x86/PCI: config space accessor functions should not ignore the segment argument
Without this change, the majority of the raw PCI config space access
functions silently ignore a non-zero segment argument, which is
certainly wrong.
Apart from pci_direct_conf1, all other non-MMCFG access methods get
used only for non-extended accesses (i.e. assigned to raw_pci_ops
only). Consequently, with the way raw_pci_{read,write}() work, it would
be a coding error to call these functions with a non-zero segment (with
the current call flow this cannot happen afaict).
The access method 1 accessor, as it can be used for extended accesses
(on AMD systems) instead gets checks added for the passed in segment to
be zero. This would be the case when on such a system having multiple
PCI segments (don't know whether any exist in practice) MMCFG for some
reason is not usable, and method 1 gets selected for doing extended
accesses. Rather than accessing the wrong device's config space, the
function will now error out.
v2: Convert BUG_ON() to WARN_ON(), and extend description as per Ingo's
request.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/arch/x86/pci/olpc.c b/arch/x86/pci/olpc.c
index 13700ec..5262603 100644
--- a/arch/x86/pci/olpc.c
+++ b/arch/x86/pci/olpc.c
@@ -206,6 +206,8 @@
{
uint32_t *addr;
+ WARN_ON(seg);
+
/* Use the hardware mechanism for non-simulated devices */
if (!is_simulated(bus, devfn))
return pci_direct_conf1.read(seg, bus, devfn, reg, len, value);
@@ -264,6 +266,8 @@
static int pci_olpc_write(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, uint32_t value)
{
+ WARN_ON(seg);
+
/* Use the hardware mechanism for non-simulated devices */
if (!is_simulated(bus, devfn))
return pci_direct_conf1.write(seg, bus, devfn, reg, len, value);