Re: [Embeddedxen-devel] [XenARM] Re:xen-pxa270-qemu

[SAMBUC L. <lio...@he...>]

Hello,

> -----Original Message-----
> From: sreenaath vasudevan [mailto:sre...@gm...]
> Sent: vendredi 23 avril 2010 04:14
> To: emb...@li...
> Subject: Re: [Embeddedxen-devel] [XenARM] Re:xen-pxa270-qemu
> 
... 
> 
> 	3. Also I changed the /etc/wemu-ifup script as follows (added two
> more lines to what is givien in the wiki for adding the bridge being
> linking it with the tap0 interface.)
> 	       /etc/qemu-ifup
> 
> 	       #!/bin/sh
> 	       BRIDGE=br0
> 	      #setup in promiscuous mode qemu's device
> 	      echo ifconfig $1 0.0.0.0 promisc up
> 	      ifconfig $1 0.0.0.0 promisc up
> 	      echo brctl addbr $BRIDGE
> 	      brctl addbr $BRIDGE
> 	      #add it to the bridge
> 	      echo brctl addif $BRIDGE $1
> 	      brctl addif $BRIDGE $1
> 

While not being a show stopper, your qemu-ifup script seems wrong, please take the one from the GettingStarted guide. Based on your email, I also updated the guide this morning as some steps where incomplete. 

For reference, the complete script:

 #!/bin/sh 
 
 BRIDGE=br0
 
 #setup in promiscuous mode qemu's device
 echo ifconfig $1 0.0.0.0 promisc up
 ifconfig $1 0.0.0.0 promisc up
 #add it to the bridge
 echo brctl addif $BRIDGE $1
 brctl addif $BRIDGE $1

The bridge device is created once (normally in /etc/network/interfaces) and then only modified with regards to the linked interfaces (brctl addif and brctl delif commands). This is also why we can see complaints about trying to create a bridge interface which already exists.

> ---------------------------------------------------------------------
> 	user@ubuntu:~/embeddedxen# sudo qemu-system-arm -localtime -M
> mainstone -kernel ./xen/arch/arm/boot/uImage.mainstone -s -m 256 -pflash
> ./flash1 -pflash ./flash2 -net nic -net tap,ifname=tap0,script=/etc/qemu-ifup
> 	ifconfig tap0 0.0.0.0 promisc up
> 	brctl addbr br0
> 	device br0 already exists; can't create bridge with the same name

This error comes from your "brctl addbr $BRIDGE" command.

> 	brctl addif br0 tap0
> 	map addr 0x82200a0
...
> 
> --
> regards
> sreenaath

Have a nice day,

Lionel