cxl: Prevent read/write to AFU config space while AFU not configured
authorAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Fri, 9 Dec 2016 06:18:50 +0000 (17:18 +1100)
committerMichael Ellerman <mpe@ellerman.id.au>
Wed, 25 Jan 2017 02:34:24 +0000 (13:34 +1100)
commit14a3ae34bfd0bcb1cc12d55b06a8584c11fac6fc
tree398be4ce65d15bb67d66e5ef12a58e42a3668537
parentd7b1946c7925a270062b2e0718aa57b42ba619c0
cxl: Prevent read/write to AFU config space while AFU not configured

During EEH recovery, we deconfigure all AFUs whilst leaving the
corresponding vPHB and virtual PCI device in place.

If something attempts to interact with the AFU's PCI config space (e.g.
running lspci) after the AFU has been deconfigured and before it's
reconfigured, cxl_pcie_{read,write}_config() will read invalid values from
the deconfigured struct cxl_afu and proceed to Oops when they try to
dereference pointers that have been set to NULL during deconfiguration.

Add a rwsem to struct cxl_afu so we can prevent interaction with config
space while the AFU is deconfigured.

Reported-by: Pradipta Ghosh <pradghos@in.ibm.com>
Suggested-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
drivers/misc/cxl/cxl.h
drivers/misc/cxl/main.c
drivers/misc/cxl/pci.c
drivers/misc/cxl/vphb.c