RedHat 5.4 Xen has SR-IOV support for the 82576, however there are some kernel issues that make performance slow. Release 5.5 fixed these and added support for the 82599 - however an important patch was missing, so a zstream release to 5.5 fixed this.
SR-IOV is a technology that requires support from pretty much everything including BIOS, platform (chipset), VMM and NIC. Red Hat does not have SR-IOV support in 5.3.
I have a SR-IOV primer document you may find useful for some background information: http://download.intel.com/design/network/applnots/321211.pdf
and another BLOG discussing how to setup SR-IOV in RH 5.4: http://communities.intel.com/community/wired/blog/2010/03/01/setting-up-red-hat-54-xen-for-sr-iov-using-the-intel-82576-gbe
Hi, now I am doing test about sr-iov. I can setup vfs using 82576 and pass it to VMs. However, when I change it to 82599, no VF appears any more. If I use "dmesg" to see what happens, it displays "not enough MMIO resource for SR-IOV" , first ,we think that it may be caused by the OS, but we have tried several OS including Centos 5.4(i386 and X64),5.6, REDHAT 5.5,5.6 and the problem remains.Now we really don't know what's the problem.Thanks very much!