From: Chengwen Feng <fengchengwen@huawei.com>
To: <alex@shazbot.org>, <jgg@ziepe.ca>
Cc: <wathsala.vithanage@arm.com>, <helgaas@kernel.org>,
<wei.huang2@amd.com>, <wangzhou1@hisilicon.com>,
<wangyushan12@huawei.com>, <liuyonglong@huawei.com>,
<kvm@vger.kernel.org>, <linux-pci@vger.kernel.org>
Subject: [PATCH v6 2/6] PCI/TPH: Export pcie_tph_get_st_modes() for external use
Date: Wed, 6 May 2026 17:46:19 +0800 [thread overview]
Message-ID: <20260506094623.29327-3-fengchengwen@huawei.com> (raw)
In-Reply-To: <20260506094623.29327-1-fengchengwen@huawei.com>
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 <fengchengwen@huawei.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
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
next prev parent reply other threads:[~2026-05-06 9:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-06 9:46 [PATCH v6 0/6] vfio/pci: Add PCIe TPH support Chengwen Feng
2026-05-06 9:46 ` [PATCH v6 1/6] PCI/TPH: Fix pcie_tph_get_st_table_loc() field extraction Chengwen Feng
2026-05-06 15:54 ` Bjorn Helgaas
2026-05-13 7:01 ` Leon Romanovsky
2026-05-06 9:46 ` Chengwen Feng [this message]
2026-05-06 12:39 ` [PATCH v6 2/6] PCI/TPH: Export pcie_tph_get_st_modes() for external use sashiko-bot
2026-05-06 9:46 ` [PATCH v6 3/6] vfio/pci: Add PCIe TPH interface with capability query Chengwen Feng
2026-05-06 18:48 ` sashiko-bot
2026-05-06 9:46 ` [PATCH v6 4/6] vfio/pci: Add PCIe TPH enable/disable support Chengwen Feng
2026-05-06 19:21 ` sashiko-bot
2026-05-06 9:46 ` [PATCH v6 5/6] vfio/pci: Add PCIe TPH GET_ST interface Chengwen Feng
2026-05-06 19:57 ` sashiko-bot
2026-05-06 9:46 ` [PATCH v6 6/6] vfio/pci: Add PCIe TPH SET_ST interface Chengwen Feng
2026-05-06 20:22 ` sashiko-bot
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