From patchwork Sat Mar 7 19:06:56 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 5960101 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 37C4EBF440 for ; Sat, 7 Mar 2015 19:07:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6FE6D201FE for ; Sat, 7 Mar 2015 19:07:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 942F82011D for ; Sat, 7 Mar 2015 19:07:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751855AbbCGTHI (ORCPT ); Sat, 7 Mar 2015 14:07:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35918 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751628AbbCGTHH (ORCPT ); Sat, 7 Mar 2015 14:07:07 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t27J6xXK012321 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Sat, 7 Mar 2015 14:07:00 -0500 Received: from redhat.com (ovpn-116-20.ams2.redhat.com [10.36.116.20]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id t27J6uf7015236; Sat, 7 Mar 2015 14:06:57 -0500 Date: Sat, 7 Mar 2015 20:06:56 +0100 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, Rusty Russell , kvm@vger.kernel.org, qemu-devel@nongnu.org, Ohad Ben-Cohen Subject: [PATCH] virtio_rpmsg: set DRIVER_OK before using device Message-ID: <1425754898-32707-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP virtio spec requires that all drivers set DRIVER_OK before using devices. While rpmsg isn't yet included in the virtio 1 spec, previous spec versions also required this. virtio rpmsg violates this rule: is calls kick before setting DRIVER_OK. The fix isn't trivial since simply calling virtio_device_ready earlier would mean we might get an interrupt in parallel with adding buffers. Instead, split kick out to prepare+notify calls. prepare before virtio_device_ready - when we know we won't get interrupts. notify right afterwards. Signed-off-by: Michael S. Tsirkin Acked-by: Ohad Ben-Cohen --- Note: compile-tested only. drivers/rpmsg/virtio_rpmsg_bus.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c index 92f6af6..73354ee 100644 --- a/drivers/rpmsg/virtio_rpmsg_bus.c +++ b/drivers/rpmsg/virtio_rpmsg_bus.c @@ -951,6 +951,7 @@ static int rpmsg_probe(struct virtio_device *vdev) void *bufs_va; int err = 0, i; size_t total_buf_space; + bool notify; vrp = kzalloc(sizeof(*vrp), GFP_KERNEL); if (!vrp) @@ -1030,8 +1031,22 @@ static int rpmsg_probe(struct virtio_device *vdev) } } + /* + * Prepare to kick but don't notify yet - we can't do this before + * device is ready. + */ + notify = virtqueue_kick_prepare(vrp->rvq); + + /* From this point on, we can notify and get callbacks. */ + virtio_device_ready(vdev); + /* tell the remote processor it can start sending messages */ - virtqueue_kick(vrp->rvq); + /* + * this might be concurrent with callbacks, but we are only + * doing notify, not a full kick here, so that's ok. + */ + if (notify) + virtqueue_notify(vrp->rvq); dev_info(&vdev->dev, "rpmsg host is online\n");