Latest working kernel version: 2.6.21.7-5.fc8xen.x86_64
Earliest failing kernel version: 2.6.27.7-134.fc10.x86_64 (didn't yet try F9)
Distribution: Fedora
Hardware/Software Environment: Xen host is CentOS 5.2

Problem Description:

With Xen dom0 physical, bridge and vif interface all set to 9000-byte MTUs, I
expect to be able to set the domU eth0 MTU to 9000-bytes and enjoy a happy
jumbo-frame life.

This works on the old-style Xen guest kernels (CentOS 5.2 and Fedora 8).

I don't know about Fedora 9, but the pv_ops unified Fedora 10 kernel will work if I configure the MTU on eth0 <= 4064 bytes, but at >= 4065 bytes large packets
seem to be silently dropped somewhere.

Steps to reproduce:

"yum clean all; yum upgrade" will provoke a large rx frame--it just stiffs until I lower the MTU.

Only tried on x86_64.