[Qemu-stable] [PATCH 3/7] tap: forbid creating multiqueue tap when hub is used

[Stefan Hajnoczi]

From: Jason Wang <address@hidden>

Obviously, hub does not support multiqueue tap. So this patch forbids creating
multiple queue tap when hub is used to prevent the crash when command line such
as "-net tap,queues=2" is used.

Cc: address@hidden
Signed-off-by: Jason Wang <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
 net/tap.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/tap.c b/net/tap.c
index 48c254e..daab350 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -693,6 +693,13 @@ int net_init_tap(const NetClientOptions *opts, const char 
*name,
     queues = tap->has_queues ? tap->queues : 1;
     vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
 
+    /* QEMU vlans does not support multiqueue tap, in this case peer is set.
+     * For -netdev, peer is always NULL. */
+    if (peer && (tap->has_queues || tap->has_fds || tap->has_vhostfds)) {
+        error_report("Multiqueue tap cannnot be used with QEMU vlans");
+        return -1;
+    }
+
     if (tap->has_fd) {
         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
-- 
1.8.1.2