Commit 864d296c authored by Chris Wright's avatar Chris Wright Committed by Jesse Barnes

PCI: ARI is a PCIe v2 feature

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.

Cc: stable@kernel.org
Acked-by: default avatarDon Dutile <ddutile@redhat.com>
Tested-by: default avatarDon Dutile <ddutile@redhat.com>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent a8c7ef31
...@@ -1905,7 +1905,7 @@ void pci_enable_ari(struct pci_dev *dev) ...@@ -1905,7 +1905,7 @@ void pci_enable_ari(struct pci_dev *dev)
{ {
int pos; int pos;
u32 cap; u32 cap;
u16 ctrl; u16 flags, ctrl;
struct pci_dev *bridge; struct pci_dev *bridge;
if (!pci_is_pcie(dev) || dev->devfn) if (!pci_is_pcie(dev) || dev->devfn)
...@@ -1923,6 +1923,11 @@ void pci_enable_ari(struct pci_dev *dev) ...@@ -1923,6 +1923,11 @@ void pci_enable_ari(struct pci_dev *dev)
if (!pos) if (!pos)
return; 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); pci_read_config_dword(bridge, pos + PCI_EXP_DEVCAP2, &cap);
if (!(cap & PCI_EXP_DEVCAP2_ARI)) if (!(cap & PCI_EXP_DEVCAP2_ARI))
return; return;
......
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