Export the helper to retrieve supported PCIe TPH steering tag modes so that drivers like VFIO can query and expose device capabilities to userspace. Add stub functions for pcie_tph_get_st_table_size() and pcie_tph_get_st_table_loc() when !CONFIG_PCI_TPH. Add tph_cap validation for pcie_tph_get_st_modes() and pcie_tph_get_st_table_loc() to prevent invalid PCI configuration space access when TPH is not supported. Signed-off-by: Chengwen Feng Acked-by: Bjorn Helgaas --- drivers/pci/tph.c | 20 ++++++++++++++++++-- include/linux/pci-tph.h | 7 +++++++ 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/drivers/pci/tph.c b/drivers/pci/tph.c index f17b74b5fb1e..ba31b010f67a 100644 --- a/drivers/pci/tph.c +++ b/drivers/pci/tph.c @@ -145,15 +145,27 @@ static void set_ctrl_reg_req_en(struct pci_dev *pdev, u8 req_type) pci_write_config_dword(pdev, pdev->tph_cap + PCI_TPH_CTRL, reg); } -static u8 get_st_modes(struct pci_dev *pdev) +/** + * pcie_tph_get_st_modes - Get supported Steering Tag modes + * @pdev: PCI device to query + * + * Return: + * Bitmask of supported ST modes (PCI_TPH_CAP_ST_NS, PCI_TPH_CAP_ST_IV, + * PCI_TPH_CAP_ST_DS) + */ +u8 pcie_tph_get_st_modes(struct pci_dev *pdev) { u32 reg; + if (!pdev->tph_cap) + return 0; + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CAP, ®); reg &= PCI_TPH_CAP_ST_NS | PCI_TPH_CAP_ST_IV | PCI_TPH_CAP_ST_DS; return reg; } +EXPORT_SYMBOL(pcie_tph_get_st_modes); /** * pcie_tph_get_st_table_loc - Return the device's ST table location @@ -168,6 +180,9 @@ u32 pcie_tph_get_st_table_loc(struct pci_dev *pdev) { u32 reg; + if (!pdev->tph_cap) + return PCI_TPH_LOC_NONE; + pci_read_config_dword(pdev, pdev->tph_cap + PCI_TPH_CAP, ®); return reg & PCI_TPH_CAP_LOC_MASK; @@ -183,6 +198,7 @@ u16 pcie_tph_get_st_table_size(struct pci_dev *pdev) u32 reg; u32 loc; + /* Check ST table location first */ loc = pcie_tph_get_st_table_loc(pdev); if (loc != PCI_TPH_LOC_CAP) return 0; @@ -394,7 +410,7 @@ int pcie_enable_tph(struct pci_dev *pdev, int mode) /* Sanitize and check ST mode compatibility */ mode &= PCI_TPH_CTRL_MODE_SEL_MASK; - dev_modes = get_st_modes(pdev); + dev_modes = pcie_tph_get_st_modes(pdev); if (!((1 << mode) & dev_modes)) return -EINVAL; diff --git a/include/linux/pci-tph.h b/include/linux/pci-tph.h index be68cd17f2f8..586c75b19e01 100644 --- a/include/linux/pci-tph.h +++ b/include/linux/pci-tph.h @@ -30,6 +30,7 @@ void pcie_disable_tph(struct pci_dev *pdev); int pcie_enable_tph(struct pci_dev *pdev, int mode); u16 pcie_tph_get_st_table_size(struct pci_dev *pdev); u32 pcie_tph_get_st_table_loc(struct pci_dev *pdev); +u8 pcie_tph_get_st_modes(struct pci_dev *pdev); #else static inline int pcie_tph_set_st_entry(struct pci_dev *pdev, unsigned int index, u16 tag) @@ -41,6 +42,12 @@ static inline int pcie_tph_get_cpu_st(struct pci_dev *dev, static inline void pcie_disable_tph(struct pci_dev *pdev) { } static inline int pcie_enable_tph(struct pci_dev *pdev, int mode) { return -EINVAL; } +static inline u16 pcie_tph_get_st_table_size(struct pci_dev *pdev) +{ return 0; } +static inline u32 pcie_tph_get_st_table_loc(struct pci_dev *pdev) +{ return 0x7FF; /* Values that do not appear in normal case */ } +static inline u8 pcie_tph_get_st_modes(struct pci_dev *pdev) +{ return 0; } #endif #endif /* LINUX_PCI_TPH_H */ -- 2.17.1