Unable to establish TCP sessions between guests using virtio-net on Linux 3.12 and above
Hello,
Kernel versions tested: 3.13, 3.14, 3.15
Related debian bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=738863
I'm not sure if this is a problem specific to openvswitch or KVM. I have a network setup where I have one openvswitch bridge setup, with various ports with VLAN tags and a firewall running as a guest. After upgrading to Linux 3.13, all guests with virtio interfaces with TSO enabled (the default) are unable to establish TCP connections via the guest firewall. ICMP ping works fine. If I disable TSO on the vnet interfaces (as outlined in the bug report above) guests are then able to communicate with each other.
Is there a patch for this issue that hasn't made it into mainline that I should test out? Is this an issue specific to KVM, or is it an openvswitch issue?
Than kyou,
-Peter
Quoted 5 lines · Peter Kieser
Hello,
Kernel versions tested: 3.13, 3.14, 3.15
Related debian bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=738863
Quoted 8 lines
I'm not sure if this is a problem specific to openvswitch or KVM. I have a network setup where I have one openvswitch bridge setup, with various ports with VLAN tags and a firewall running as a guest. After upgrading to Linux 3.13, all guests with virtio interfaces with TSO enabled (the default) are unable to establish TCP connections via the guest firewall. ICMP ping works fine. If I disable TSO on the vnet interfaces (as outlined in the bug report above) guests are then able to communicate with each other.
Is there a patch for this issue that hasn't made it into mainline that I should test out? Is this an issue specific to KVM, or is it an openvswitch issue?
Than kyou,
-Peter
Hello,
Some further testing:
* Disabling vhost-net (vhost=off) for a particular VM has no effect to this issue
* Changing from virtio to e1000 for the NIC completely resolves this issue
-Peter