Summary: KVM Guest with virtio network driver loses network
           Product: Virtualization
           Version: unspecified
    Kernel Version: 3.3.0-rc5
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: kvm
        Regression: Yes

Running KVM guests with virtio network interfaces, the guest will
(probably in some - unidentified - circumstances) stop receiving packets.
A tcpdump on the bugged interface will show only ARP requests being
sent by the server and unanswered.

Possible workarounds:

- restart network interface in guest

- use e1000 network driver as replacement of virtio_net driver

How to reproduce:
1) start KVM guest:
-name vps
-chroot /chroot
-runas kvm
-pidfile /var/run/kvm/
-vga std --full-screen
-smp 2 -m 1g -cpu host
-mem-path /hugepages
-kvm-shadow-memory 1g
-rtc base=localtime,clock=host,driftfix=none
-balloon virtio
-net nic,model=virtio,vlan=0,macaddr=52:54:00:33:22:11
-net bridge,br=br0,vlan=0
-drive aio=native,index=0,media=disk,cache=none,if=virtio,file=vps.img
-boot order=c,menu=off &

2) generate huge trafic (after few minutes virtio network card crashed):
 from host to guest:
  screen ping -s 65507
  screen iperf -s -i 1 -f M
 from guest to host:
  screen ping -s 65507
  screen iperf -c -i 1 -f M

3) restart guest network interface and repeat step 2) until network crash again

Above situation occurs on (my tests):
host kernel 3.3+
qemu-kvm 1.0+
any guest Linux 2.6+ - 3.3+ kernel
any guest Windows 7+

Same situation described from other users on some forums:
(possible, not tested old patch)

Please fix above crashing of virtio_net driver.

Thank you for your time.

Configure bugmail:
------- You are receiving this mail because: -------
You are watching the assignee of the bug.
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to
More majordomo info at

Reply via email to