Need help debugging virtio net issue

[Darren Dao <darrendao@xxxxxxxxx>]

This is what I use for creating the VM

sudo virt-install -n myvm -r 2048 --vcpus=1 --accelerate -v -w bridge:br0,model=virtio  --nographics -m 54:52:00:01:bb:8d  --disk path=/storage_pool/myvm.raw,size=20,bus=virtio --pxe

It used to work fine, but now it get stuck trying to do pxeboot/kickstart. Here's what I see when trying to debug the pxeboot/kickstart process:

* Querying DHCP server for IP address went through fine

* vmlinuz.CentOS5-5.5-x86_64 was downloaded successfully

* initrd.img.CentOS5-5.5-x86_64 started to get transferred, but then stopped. It looks like the VM's network interface just crashed (can't even ping the VM anymore)

If I don't use virtio for networking, then everything went through fine.

What's strange that is virtio used to work fine. 

I ran out of ideas/ways to debug this issue. Any has any idea?

Here's more info on my system:

Host:

   * Scientific Linux 6, kernel version: 2.6.32-71.el6.x86_64

   * libvirt: 0.8.1-27

   * qemu-kvm: 0.12.1.2-2.113

 Guest:

   * Scientific Linux 6, kernel version: 2.6.32-71.el6.x86_64