Linux Virtualization - Dec 2007 - [Virtio-for-kvm] [PATCH 5/7] userspace virtio

From 35a03164c1b4d138e55898853212bded14cf4ec7 Mon Sep 17 00:00:00 2001
From: Dor Laor <dor.laor@qumranet.com>
Date: Mon, 17 Dec 2007 01:43:28 +0200
Subject: [PATCH] Check for device status on tx.

Allow tx only if VIRTIO_CONFIG_S_DRIVER_OK.
It can prevent an smp race of tx and driver unload.

Signed-off-by: Dor Laor <dor.laor@qumranet.com>
---
 qemu/hw/virtio-net.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/qemu/hw/virtio-net.c b/qemu/hw/virtio-net.c
index 3320dd8..f6f1f28 100644
--- a/qemu/hw/virtio-net.c
+++ b/qemu/hw/virtio-net.c
@@ -140,6 +140,9 @@ static void virtio_net_handle_tx(VirtIODevice *vdev, 
VirtQueue *vq)
     VirtIONet *n = to_virtio_net(vdev);
     VirtQueueElement elem;
 
+    if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
+        return;
+
     while (virtqueue_pop(vq, &elem)) {
     int i;
     size_t len = 0;
-- 
1.5.3.3