K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2019-06-05T19:29:02.063649Z
K 7
svn:log
V 1162
Don't simulate PBA access if the PBA is in a separate BAR.

bhyve has to virtualize the MSI-X table to trap reads and writes to
that table and map those to virtual interrupts that it maps real host
interrupts on to.  For the pending-bit-array (PBA), bhyve passes
accesses from the guest directly to the hardware.

bhyve's virtualization of the MSI-X table is done by intercepting all
reads and writes to the BAR holding the MSI-X table.  However, if the
PBA is stored in the same BAR as the MSI-X table, accesses to the PBA
portion of this BAR have to be forwarded to the real BAR.

However, in the case that the PBA was stored in a separate BAR and
it's offset in that separate BAR overlapped with the portion of the
MSI-X table BAR that the table used, the handlers for the table BAR
would incorrectly think that some accesses were PBA reads and writes.
This caused a crash in bhyve when it indirected a NULL pointer.  Fix
this case by never trying to handle PBA access if the PBA lives in a
separate BAR.

Reported by:	gallatin
Tested by:	gallatin
Reviewed by:	markj, Patrick Mooney
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D20523

END