[PATCH v2 38/40] PCI: Make "PRG Response PASID Required" handling common

Jean-Philippe Brucker
2018-05-11T19:06:39Z

The PASID ECN to the PCIe spec added a bit in the PRI status register that
allows a Function to declare whether a PRG Response should contain the
PASID prefix or not.

Move the helper that accesses it from amd_iommu into the PCI subsystem,
renaming it to be consistent with the current PCI Express specification
(PRPR - PRG Response PASID Required).

Cc: bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org
Acked-by: Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org>
---
drivers/iommu/amd_iommu.c | 19 +------------------
drivers/pci/ats.c | 17 +++++++++++++++++
include/linux/pci-ats.h | 8 ++++++++
include/uapi/linux/pci_regs.h | 1 +
4 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 8fb8c737fffe..ac0d97fa514f 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2043,23 +2043,6 @@ static int pdev_iommuv2_enable(struct pci_dev *pdev)
return ret;
}

-/* FIXME: Move this to PCI code */
-#define PCI_PRI_TLP_OFF (1 << 15)
-
-static bool pci_pri_tlp_required(struct pci_dev *pdev)
-{
- u16 status;
- int pos;
-
- pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
- if (!pos)
- return false;
-
- pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
-
- return (status & PCI_PRI_TLP_OFF) ? true : false;
-}
-
/*
* If a device is not yet associated with a domain, this function
* assigns it visible for the hardware
@@ -2088,7 +2071,7 @@ static int attach_device(struct device *dev,

dev_data->ats.enabled = true;
dev_data->ats.qdep = pci_ats_queue_depth(pdev);
- dev_data->pri_tlp = pci_pri_tlp_required(pdev);
+ dev_data->pri_tlp = pci_prg_resp_requires_prefix(pdev);
}
} else if (amd_iommu_iotlb_sup &&
pci_enable_ats(pdev, PAGE_SHIFT) == 0) {
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 89305b569d3d..dc743e2fae7d 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -388,3 +388,20 @@ int pci_max_pasids(struct pci_dev *pdev)
}
EXPORT_SYMBOL_GPL(pci_max_pasids);
#endif /* CONFIG_PCI_PASID */
+
+#if defined(CONFIG_PCI_PASID) && defined(CONFIG_PCI_PRI)
+bool pci_prg_resp_requires_prefix(struct pci_dev *pdev)
+{
+ u16 status;
+ int pos;
+
+ pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
+ if (!pos)
+ return false;
+
+ pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
+
+ return !!(status & PCI_PRI_STATUS_PRPR);
+}
+EXPORT_SYMBOL_GPL(pci_prg_resp_requires_prefix);
+#endif /* CONFIG_PCI_PASID && CONFIG_PCI_PRI */
diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
index 7c4b8e27268c..1825ca2c9bf4 100644
--- a/include/linux/pci-ats.h
+++ b/include/linux/pci-ats.h
@@ -68,5 +68,13 @@ static inline int pci_max_pasids(struct pci_dev *pdev)

#endif /* CONFIG_PCI_PASID */

+#if defined(CONFIG_PCI_PASID) && defined(CONFIG_PCI_PRI)
+bool pci_prg_resp_requires_prefix(struct pci_dev *pdev);
+#else
+static inline bool pci_prg_resp_requires_prefix(struct pci_dev *pdev)
+{
+ return false;
+}
+#endif /* CONFIG_PCI_PASID && CONFIG_PCI_PRI */

#endif /* LINUX_PCI_ATS_H*/
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 103ba797a8f3..f9a11a13131c 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -871,6 +871,7 @@
#define PCI_PRI_STATUS_RF 0x001 /* Response Failure */
#define PCI_PRI_STATUS_UPRGI 0x002 /* Unexpected PRG index */
#define PCI_PRI_STATUS_STOPPED 0x100 /* PRI Stopped */
+#define PCI_PRI_STATUS_PRPR 0x8000 /* PRG Response requires PASID prefix */
#define PCI_PRI_MAX_REQ 0x08 /* PRI max reqs supported */
#define PCI_PRI_ALLOC_REQ 0x0c /* PRI max reqs allowed */
#define PCI_EXT_CAP_PRI_SIZEOF 16
--
2.17.0