Merge branch 'topic/alex-vfio-prep' into next

* topic/alex-vfio-prep:
  PCI: misc pci_reg additions
  PCI: create common pcibios_err_to_errno
  PCI: export pci_user functions for use by other drivers
  PCI: add ACS validation utility
  PCI: add PCI DMA source ID quirk

drivers/pci/access.c

@@ -162,7 +162,8 @@ int pci_user_read_config_##size						\
 	if (ret > 0)							\
 		ret = -EINVAL;						\
 	return ret;							\
-}
+}									\
+EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
 
 /* Returns 0 on success, negative values indicate error. */
 #define PCI_USER_WRITE_CONFIG(size,type)				\
@@ -181,7 +182,8 @@ int pci_user_write_config_##size					\
 	if (ret > 0)							\
 		ret = -EINVAL;						\
 	return ret;							\
-}
+}									\
+EXPORT_SYMBOL_GPL(pci_user_write_config_##size);
 
 PCI_USER_READ_CONFIG(byte, u8)
 PCI_USER_READ_CONFIG(word, u16)

drivers/pci/pci.c

@@ -2292,6 +2292,75 @@ void pci_enable_acs(struct pci_dev *dev)
 	pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl);
 }
 
+/**
+ * pci_acs_enabled - test ACS against required flags for a given device
+ * @pdev: device to test
+ * @acs_flags: required PCI ACS flags
+ *
+ * Return true if the device supports the provided flags.  Automatically
+ * filters out flags that are not implemented on multifunction devices.
+ */
+bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags)
+{
+	int pos, ret;
+	u16 ctrl;
+
+	ret = pci_dev_specific_acs_enabled(pdev, acs_flags);
+	if (ret >= 0)
+		return ret > 0;
+
+	if (!pci_is_pcie(pdev))
+		return false;
+
+	/* Filter out flags not applicable to multifunction */
+	if (pdev->multifunction)
+		acs_flags &= (PCI_ACS_RR | PCI_ACS_CR |
+			      PCI_ACS_EC | PCI_ACS_DT);
+
+	if (pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM ||
+	    pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
+	    pdev->multifunction) {
+		pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS);
+		if (!pos)
+			return false;
+
+		pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl);
+		if ((ctrl & acs_flags) != acs_flags)
+			return false;
+	}
+
+	return true;
+}
+
+/**
+ * pci_acs_path_enable - test ACS flags from start to end in a hierarchy
+ * @start: starting downstream device
+ * @end: ending upstream device or NULL to search to the root bus
+ * @acs_flags: required flags
+ *
+ * Walk up a device tree from start to end testing PCI ACS support.  If
+ * any step along the way does not support the required flags, return false.
+ */
+bool pci_acs_path_enabled(struct pci_dev *start,
+			  struct pci_dev *end, u16 acs_flags)
+{
+	struct pci_dev *pdev, *parent = start;
+
+	do {
+		pdev = parent;
+
+		if (!pci_acs_enabled(pdev, acs_flags))
+			return false;
+
+		if (pci_is_root_bus(pdev->bus))
+			return (end == NULL);
+
+		parent = pdev->bus->self;
+	} while (pdev != end);
+
+	return true;
+}
+
 /**
  * pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge
  * @dev: the PCI device

drivers/pci/pci.h

@@ -86,13 +86,6 @@ static inline bool pci_is_bridge(struct pci_dev *pci_dev)
 	return !!(pci_dev->subordinate);
 }
 
-extern int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
-extern int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);
-extern int pci_user_read_config_dword(struct pci_dev *dev, int where, u32 *val);
-extern int pci_user_write_config_byte(struct pci_dev *dev, int where, u8 val);
-extern int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val);
-extern int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val);
-
 struct pci_vpd_ops {
 	ssize_t (*read)(struct pci_dev *dev, loff_t pos, size_t count, void *buf);
 	ssize_t (*write)(struct pci_dev *dev, loff_t pos, size_t count, const void *buf);

drivers/pci/quirks.c

@@ -3179,3 +3179,87 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 
 	return -ENOTTY;
 }
+
+static struct pci_dev *pci_func_0_dma_source(struct pci_dev *dev)
+{
+	if (!PCI_FUNC(dev->devfn))
+		return pci_dev_get(dev);
+
+	return pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
+}
+
+static const struct pci_dev_dma_source {
+	u16 vendor;
+	u16 device;
+	struct pci_dev *(*dma_source)(struct pci_dev *dev);
+} pci_dev_dma_source[] = {
+	/*
+	 * https://bugzilla.redhat.com/show_bug.cgi?id=605888
+	 *
+	 * Some Ricoh devices use the function 0 source ID for DMA on
+	 * other functions of a multifunction device.  The DMA devices
+	 * is therefore function 0, which will have implications of the
+	 * iommu grouping of these devices.
+	 */
+	{ PCI_VENDOR_ID_RICOH, 0xe822, pci_func_0_dma_source },
+	{ PCI_VENDOR_ID_RICOH, 0xe230, pci_func_0_dma_source },
+	{ PCI_VENDOR_ID_RICOH, 0xe832, pci_func_0_dma_source },
+	{ PCI_VENDOR_ID_RICOH, 0xe476, pci_func_0_dma_source },
+	{ 0 }
+};
+
+/*
+ * IOMMUs with isolation capabilities need to be programmed with the
+ * correct source ID of a device.  In most cases, the source ID matches
+ * the device doing the DMA, but sometimes hardware is broken and will
+ * tag the DMA as being sourced from a different device.  This function
+ * allows that translation.  Note that the reference count of the
+ * returned device is incremented on all paths.
+ */
+struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
+{
+	const struct pci_dev_dma_source *i;
+
+	for (i = pci_dev_dma_source; i->dma_source; i++) {
+		if ((i->vendor == dev->vendor ||
+		     i->vendor == (u16)PCI_ANY_ID) &&
+		    (i->device == dev->device ||
+		     i->device == (u16)PCI_ANY_ID))
+			return i->dma_source(dev);
+	}
+
+	return pci_dev_get(dev);
+}
+
+static const struct pci_dev_acs_enabled {
+	u16 vendor;
+	u16 device;
+	int (*acs_enabled)(struct pci_dev *dev, u16 acs_flags);
+} pci_dev_acs_enabled[] = {
+	{ 0 }
+};
+
+int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags)
+{
+	const struct pci_dev_acs_enabled *i;
+	int ret;
+
+	/*
+	 * Allow devices that do not expose standard PCIe ACS capabilities
+	 * or control to indicate their support here.  Multi-function express
+	 * devices which do not allow internal peer-to-peer between functions,
+	 * but do not implement PCIe ACS may wish to return true here.
+	 */
+	for (i = pci_dev_acs_enabled; i->acs_enabled; i++) {
+		if ((i->vendor == dev->vendor ||
+		     i->vendor == (u16)PCI_ANY_ID) &&
+		    (i->device == dev->device ||
+		     i->device == (u16)PCI_ANY_ID)) {
+			ret = i->acs_enabled(dev, acs_flags);
+			if (ret >= 0)
+				return ret;
+		}
+	}
+
+	return -ENOTTY;
+}

drivers/xen/xen-pciback/conf_space.c

@@ -124,7 +124,7 @@ static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
 	return val;
 }
 
-static int pcibios_err_to_errno(int err)
+static int xen_pcibios_err_to_errno(int err)
 {
 	switch (err) {
 	case PCIBIOS_SUCCESSFUL:
@@ -202,7 +202,7 @@ int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
 		       pci_name(dev), size, offset, value);
 
 	*ret_val = value;
-	return pcibios_err_to_errno(err);
+	return xen_pcibios_err_to_errno(err);
 }
 
 int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
@@ -290,7 +290,7 @@ int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
 		}
 	}
 
-	return pcibios_err_to_errno(err);
+	return xen_pcibios_err_to_errno(err);
 }
 
 void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev)

include/linux/pci.h

@@ -475,6 +475,32 @@ static inline bool pci_dev_msi_enabled(struct pci_dev *pci_dev) { return false;
 #define PCIBIOS_SET_FAILED		0x88
 #define PCIBIOS_BUFFER_TOO_SMALL	0x89
 
+/*
+ * Translate above to generic errno for passing back through non-pci.
+ */
+static inline int pcibios_err_to_errno(int err)
+{
+	if (err <= PCIBIOS_SUCCESSFUL)
+		return err; /* Assume already errno */
+
+	switch (err) {
+	case PCIBIOS_FUNC_NOT_SUPPORTED:
+		return -ENOENT;
+	case PCIBIOS_BAD_VENDOR_ID:
+		return -EINVAL;
+	case PCIBIOS_DEVICE_NOT_FOUND:
+		return -ENODEV;
+	case PCIBIOS_BAD_REGISTER_NUMBER:
+		return -EFAULT;
+	case PCIBIOS_SET_FAILED:
+		return -EIO;
+	case PCIBIOS_BUFFER_TOO_SMALL:
+		return -ENOSPC;
+	}
+
+	return -ENOTTY;
+}
+
 /* Low-level architecture-dependent routines */
 
 struct pci_ops {
@@ -779,6 +805,14 @@ static inline int pci_write_config_dword(const struct pci_dev *dev, int where,
 	return pci_bus_write_config_dword(dev->bus, dev->devfn, where, val);
 }
 
+/* user-space driven config access */
+int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
+int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);
+int pci_user_read_config_dword(struct pci_dev *dev, int where, u32 *val);
+int pci_user_write_config_byte(struct pci_dev *dev, int where, u8 val);
+int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val);
+int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val);
+
 int __must_check pci_enable_device(struct pci_dev *dev);
 int __must_check pci_enable_device_io(struct pci_dev *dev);
 int __must_check pci_enable_device_mem(struct pci_dev *dev);
@@ -1334,6 +1368,9 @@ static inline struct pci_dev *pci_get_bus_and_slot(unsigned int bus,
 static inline int pci_domain_nr(struct pci_bus *bus)
 { return 0; }
 
+static inline struct pci_dev *pci_dev_get(struct pci_dev *dev)
+{ return NULL; }
+
 #define dev_is_pci(d) (false)
 #define dev_is_pf(d) (false)
 #define dev_num_vf(d) (0)
@@ -1488,9 +1525,20 @@ enum pci_fixup_pass {
 
 #ifdef CONFIG_PCI_QUIRKS
 void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev);
+struct pci_dev *pci_get_dma_source(struct pci_dev *dev);
+int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags);
 #else
 static inline void pci_fixup_device(enum pci_fixup_pass pass,
 				    struct pci_dev *dev) {}
+static inline struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
+{
+	return pci_dev_get(dev);
+}
+static inline int pci_dev_specific_acs_enabled(struct pci_dev *dev,
+					       u16 acs_flags)
+{
+	return -ENOTTY;
+}
 #endif
 
 void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen);
@@ -1593,7 +1641,9 @@ static inline bool pci_is_pcie(struct pci_dev *dev)
 }
 
 void pci_request_acs(void);
-
+bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
+bool pci_acs_path_enabled(struct pci_dev *start,
+			  struct pci_dev *end, u16 acs_flags);
 
 #define PCI_VPD_LRDT			0x80	/* Large Resource Data Type */
 #define PCI_VPD_LRDT_ID(x)		(x | PCI_VPD_LRDT)