Messages in this thread Patch in this message | | | Date | Fri, 05 Aug 2011 17:02:02 -0700 | From | Greg KH <> | Subject | [32/55] PCI: ARI is a PCIe v2 feature |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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From: Chris Wright <chrisw@sous-sol.org>
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>
--- drivers/pci/pci.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- 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;
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