KVM / Libvirtd -> bridge does not work

I am trying to get a virtual machine running with bridged networking. I am using KVM with libvirtd.

kvm/jaunty-updates uptodate 1:84+dfsg-0ubuntu12.3
libvirt-bin/jaunty-updates uptodate 0.6.1-0ubuntu5.1
qemu/jaunty uptodate 0.10.0-1ubuntu1

My host network configuration looks like this :

Code:

auto lo
iface lo inet loopback

auto br0
iface br0 inet static
	address 192.168.1.100
	netmask 255.255.255.0
	network 192.168.1.0
	broadcast 192.168.1.255
	gateway 192.168.1.1
	bridge_ports eth0
	bridge_stp off
	bridge_maxwait 5
	bridge_hello 2
	bridge_fd 9
	bridge_maxage 12

That results in :

Code:

br0       Link encap:Ethernet  HWaddr 00:24:1d:22:97:39  
          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::224:1dff:fe22:9739/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         

eth0      Link encap:Ethernet  HWaddr 00:24:1d:22:97:39  
          inet6 addr: fe80::224:1dff:fe22:9739/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          
virbr0    Link encap:Ethernet  HWaddr d6:e1:ee:be:c1:cb  
          inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0
          inet6 addr: fe80::d4e1:eeff:febe:c1cb/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

Abbreviated of course...

And just for completeness, brctl show

Code:

bridge name	bridge id		STP enabled	interfaces
br0		8000.00241d229739	no		eth0
pan0		8000.000000000000	no		
virbr0		8000.000000000000	yes

With this configuration, networking is fine, else I would not be typing here

Now, my VM instance has the following bit in it's configuration :

Code:

However, the VM can not ping the outer host, nor the gateway. I am unsure if this is relevant, but under the hardware tab -> NIC it shows "Source device" as "-". Should this not show br0 ?

Iptables in the VM is off, and iptables on my host looks like this:

Code:

Chain INPUT (policy ACCEPT 14021 packets, 18M bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     udp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           udp dpt:53 
    0     0 ACCEPT     tcp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           tcp dpt:53 
    0     0 ACCEPT     udp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           udp dpt:67 
    0     0 ACCEPT     tcp  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           tcp dpt:67 

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     all  --  *      virbr0  0.0.0.0/0            192.168.122.0/24    state RELATED,ESTABLISHED 
    0     0 ACCEPT     all  --  virbr0 *       192.168.122.0/24     0.0.0.0/0           
    0     0 ACCEPT     all  --  virbr0 virbr0  0.0.0.0/0            0.0.0.0/0           
    0     0 REJECT     all  --  *      virbr0  0.0.0.0/0            0.0.0.0/0           reject-with icmp-port-unreachable 
    0     0 REJECT     all  --  virbr0 *       0.0.0.0/0            0.0.0.0/0           reject-with icmp-port-unreachable 

Chain OUTPUT (policy ACCEPT 13739 packets, 15M bytes)
 pkts bytes target     prot opt in     out     source               destination

Those rules looks like it deals with the standard NAT.

Any help would be appreciated.