From patchwork Mon Jul 2 06:31:39 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pankaj Gupta X-Patchwork-Id: 10500537 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 E912C6035E for ; Mon, 2 Jul 2018 06:32:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D939128742 for ; Mon, 2 Jul 2018 06:32:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CC68F28749; Mon, 2 Jul 2018 06:32:36 +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=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 659B928742 for ; Mon, 2 Jul 2018 06:32:36 +0000 (UTC) Received: from localhost ([::1]:57225 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fZsO3-0000dJ-4M for patchwork-qemu-devel@patchwork.kernel.org; Mon, 02 Jul 2018 02:32:35 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35904) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fZsNN-0000It-W2 for qemu-devel@nongnu.org; Mon, 02 Jul 2018 02:31:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fZsNJ-0006zx-WD for qemu-devel@nongnu.org; Mon, 02 Jul 2018 02:31:54 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55940 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fZsNJ-0006yE-RP for qemu-devel@nongnu.org; Mon, 02 Jul 2018 02:31:49 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E9CAA7CBBA; Mon, 2 Jul 2018 06:31:48 +0000 (UTC) Received: from dhcp201-121.englab.pnq.redhat.com (dhcp193-70.pnq.redhat.com [10.65.193.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id E07D6111DCF6; Mon, 2 Jul 2018 06:31:42 +0000 (UTC) From: Pankaj Gupta To: mst@redhat.com, amit@kernel.org, qemu-devel@nongnu.org Date: Mon, 2 Jul 2018 12:01:39 +0530 Message-Id: <20180702063139.7935-1-pagupta@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 02 Jul 2018 06:31:48 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 02 Jul 2018 06:31:48 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'pagupta@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v3] virtio-rng: process pending requests when driver is ready X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: slopezpa@redhat.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP virtio-rng device causing old guest kernels(2.6.32) to hang on latest qemu. The driver attempts to read from the virtio-rng device too early in it's initialization. Qemu detects guest is not ready and returns, resulting in hang. Fix is to handle pending request when guest is running and driver status is set to 'VIRTIO_CONFIG_S_DRIVER_OK'. Signed-off-by: Pankaj Gupta --- v2->v3: Add comment to explain virtio-rng early status update (Stefan) v1->v2: Update new status value early only for virtio-rng (Stefan) hw/virtio/virtio-rng.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c index 289bbcac03..0b586bd750 100644 --- a/hw/virtio/virtio-rng.c +++ b/hw/virtio/virtio-rng.c @@ -156,6 +156,24 @@ static void check_rate_limit(void *opaque) vrng->activate_timer = true; } +static void virtio_rng_set_status(VirtIODevice *vdev, uint8_t status) +{ + VirtIORNG *vrng = VIRTIO_RNG(vdev); + + if (!vdev->vm_running) { + return; + } + /* Set device status in VirtIODevice object. Its used in 'is_guest_ready' + * function to check if guest is ready and process the pending requests. + * Other virtio devices might be dependent on old value of status, so + * update status early only for virtio-rng. + */ + vdev->status = status; + + /* Something changed, try to process buffers */ + virtio_rng_process(vrng); +} + static void virtio_rng_device_realize(DeviceState *dev, Error **errp) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); @@ -261,6 +279,7 @@ static void virtio_rng_class_init(ObjectClass *klass, void *data) vdc->realize = virtio_rng_device_realize; vdc->unrealize = virtio_rng_device_unrealize; vdc->get_features = get_features; + vdc->set_status = virtio_rng_set_status; } static const TypeInfo virtio_rng_info = {