From patchwork Tue Nov 22 16:31:44 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 9441521 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 E0121605EE for ; Tue, 22 Nov 2016 16:37:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D40BE285C9 for ; Tue, 22 Nov 2016 16:37:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C8933285D3; Tue, 22 Nov 2016 16:37:44 +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 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 4F28A285C9 for ; Tue, 22 Nov 2016 16:37:44 +0000 (UTC) Received: from localhost ([::1]:56569 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c9E4i-0005j7-7t for patchwork-qemu-devel@patchwork.kernel.org; Tue, 22 Nov 2016 11:37:40 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38489) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c9DzM-0001uU-HX for qemu-devel@nongnu.org; Tue, 22 Nov 2016 11:32:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c9DzL-0004FG-Gm for qemu-devel@nongnu.org; Tue, 22 Nov 2016 11:32:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41468) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c9DzL-0004Er-BL for qemu-devel@nongnu.org; Tue, 22 Nov 2016 11:32:07 -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 0CCA561E4B; Tue, 22 Nov 2016 16:32:06 +0000 (UTC) Received: from localhost (ovpn-112-53.ams2.redhat.com [10.36.112.53]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAMGW4Ca007120; Tue, 22 Nov 2016 11:32:05 -0500 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Date: Tue, 22 Nov 2016 16:31:44 +0000 Message-Id: <1479832306-26440-9-git-send-email-stefanha@redhat.com> In-Reply-To: <1479832306-26440-1-git-send-email-stefanha@redhat.com> References: <1479832306-26440-1-git-send-email-stefanha@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 [10.5.110.39]); Tue, 22 Nov 2016 16:32:06 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 08/10] virtio: turn vq->notification into a nested counter 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: borntraeger@de.ibm.com, Karl Rister , Fam Zheng , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Polling should disable virtqueue notifications but that requires nested virtio_queue_set_notification() calls. Turn vq->notification into a counter so it is possible to do nesting. Signed-off-by: Stefan Hajnoczi --- hw/virtio/virtio.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index f0ed8fe..66dd968 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -87,8 +87,8 @@ struct VirtQueue /* Last used index value we have signalled on */ bool signalled_used_valid; - /* Notification enabled? */ - bool notification; + /* Nested host->guest notification disabled counter */ + unsigned int notification_disabled; uint16_t queue_index; @@ -201,7 +201,7 @@ static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask) static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val) { hwaddr pa; - if (!vq->notification) { + if (vq->notification_disabled) { return; } pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]); @@ -210,7 +210,13 @@ static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val) void virtio_queue_set_notification(VirtQueue *vq, int enable) { - vq->notification = enable; + if (enable) { + assert(vq->notification_disabled > 0); + vq->notification_disabled--; + } else { + vq->notification_disabled++; + } + if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) { vring_set_avail_event(vq, vring_avail_idx(vq)); } else if (enable) { @@ -959,7 +965,7 @@ void virtio_reset(void *opaque) virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR); vdev->vq[i].signalled_used = 0; vdev->vq[i].signalled_used_valid = false; - vdev->vq[i].notification = true; + vdev->vq[i].notification_disabled = 0; vdev->vq[i].vring.num = vdev->vq[i].vring.num_default; vdev->vq[i].inuse = 0; } @@ -1774,7 +1780,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) vdev->vq[i].vring.desc = qemu_get_be64(f); qemu_get_be16s(f, &vdev->vq[i].last_avail_idx); vdev->vq[i].signalled_used_valid = false; - vdev->vq[i].notification = true; + vdev->vq[i].notification_disabled = 0; if (vdev->vq[i].vring.desc) { /* XXX virtio-1 devices */