PCI: Disable IO/MEM decoding for devices with non-compliant BARs
authorBjorn Helgaas <bhelgaas@google.com>
Thu, 25 Feb 2016 20:35:57 +0000 (14:35 -0600)
committerSasha Levin <sasha.levin@oracle.com>
Mon, 18 Apr 2016 12:50:40 +0000 (08:50 -0400)
commitaa57ba13f44426a076ac567e965654453d4be1f1
tree4e7c08f27c0369f03071480738d706b7d73b2e74
parent517a021fdba44206722c85bd9267dabd67475fa6
PCI: Disable IO/MEM decoding for devices with non-compliant BARs

[ Upstream commit b84106b4e2290c081cdab521fa832596cdfea246 ]

The PCI config header (first 64 bytes of each device's config space) is
defined by the PCI spec so generic software can identify the device and
manage its usage of I/O, memory, and IRQ resources.

Some non-spec-compliant devices put registers other than BARs where the
BARs should be.  When the PCI core sizes these "BARs", the reads and writes
it does may have unwanted side effects, and the "BAR" may appear to
describe non-sensical address space.

Add a flag bit to mark non-compliant devices so we don't touch their BARs.
Turn off IO/MEM decoding to prevent the devices from consuming address
space, since we can't read the BARs to find out what that address space
would be.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Andi Kleen <ak@linux.intel.com>
CC: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
drivers/pci/probe.c
include/linux/pci.h