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authorChris Wright <chrisw@sous-sol.org>2011-07-13 10:14:33 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:23:12 -0700
commit330091175005731845c82ae2b44ac72a93902a25 (patch)
tree3e46b0589ac469f6bd5ca1008a9c1d08ab69731c /drivers
parent1b7fbaab701bfcc77916896bf64af9624c0b62d4 (diff)
downloadlinux-linaro-stable-330091175005731845c82ae2b44ac72a93902a25.tar.gz
PCI: ARI is a PCIe v2 feature
commit 864d296cf948aef0fa32b81407541572583f7572 upstream. The function pci_enable_ari() may mistakenly set the downstream port of a v1 PCIe switch in ARI Forwarding mode. This is a PCIe v2 feature, and with an SR-IOV device on that switch port believing the switch above is ARI capable it may attempt to use functions 8-255, translating into invalid (non-zero) device numbers for that bus. This has been seen to cause Completion Timeouts and general misbehaviour including hangs and panics. Acked-by: Don Dutile <ddutile@redhat.com> Tested-by: Don Dutile <ddutile@redhat.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pci.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0d3326ddd5c1..6f8352c42d3e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1507,7 +1507,7 @@ void pci_enable_ari(struct pci_dev *dev)
{
int pos;
u32 cap;
- u16 ctrl;
+ u16 flags, ctrl;
struct pci_dev *bridge;
if (!dev->is_pcie || dev->devfn)
@@ -1525,6 +1525,11 @@ void pci_enable_ari(struct pci_dev *dev)
if (!pos)
return;
+ /* ARI is a PCIe v2 feature */
+ pci_read_config_word(bridge, pos + PCI_EXP_FLAGS, &flags);
+ if ((flags & PCI_EXP_FLAGS_VERS) < 2)
+ return;
+
pci_read_config_dword(bridge, pos + PCI_EXP_DEVCAP2, &cap);
if (!(cap & PCI_EXP_DEVCAP2_ARI))
return;