EVENT_VECTOR_UNSET ) return -EBUSY; v->arch.hvm_vcpu.inject_event.type = data->type; v->arch.hvm_vcpu.inject_event.insn_len = data->insn_len; v->arch.hvm_vcpu.inject_event.error_code = data->error_code; v->arch.hvm_vcpu.inject_event.cr2 = data->cr2; + smp_wmb(); v->arch.hvm_vcpu.inject_event.vector = data->vector; return 0; diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index dc8af05..0ff81d7 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -538,13 +538,15 @@ void hvm_do_resume(struct vcpu *v) } } - /* Inject pending hw/sw trap */ - if ( v->arch.hvm_vcpu.inject_event.vector != -1 ) + /* Inject pending hw/sw event */ + if ( v->arch.hvm_vcpu.inject_event.vector >= 0 ) { + smp_rmb(); + if ( !hvm_event_pending(v) ) hvm_inject_event(&v->arch.hvm_vcpu.inject_event); - v->arch.hvm_vcpu.inject_event.vector = -1; + v->arch.hvm_vcpu.inject_event.vector = HVM_EVENT_VECTOR_UNSET; } if ( unlikely(v->arch.vm_event) && v->arch.monitor.next_interrupt_enabled ) @@ -1515,7 +1517,7 @@ int hvm_vcpu_initialise(struct vcpu *v) (void(*)(unsigned long))hvm_assert_evtchn_irq, (unsigned long)v); - v->arch.hvm_vcpu.inject_event.vector = -1; + v->arch.hvm_vcpu.inject_event.vector = HVM_EVENT_VECTOR_UNSET; if ( is_pvh_domain(d) ) { diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h index 04e67fe..f88ff2e 100644 --- a/xen/include/asm-x86/hvm/hvm.h +++ b/xen/include/asm-x86/hvm/hvm.h @@ -77,6 +77,9 @@ enum hvm_intblk { #define HVM_HAP_SUPERPAGE_2MB 0x00000001 #define HVM_HAP_SUPERPAGE_1GB 0x00000002 +#define HVM_EVENT_VECTOR_UNSET (-1) +#define HVM_EVENT_VECTOR_UPDATING (-2) + /* * The hardware virtual machine (HVM) interface abstracts away from the * x86/x86_64 CPU virtualization assist specifics. Currently this interface