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| author | Chris Wright <chrisw@sous-sol.org> | 2011-07-13 10:14:33 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-08 10:35:59 -0700 |
| commit | eed4a1ebe22299f6120d3ca267bb21585be73703 (patch) | |
| tree | 04b87736b7952eb8b2d6cd2975ee05287ad9d838 | |
| parent | c3f379d612a3ef1d1158a7afaab16758a222bc73 (diff) | |
| download | lwn-eed4a1ebe22299f6120d3ca267bb21585be73703.tar.gz lwn-eed4a1ebe22299f6120d3ca267bb21585be73703.zip | |
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>
| -rw-r--r-- | drivers/pci/pci.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b8eb5e77df8b..5e251028db91 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1528,7 +1528,7 @@ void pci_enable_ari(struct pci_dev *dev) { int pos; u32 cap; - u16 ctrl; + u16 flags, ctrl; struct pci_dev *bridge; if (!pci_is_pcie(dev) || dev->devfn) @@ -1546,6 +1546,11 @@ 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; |