IB/hfi: Only read capability registers if the capability exists

commit 4c009af473 upstream.

During driver init, various registers are saved to allow restoration
after an FLR or gen3 bump.  Some of these registers are not available
in some circumstances (i.e. Virtual machines).

This bug makes the driver unusable when the PCI device is passed into
a VM, it fails during probe.

Delete unnecessary register read/write, and only access register if
the capability exists.

Fixes: a618b7e40a ("IB/hfi1: Move saving PCI values to a separate function")
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael J. Ruhl 2017-12-22 08:47:20 -08:00 • committed by Greg Kroah-Hartman
commit 907145e68e
2 changed files with 12 additions and 19 deletions