Created attachment 160143 [details]
Patch to prevent disabling of PF during VF bar sizing
During IOV config, when setting up VF bars, several calls are made to 'pci_read_bar' (in sys/dev/pci/pci.c) in order to size VF BARs, which causes memory decoding to be turned off temporarily for the PF associated with those VFs. This can interfere with an already running PF.
This was discussed a few months back on -current, but it doesn't look like the fix has hit the source tree:
I've been using the attached patch (from the above thread) for some time to solve this problem.