Re: Intel Quad NIC always wants a reboot for passthrough
I found the answer after seeing the following message in /var/log/vmkernel.log:2011-11-04T19:35:32.913Z cpu0:2626)WARNING: PCI: 3557: 000:006:00.0: Cannot change ownership to PASSTHRU (non-ACS capable switch in hierarchy)
It appears that a PCI-e switch on the quad NIC does not support Access Control Services. VMware KB article 1036811, http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1036811
, says:Access Control Services (ACS) was introduced by the PCI-SIG to address potential data corruption with direct assignment of devices. Passthrough of a PCIe device to a virtual machine, using DirectPath I/O, is disallowed by the VMKernel if the device is connected to a switch that does not support Access Control Services.