Hi, This is a qemu-kvm (i.e. not qemu) bug report. I've been told on IRC (#kvm) that this bug report should go to this list anyway.
host and guest kernel: 2.6.32.22 arch: amd64 qemu-kvm: 0.12.5 and 0.13.0-rc1 How to reproduce: copy a large (few hundred MB) file to an NFS mount (guest is the client), using qdev syntax for virtio: -device virtio-net-pci,netdev=tap1,mac=ab:cd:ef:01:23:45 \ -netdev type=tap,id=tap1,ifname=tap1 all NFS mounts immediately stall and processes go into D state and are stuck on nfs_wait_bit_uninterruptible. There is no further communication between the client and the server. It occurs with UDP and TCP mounts. That same guest, when switched to the old -net/-net syntax: -net nic,vlan=0,model=virtio,name=eth0,macaddr=ab:cd:ef:01:23:45 \ -net tap,vlan=0,ifname=tap1 works fine. It also works fine on bare metal. I can reproduce the problem every time within 10 minutes with qdev. -- Leszek "Tygrys" Urbanski, SCSA, SCNA "Unix-to-Unix Copy Program;" said PDP-1. "You will never find a more wretched hive of bugs and flamers. We must be cautious." -- DECWARS http://cygnus.moo.pl/ -- Cygnus High Altitude Balloon