From: Leon Romanovsky leonro@nvidia.com
pci_acs_flags_enabled() and the Intel SPT PCH quirk use ACS registers without checking config-space read errors. A failed read may leave control state indeterminate yet allow the device to satisfy requested isolation controls.
Return false when either ACS capability or control state cannot be read. An unknown state cannot prove isolation.
Reviewed-by: Logan Gunthorpe logang@deltatee.com Tested-by: Tushar Dave tdave@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com --- drivers/pci/pci.c | 3 ++- drivers/pci/quirks.c | 6 ++++-- 2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b2879a6be5f8..f7d94ecf9157 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3594,7 +3594,8 @@ static bool pci_acs_flags_enabled(struct pci_dev *pdev, u16 acs_flags) */ acs_flags &= (pdev->acs_capabilities | PCI_ACS_EC);
- pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl); + if (pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl)) + return false; return (ctrl & acs_flags) == acs_flags; }
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index de9bbccda21f..d5c3e6802840 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -4992,10 +4992,12 @@ static int pci_quirk_intel_spt_pch_acs(struct pci_dev *dev, u16 acs_flags) return -ENOTTY;
/* see pci_acs_flags_enabled() */ - pci_read_config_dword(dev, pos + PCI_ACS_CAP, &cap); + if (pci_read_config_dword(dev, pos + PCI_ACS_CAP, &cap)) + return 0; acs_flags &= (cap | PCI_ACS_EC);
- pci_read_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, &ctrl); + if (pci_read_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, &ctrl)) + return 0;
return pci_acs_ctrl_enabled(acs_flags, ctrl); }