Bug 202517

Summary: PCI PF memory decode disable when sizing VF BARs
Product: Base System Reporter: Eric Badger <eric>
Component: kernAssignee: freebsd-bugs (Nobody) <bugs>
Status: New ---    
Severity: Affects Some People CC: rstone, vangyzen
Priority: --- Keywords: patch
Version: CURRENT   
Hardware: amd64   
OS: Any   
Attachments:
Description Flags
Patch to prevent disabling of PF during VF bar sizing none

Description Eric Badger 2015-08-20 13:18:36 UTC
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:
https://lists.freebsd.org/pipermail/freebsd-current/2015-May/055725.html

I've been using the attached patch (from the above thread) for some time to solve this problem.