Merge branch 'stable/xen-pciback-0.6.3' into stable/drivers

* stable/xen-pciback-0.6.3:
  xen/pciback: Have 'passthrough' option instead of XEN_PCIDEV_BACKEND_PASS and XEN_PCIDEV_BACKEND_VPCI
  xen/pciback: Remove the DEBUG option.
  xen/pciback: Drop two backends, squash and cleanup some code.
  xen/pciback: Print out the MSI/MSI-X (PIRQ) values
  xen/pciback: Don't setup an fake IRQ handler for SR-IOV devices.
  xen: rename pciback module to xen-pciback.
  xen/pciback: Fine-grain the spinlocks and fix BUG: scheduling while atomic cases.
  xen/pciback: Allocate IRQ handler for device that is shared with guest.
  xen/pciback: Disable MSI/MSI-X when reseting a device
  xen/pciback: guest SR-IOV support for PV guest
  xen/pciback: Register the owner (domain) of the PCI device.
  xen/pciback: Cleanup the driver based on checkpatch warnings and errors.
  xen/pciback: xen pci backend driver.

Conflicts:
	drivers/xen/Kconfig

drivers/xen/Kconfig

@@ -129,4 +129,26 @@ config XEN_TMEM
 	  Shim to interface in-kernel Transcendent Memory hooks
 	  (e.g. cleancache and frontswap) to Xen tmem hypercalls.
 
+config XEN_PCIDEV_BACKEND
+	tristate "Xen PCI-device backend driver"
+	depends on PCI && X86 && XEN
+	depends on XEN_BACKEND
+	default m
+	help
+	  The PCI device backend driver allows the kernel to export arbitrary
+	  PCI devices to other guests. If you select this to be a module, you
+	  will need to make sure no other driver has bound to the device(s)
+	  you want to make visible to other guests.
+
+	  The parameter "passthrough" allows you specify how you want the PCI
+	  devices to appear in the guest. You can choose the default (0) where
+	  PCI topology starts at 00.00.0, or (1) for passthrough if you want
+	  the PCI devices topology appear the same as in the host.
+
+	  The "hide" parameter (only applicable if backend driver is compiled
+	  into the kernel) allows you to bind the PCI devices to this module
+	  from the default device drivers. The argument is the list of PCI BDFs:
+	  xen-pciback.hide=(03:00.0)(04:00.0)
+
+	  If in doubt, say m.
 endmenu

drivers/xen/Makefile

@@ -18,6 +18,7 @@ obj-$(CONFIG_XEN_PLATFORM_PCI)		+= xen-platform-pci.o
 obj-$(CONFIG_XEN_TMEM)			+= tmem.o
 obj-$(CONFIG_SWIOTLB_XEN)		+= swiotlb-xen.o
 obj-$(CONFIG_XEN_DOM0)			+= pci.o
+obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
 
 xen-evtchn-y				:= evtchn.o
 xen-gntdev-y				:= gntdev.o

drivers/xen/xen-pciback/Makefile

+obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback.o
+
+xen-pciback-y := pci_stub.o pciback_ops.o xenbus.o
+xen-pciback-y += conf_space.o conf_space_header.o \
+		 conf_space_capability.o \
+		 conf_space_quirks.o vpci.o \
+		 passthrough.o

drivers/xen/xen-pciback/conf_space.h

+/*
+ * PCI Backend - Common data structures for overriding the configuration space
+ *
+ * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+
+#ifndef __XEN_PCIBACK_CONF_SPACE_H__
+#define __XEN_PCIBACK_CONF_SPACE_H__
+
+#include <linux/list.h>
+#include <linux/err.h>
+
+/* conf_field_init can return an errno in a ptr with ERR_PTR() */
+typedef void *(*conf_field_init) (struct pci_dev *dev, int offset);
+typedef void (*conf_field_reset) (struct pci_dev *dev, int offset, void *data);
+typedef void (*conf_field_free) (struct pci_dev *dev, int offset, void *data);
+
+typedef int (*conf_dword_write) (struct pci_dev *dev, int offset, u32 value,
+				 void *data);
+typedef int (*conf_word_write) (struct pci_dev *dev, int offset, u16 value,
+				void *data);
+typedef int (*conf_byte_write) (struct pci_dev *dev, int offset, u8 value,
+				void *data);
+typedef int (*conf_dword_read) (struct pci_dev *dev, int offset, u32 *value,
+				void *data);
+typedef int (*conf_word_read) (struct pci_dev *dev, int offset, u16 *value,
+			       void *data);
+typedef int (*conf_byte_read) (struct pci_dev *dev, int offset, u8 *value,
+			       void *data);
+
+/* These are the fields within the configuration space which we
+ * are interested in intercepting reads/writes to and changing their
+ * values.
+ */
+struct config_field {
+	unsigned int offset;
+	unsigned int size;
+	unsigned int mask;
+	conf_field_init init;
+	conf_field_reset reset;
+	conf_field_free release;
+	void (*clean) (struct config_field *field);
+	union {
+		struct {
+			conf_dword_write write;
+			conf_dword_read read;
+		} dw;
+		struct {
+			conf_word_write write;
+			conf_word_read read;
+		} w;
+		struct {
+			conf_byte_write write;
+			conf_byte_read read;
+		} b;
+	} u;
+	struct list_head list;
+};
+
+struct config_field_entry {
+	struct list_head list;
+	const struct config_field *field;
+	unsigned int base_offset;
+	void *data;
+};
+
+#define OFFSET(cfg_entry) ((cfg_entry)->base_offset+(cfg_entry)->field->offset)
+
+/* Add fields to a device - the add_fields macro expects to get a pointer to
+ * the first entry in an array (of which the ending is marked by size==0)
+ */
+int xen_pcibk_config_add_field_offset(struct pci_dev *dev,
+				    const struct config_field *field,
+				    unsigned int offset);
+
+static inline int xen_pcibk_config_add_field(struct pci_dev *dev,
+					   const struct config_field *field)
+{
+	return xen_pcibk_config_add_field_offset(dev, field, 0);
+}
+
+static inline int xen_pcibk_config_add_fields(struct pci_dev *dev,
+					    const struct config_field *field)
+{
+	int i, err = 0;
+	for (i = 0; field[i].size != 0; i++) {
+		err = xen_pcibk_config_add_field(dev, &field[i]);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+static inline int xen_pcibk_config_add_fields_offset(struct pci_dev *dev,
+					const struct config_field *field,
+					unsigned int offset)
+{
+	int i, err = 0;
+	for (i = 0; field[i].size != 0; i++) {
+		err = xen_pcibk_config_add_field_offset(dev, &field[i], offset);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/* Read/Write the real configuration space */
+int xen_pcibk_read_config_byte(struct pci_dev *dev, int offset, u8 *value,
+			       void *data);
+int xen_pcibk_read_config_word(struct pci_dev *dev, int offset, u16 *value,
+			       void *data);
+int xen_pcibk_read_config_dword(struct pci_dev *dev, int offset, u32 *value,
+				void *data);
+int xen_pcibk_write_config_byte(struct pci_dev *dev, int offset, u8 value,
+				 void *data);
+int xen_pcibk_write_config_word(struct pci_dev *dev, int offset, u16 value,
+				void *data);
+int xen_pcibk_write_config_dword(struct pci_dev *dev, int offset, u32 value,
+				 void *data);
+
+int xen_pcibk_config_capability_init(void);
+
+int xen_pcibk_config_header_add_fields(struct pci_dev *dev);
+int xen_pcibk_config_capability_add_fields(struct pci_dev *dev);
+
+#endif				/* __XEN_PCIBACK_CONF_SPACE_H__ */

drivers/xen/xen-pciback/conf_space_capability.c

+/*
+ * PCI Backend - Handles the virtual fields found on the capability lists
+ *               in the configuration space.
+ *
+ * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include "pciback.h"
+#include "conf_space.h"
+
+static LIST_HEAD(capabilities);
+struct xen_pcibk_config_capability {
+	struct list_head cap_list;
+
+	int capability;
+
+	/* If the device has the capability found above, add these fields */
+	const struct config_field *fields;
+};
+
+static const struct config_field caplist_header[] = {
+	{
+	 .offset    = PCI_CAP_LIST_ID,
+	 .size      = 2, /* encompass PCI_CAP_LIST_ID & PCI_CAP_LIST_NEXT */
+	 .u.w.read  = xen_pcibk_read_config_word,
+	 .u.w.write = NULL,
+	},
+	{}
+};
+
+static inline void register_capability(struct xen_pcibk_config_capability *cap)
+{
+	list_add_tail(&cap->cap_list, &capabilities);
+}
+
+int xen_pcibk_config_capability_add_fields(struct pci_dev *dev)
+{
+	int err = 0;
+	struct xen_pcibk_config_capability *cap;
+	int cap_offset;
+
+	list_for_each_entry(cap, &capabilities, cap_list) {
+		cap_offset = pci_find_capability(dev, cap->capability);
+		if (cap_offset) {
+			dev_dbg(&dev->dev, "Found capability 0x%x at 0x%x\n",
+				cap->capability, cap_offset);
+
+			err = xen_pcibk_config_add_fields_offset(dev,
+							       caplist_header,
+							       cap_offset);
+			if (err)
+				goto out;
+			err = xen_pcibk_config_add_fields_offset(dev,
+							       cap->fields,
+							       cap_offset);
+			if (err)
+				goto out;
+		}
+	}
+
+out:
+	return err;
+}
+
+static int vpd_address_write(struct pci_dev *dev, int offset, u16 value,
+			     void *data)
+{
+	/* Disallow writes to the vital product data */
+	if (value & PCI_VPD_ADDR_F)
+		return PCIBIOS_SET_FAILED;
+	else
+		return pci_write_config_word(dev, offset, value);
+}
+
+static const struct config_field caplist_vpd[] = {
+	{
+	 .offset    = PCI_VPD_ADDR,
+	 .size      = 2,
+	 .u.w.read  = xen_pcibk_read_config_word,
+	 .u.w.write = vpd_address_write,
+	 },
+	{
+	 .offset     = PCI_VPD_DATA,
+	 .size       = 4,
+	 .u.dw.read  = xen_pcibk_read_config_dword,
+	 .u.dw.write = NULL,
+	 },
+	{}
+};
+
+static int pm_caps_read(struct pci_dev *dev, int offset, u16 *value,
+			void *data)
+{
+	int err;
+	u16 real_value;
+
+	err = pci_read_config_word(dev, offset, &real_value);
+	if (err)
+		goto out;
+
+	*value = real_value & ~PCI_PM_CAP_PME_MASK;
+
+out:
+	return err;
+}
+
+/* PM_OK_BITS specifies the bits that the driver domain is allowed to change.
+ * Can't allow driver domain to enable PMEs - they're shared */
+#define PM_OK_BITS (PCI_PM_CTRL_PME_STATUS|PCI_PM_CTRL_DATA_SEL_MASK)
+
+static int pm_ctrl_write(struct pci_dev *dev, int offset, u16 new_value,
+			 void *data)
+{
+	int err;
+	u16 old_value;
+	pci_power_t new_state, old_state;
+
+	err = pci_read_config_word(dev, offset, &old_value);
+	if (err)
+		goto out;
+
+	old_state = (pci_power_t)(old_value & PCI_PM_CTRL_STATE_MASK);
+	new_state = (pci_power_t)(new_value & PCI_PM_CTRL_STATE_MASK);
+
+	new_value &= PM_OK_BITS;
+	if ((old_value & PM_OK_BITS) != new_value) {
+		new_value = (old_value & ~PM_OK_BITS) | new_value;
+		err = pci_write_config_word(dev, offset, new_value);
+		if (err)
+			goto out;
+	}
+
+	/* Let pci core handle the power management change */
+	dev_dbg(&dev->dev, "set power state to %x\n", new_state);
+	err = pci_set_power_state(dev, new_state);
+	if (err) {
+		err = PCIBIOS_SET_FAILED;
+		goto out;
+	}
+
+ out:
+	return err;
+}
+
+/* Ensure PMEs are disabled */
+static void *pm_ctrl_init(struct pci_dev *dev, int offset)
+{
+	int err;
+	u16 value;
+
+	err = pci_read_config_word(dev, offset, &value);
+	if (err)
+		goto out;
+
+	if (value & PCI_PM_CTRL_PME_ENABLE) {
+		value &= ~PCI_PM_CTRL_PME_ENABLE;
+		err = pci_write_config_word(dev, offset, value);
+	}
+
+out:
+	return ERR_PTR(err);
+}
+
+static const struct config_field caplist_pm[] = {
+	{
+		.offset     = PCI_PM_PMC,
+		.size       = 2,
+		.u.w.read   = pm_caps_read,
+	},
+	{
+		.offset     = PCI_PM_CTRL,
+		.size       = 2,
+		.init       = pm_ctrl_init,
+		.u.w.read   = xen_pcibk_read_config_word,
+		.u.w.write  = pm_ctrl_write,
+	},
+	{
+		.offset     = PCI_PM_PPB_EXTENSIONS,
+		.size       = 1,
+		.u.b.read   = xen_pcibk_read_config_byte,
+	},
+	{
+		.offset     = PCI_PM_DATA_REGISTER,
+		.size       = 1,
+		.u.b.read   = xen_pcibk_read_config_byte,
+	},
+	{}
+};
+
+static struct xen_pcibk_config_capability xen_pcibk_config_capability_pm = {
+	.capability = PCI_CAP_ID_PM,
+	.fields = caplist_pm,
+};
+static struct xen_pcibk_config_capability xen_pcibk_config_capability_vpd = {
+	.capability = PCI_CAP_ID_VPD,
+	.fields = caplist_vpd,
+};
+
+int xen_pcibk_config_capability_init(void)
+{
+	register_capability(&xen_pcibk_config_capability_vpd);
+	register_capability(&xen_pcibk_config_capability_pm);
+
+	return 0;
+}

drivers/xen/xen-pciback/conf_space_header.c

+/*
+ * PCI Backend - Handles the virtual fields in the configuration space headers.
+ *
+ * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include "pciback.h"
+#include "conf_space.h"
+
+struct pci_bar_info {
+	u32 val;
+	u32 len_val;
+	int which;
+};
+
+#define DRV_NAME	"xen-pciback"
+#define is_enable_cmd(value) ((value)&(PCI_COMMAND_MEMORY|PCI_COMMAND_IO))
+#define is_master_cmd(value) ((value)&PCI_COMMAND_MASTER)
+
+static int command_read(struct pci_dev *dev, int offset, u16 *value, void *data)
+{
+	int i;
+	int ret;
+
+	ret = xen_pcibk_read_config_word(dev, offset, value, data);
+	if (!atomic_read(&dev->enable_cnt))
+		return ret;
+
+	for (i = 0; i < PCI_ROM_RESOURCE; i++) {
+		if (dev->resource[i].flags & IORESOURCE_IO)
+			*value |= PCI_COMMAND_IO;
+		if (dev->resource[i].flags & IORESOURCE_MEM)
+			*value |= PCI_COMMAND_MEMORY;
+	}
+
+	return ret;
+}
+
+static int command_write(struct pci_dev *dev, int offset, u16 value, void *data)
+{
+	struct xen_pcibk_dev_data *dev_data;
+	int err;
+
+	dev_data = pci_get_drvdata(dev);
+	if (!pci_is_enabled(dev) && is_enable_cmd(value)) {
+		if (unlikely(verbose_request))
+			printk(KERN_DEBUG DRV_NAME ": %s: enable\n",
+			       pci_name(dev));
+		err = pci_enable_device(dev);
+		if (err)
+			return err;
+		if (dev_data)
+			dev_data->enable_intx = 1;
+	} else if (pci_is_enabled(dev) && !is_enable_cmd(value)) {
+		if (unlikely(verbose_request))
+			printk(KERN_DEBUG DRV_NAME ": %s: disable\n",
+			       pci_name(dev));
+		pci_disable_device(dev);
+		if (dev_data)
+			dev_data->enable_intx = 0;
+	}
+
+	if (!dev->is_busmaster && is_master_cmd(value)) {
+		if (unlikely(verbose_request))
+			printk(KERN_DEBUG DRV_NAME ": %s: set bus master\n",
+			       pci_name(dev));
+		pci_set_master(dev);
+	}
+
+	if (value & PCI_COMMAND_INVALIDATE) {
+		if (unlikely(verbose_request))
+			printk(KERN_DEBUG
+			       DRV_NAME ": %s: enable memory-write-invalidate\n",
+			       pci_name(dev));
+		err = pci_set_mwi(dev);
+		if (err) {
+			printk(KERN_WARNING
+			       DRV_NAME ": %s: cannot enable "
+			       "memory-write-invalidate (%d)\n",
+			       pci_name(dev), err);
+			value &= ~PCI_COMMAND_INVALIDATE;
+		}
+	}
+
+	return pci_write_config_word(dev, offset, value);
+}
+
+static int rom_write(struct pci_dev *dev, int offset, u32 value, void *data)
+{
+	struct pci_bar_info *bar = data;
+
+	if (unlikely(!bar)) {
+		printk(KERN_WARNING DRV_NAME ": driver data not found for %s\n",
+		       pci_name(dev));
+		return XEN_PCI_ERR_op_failed;
+	}
+
+	/* A write to obtain the length must happen as a 32-bit write.
+	 * This does not (yet) support writing individual bytes
+	 */
+	if (value == ~PCI_ROM_ADDRESS_ENABLE)
+		bar->which = 1;
+	else {
+		u32 tmpval;
+		pci_read_config_dword(dev, offset, &tmpval);
+		if (tmpval != bar->val && value == bar->val) {
+			/* Allow restoration of bar value. */
+			pci_write_config_dword(dev, offset, bar->val);
+		}
+		bar->which = 0;
+	}
+
+	/* Do we need to support enabling/disabling the rom address here? */
+
+	return 0;
+}
+
+/* For the BARs, only allow writes which write ~0 or
+ * the correct resource information
+ * (Needed for when the driver probes the resource usage)
+ */
+static int bar_write(struct pci_dev *dev, int offset, u32 value, void *data)
+{
+	struct pci_bar_info *bar = data;
+
+	if (unlikely(!bar)) {
+		printk(KERN_WARNING DRV_NAME ": driver data not found for %s\n",
+		       pci_name(dev));
+		return XEN_PCI_ERR_op_failed;
+	}
+
+	/* A write to obtain the length must happen as a 32-bit write.
+	 * This does not (yet) support writing individual bytes
+	 */
+	if (value == ~0)
+		bar->which = 1;
+	else {
+		u32 tmpval;
+		pci_read_config_dword(dev, offset, &tmpval);
+		if (tmpval != bar->val && value == bar->val) {
+			/* Allow restoration of bar value. */
+			pci_write_config_dword(dev, offset, bar->val);
+		}
+		bar->which = 0;
+	}
+
+	return 0;
+}
+
+static int bar_read(struct pci_dev *dev, int offset, u32 * value, void *data)
+{
+	struct pci_bar_info *bar = data;
+
+	if (unlikely(!bar)) {
+		printk(KERN_WARNING DRV_NAME ": driver data not found for %s\n",
+		       pci_name(dev));
+		return XEN_PCI_ERR_op_failed;
+	}
+
+	*value = bar->which ? bar->len_val : bar->val;
+
+	return 0;
+}
+
+static inline void read_dev_bar(struct pci_dev *dev,
+				struct pci_bar_info *bar_info, int offset,
+				u32 len_mask)
+{
+	int	pos;
+	struct resource	*res = dev->resource;
+
+	if (offset == PCI_ROM_ADDRESS || offset == PCI_ROM_ADDRESS1)
+		pos = PCI_ROM_RESOURCE;
+	else {
+		pos = (offset - PCI_BASE_ADDRESS_0) / 4;
+		if (pos && ((res[pos - 1].flags & (PCI_BASE_ADDRESS_SPACE |
+				PCI_BASE_ADDRESS_MEM_TYPE_MASK)) ==
+			   (PCI_BASE_ADDRESS_SPACE_MEMORY |
+				PCI_BASE_ADDRESS_MEM_TYPE_64))) {
+			bar_info->val = res[pos - 1].start >> 32;
+			bar_info->len_val = res[pos - 1].end >> 32;
+			return;
+		}
+	}
+
+	bar_info->val = res[pos].start |
+			(res[pos].flags & PCI_REGION_FLAG_MASK);
+	bar_info->len_val = res[pos].end - res[pos].start + 1;
+}
+
+static void *bar_init(struct pci_dev *dev, int offset)
+{
+	struct pci_bar_info *bar = kmalloc(sizeof(*bar), GFP_KERNEL);
+
+	if (!bar)
+		return ERR_PTR(-ENOMEM);
+
+	read_dev_bar(dev, bar, offset, ~0);
+	bar->which = 0;
+
+	return bar;
+}
+
+static void *rom_init(struct pci_dev *dev, int offset)
+{
+	struct pci_bar_info *bar = kmalloc(sizeof(*bar), GFP_KERNEL);
+
+	if (!bar)
+		return ERR_PTR(-ENOMEM);
+
+	read_dev_bar(dev, bar, offset, ~PCI_ROM_ADDRESS_ENABLE);
+	bar->which = 0;
+
+	return bar;
+}
+
+static void bar_reset(struct pci_dev *dev, int offset, void *data)
+{
+	struct pci_bar_info *bar = data;
+
+	bar->which = 0;
+}
+
+static void bar_release(struct pci_dev *dev, int offset, void *data)
+{
+	kfree(data);
+}
+
+static int xen_pcibk_read_vendor(struct pci_dev *dev, int offset,
+			       u16 *value, void *data)
+{
+	*value = dev->vendor;
+
+	return 0;
+}
+
+static int xen_pcibk_read_device(struct pci_dev *dev, int offset,
+			       u16 *value, void *data)
+{
+	*value = dev->device;
+
+	return 0;
+}
+
+static int interrupt_read(struct pci_dev *dev, int offset, u8 * value,
+			  void *data)
+{
+	*value = (u8) dev->irq;
+
+	return 0;
+}
+
+static int bist_write(struct pci_dev *dev, int offset, u8 value, void *data)
+{
+	u8 cur_value;
+	int err;
+
+	err = pci_read_config_byte(dev, offset, &cur_value);
+	if (err)
+		goto out;
+
+	if ((cur_value & ~PCI_BIST_START) == (value & ~PCI_BIST_START)
+	    || value == PCI_BIST_START)
+		err = pci_write_config_byte(dev, offset, value);
+
+out:
+	return err;
+}
+
+static const struct config_field header_common[] = {
+	{
+	 .offset    = PCI_VENDOR_ID,
+	 .size      = 2,
+	 .u.w.read  = xen_pcibk_read_vendor,
+	},
+	{
+	 .offset    = PCI_DEVICE_ID,
+	 .size      = 2,
+	 .u.w.read  = xen_pcibk_read_device,
+	},
+	{
+	 .offset    = PCI_COMMAND,
+	 .size      = 2,
+	 .u.w.read  = command_read,
+	 .u.w.write = command_write,
+	},
+	{
+	 .offset    = PCI_INTERRUPT_LINE,
+	 .size      = 1,
+	 .u.b.read  = interrupt_read,
+	},
+	{
+	 .offset    = PCI_INTERRUPT_PIN,
+	 .size      = 1,
+	 .u.b.read  = xen_pcibk_read_config_byte,
+	},
+	{
+	 /* Any side effects of letting driver domain control cache line? */
+	 .offset    = PCI_CACHE_LINE_SIZE,
+	 .size      = 1,
+	 .u.b.read  = xen_pcibk_read_config_byte,
+	 .u.b.write = xen_pcibk_write_config_byte,
+	},
+	{
+	 .offset    = PCI_LATENCY_TIMER,
+	 .size      = 1,
+	 .u.b.read  = xen_pcibk_read_config_byte,
+	},
+	{
+	 .offset    = PCI_BIST,
+	 .size      = 1,
+	 .u.b.read  = xen_pcibk_read_config_byte,
+	 .u.b.write = bist_write,
+	},
+	{}
+};
+
+#define CFG_FIELD_BAR(reg_offset)			\
+	{						\
+	.offset     = reg_offset,			\
+	.size       = 4,				\
+	.init       = bar_init,				\
+	.reset      = bar_reset,			\
+	.release    = bar_release,			\
+	.u.dw.read  = bar_read,				\
+	.u.dw.write = bar_write,			\
+	}
+
+#define CFG_FIELD_ROM(reg_offset)			\
+	{						\
+	.offset     = reg_offset,			\
+	.size       = 4,				\
+	.init       = rom_init,				\
+	.reset      = bar_reset,			\
+	.release    = bar_release,			\
+	.u.dw.read  = bar_read,				\
+	.u.dw.write = rom_write,			\
+	}
+
+static const struct config_field header_0[] = {
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_0),
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_1),
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_2),
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_3),
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_4),
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_5),
+	CFG_FIELD_ROM(PCI_ROM_ADDRESS),
+	{}
+};
+
+static const struct config_field header_1[] = {
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_0),
+	CFG_FIELD_BAR(PCI_BASE_ADDRESS_1),
+	CFG_FIELD_ROM(PCI_ROM_ADDRESS1),
+	{}
+};
+
+int xen_pcibk_config_header_add_fields(struct pci_dev *dev)
+{
+	int err;
+
+	err = xen_pcibk_config_add_fields(dev, header_common);
+	if (err)
+		goto out;
+
+	switch (dev->hdr_type) {
+	case PCI_HEADER_TYPE_NORMAL:
+		err = xen_pcibk_config_add_fields(dev, header_0);
+		break;
+
+	case PCI_HEADER_TYPE_BRIDGE:
+		err = xen_pcibk_config_add_fields(dev, header_1);
+		break;
+
+	default:
+		err = -EINVAL;
+		printk(KERN_ERR DRV_NAME ": %s: Unsupported header type %d!\n",
+		       pci_name(dev), dev->hdr_type);
+		break;
+	}
+
+out:
+	return err;
+}

drivers/xen/xen-pciback/conf_space_quirks.c

+/*
+ * PCI Backend - Handle special overlays for broken devices.
+ *
+ * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ * Author: Chris Bookholt <hap10@epoch.ncsc.mil>
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include "pciback.h"
+#include "conf_space.h"
+#include "conf_space_quirks.h"
+
+LIST_HEAD(xen_pcibk_quirks);
+#define	DRV_NAME	"xen-pciback"
+static inline const struct pci_device_id *
+match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
+{
+	if ((id->vendor == PCI_ANY_ID || id->vendor == dev->vendor) &&
+	    (id->device == PCI_ANY_ID || id->device == dev->device) &&
+	    (id->subvendor == PCI_ANY_ID ||
+				id->subvendor == dev->subsystem_vendor) &&
+	    (id->subdevice == PCI_ANY_ID ||
+				id->subdevice == dev->subsystem_device) &&
+	    !((id->class ^ dev->class) & id->class_mask))
+		return id;
+	return NULL;
+}
+
+static struct xen_pcibk_config_quirk *xen_pcibk_find_quirk(struct pci_dev *dev)
+{
+	struct xen_pcibk_config_quirk *tmp_quirk;
+
+	list_for_each_entry(tmp_quirk, &xen_pcibk_quirks, quirks_list)
+		if (match_one_device(&tmp_quirk->devid, dev) != NULL)
+			goto out;
+	tmp_quirk = NULL;
+	printk(KERN_DEBUG DRV_NAME
+	       ":quirk didn't match any device xen_pciback knows about\n");
+out:
+	return tmp_quirk;
+}
+
+static inline void register_quirk(struct xen_pcibk_config_quirk *quirk)
+{
+	list_add_tail(&quirk->quirks_list, &xen_pcibk_quirks);
+}
+
+int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg)
+{
+	int ret = 0;
+	struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev);
+	struct config_field_entry *cfg_entry;
+
+	list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
+		if (OFFSET(cfg_entry) == reg) {
+			ret = 1;
+			break;
+		}
+	}
+	return ret;
+}
+
+int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
+				    *field)
+{
+	int err = 0;
+
+	switch (field->size) {
+	case 1:
+		field->u.b.read = xen_pcibk_read_config_byte;
+		field->u.b.write = xen_pcibk_write_config_byte;
+		break;
+	case 2:
+		field->u.w.read = xen_pcibk_read_config_word;
+		field->u.w.write = xen_pcibk_write_config_word;
+		break;
+	case 4:
+		field->u.dw.read = xen_pcibk_read_config_dword;
+		field->u.dw.write = xen_pcibk_write_config_dword;
+		break;
+	default:
+		err = -EINVAL;
+		goto out;
+	}
+
+	xen_pcibk_config_add_field(dev, field);
+
+out:
+	return err;
+}
+
+int xen_pcibk_config_quirks_init(struct pci_dev *dev)
+{
+	struct xen_pcibk_config_quirk *quirk;
+	int ret = 0;
+
+	quirk = kzalloc(sizeof(*quirk), GFP_ATOMIC);
+	if (!quirk) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	quirk->devid.vendor = dev->vendor;
+	quirk->devid.device = dev->device;
+	quirk->devid.subvendor = dev->subsystem_vendor;
+	quirk->devid.subdevice = dev->subsystem_device;
+	quirk->devid.class = 0;
+	quirk->devid.class_mask = 0;
+	quirk->devid.driver_data = 0UL;
+
+	quirk->pdev = dev;
+
+	register_quirk(quirk);
+out:
+	return ret;
+}
+
+void xen_pcibk_config_field_free(struct config_field *field)
+{
+	kfree(field);
+}
+
+int xen_pcibk_config_quirk_release(struct pci_dev *dev)
+{
+	struct xen_pcibk_config_quirk *quirk;
+	int ret = 0;
+
+	quirk = xen_pcibk_find_quirk(dev);
+	if (!quirk) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	list_del(&quirk->quirks_list);
+	kfree(quirk);
+
+out:
+	return ret;
+}

drivers/xen/xen-pciback/conf_space_quirks.h

+/*
+ * PCI Backend - Data structures for special overlays for broken devices.
+ *
+ * Ryan Wilson <hap9@epoch.ncsc.mil>
+ * Chris Bookholt <hap10@epoch.ncsc.mil>
+ */
+
+#ifndef __XEN_PCIBACK_CONF_SPACE_QUIRKS_H__
+#define __XEN_PCIBACK_CONF_SPACE_QUIRKS_H__
+
+#include <linux/pci.h>
+#include <linux/list.h>
+
+struct xen_pcibk_config_quirk {
+	struct list_head quirks_list;
+	struct pci_device_id devid;
+	struct pci_dev *pdev;
+};
+
+int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field
+				    *field);
+
+int xen_pcibk_config_quirks_remove_field(struct pci_dev *dev, int reg);
+
+int xen_pcibk_config_quirks_init(struct pci_dev *dev);
+
+void xen_pcibk_config_field_free(struct config_field *field);
+
+int xen_pcibk_config_quirk_release(struct pci_dev *dev);
+
+int xen_pcibk_field_is_dup(struct pci_dev *dev, unsigned int reg);
+
+#endif

drivers/xen/xen-pciback/passthrough.c

+/*
+ * PCI Backend - Provides restricted access to the real PCI bus topology
+ *               to the frontend
+ *
+ *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+
+#include <linux/list.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include "pciback.h"
+
+struct passthrough_dev_data {
+	/* Access to dev_list must be protected by lock */
+	struct list_head dev_list;
+	spinlock_t lock;
+};
+
+static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
+					       unsigned int domain,
+					       unsigned int bus,
+					       unsigned int devfn)
+{
+	struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
+	struct pci_dev_entry *dev_entry;
+	struct pci_dev *dev = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev_data->lock, flags);
+
+	list_for_each_entry(dev_entry, &dev_data->dev_list, list) {
+		if (domain == (unsigned int)pci_domain_nr(dev_entry->dev->bus)
+		    && bus == (unsigned int)dev_entry->dev->bus->number
+		    && devfn == dev_entry->dev->devfn) {
+			dev = dev_entry->dev;
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&dev_data->lock, flags);
+
+	return dev;
+}
+
+static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
+				   struct pci_dev *dev,
+				   int devid, publish_pci_dev_cb publish_cb)
+{
+	struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
+	struct pci_dev_entry *dev_entry;
+	unsigned long flags;
+	unsigned int domain, bus, devfn;
+	int err;
+
+	dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
+	if (!dev_entry)
+		return -ENOMEM;
+	dev_entry->dev = dev;
+
+	spin_lock_irqsave(&dev_data->lock, flags);
+	list_add_tail(&dev_entry->list, &dev_data->dev_list);
+	spin_unlock_irqrestore(&dev_data->lock, flags);
+
+	/* Publish this device. */
+	domain = (unsigned int)pci_domain_nr(dev->bus);
+	bus = (unsigned int)dev->bus->number;
+	devfn = dev->devfn;
+	err = publish_cb(pdev, domain, bus, devfn, devid);
+
+	return err;
+}
+
+static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
+					struct pci_dev *dev)
+{
+	struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
+	struct pci_dev_entry *dev_entry, *t;
+	struct pci_dev *found_dev = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev_data->lock, flags);
+
+	list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {
+		if (dev_entry->dev == dev) {
+			list_del(&dev_entry->list);
+			found_dev = dev_entry->dev;
+			kfree(dev_entry);
+		}
+	}
+
+	spin_unlock_irqrestore(&dev_data->lock, flags);
+
+	if (found_dev)
+		pcistub_put_pci_dev(found_dev);
+}
+
+static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
+{
+	struct passthrough_dev_data *dev_data;
+
+	dev_data = kmalloc(sizeof(*dev_data), GFP_KERNEL);
+	if (!dev_data)
+		return -ENOMEM;
+
+	spin_lock_init(&dev_data->lock);
+
+	INIT_LIST_HEAD(&dev_data->dev_list);
+
+	pdev->pci_dev_data = dev_data;
+
+	return 0;
+}
+
+static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
+					 publish_pci_root_cb publish_root_cb)
+{
+	int err = 0;
+	struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
+	struct pci_dev_entry *dev_entry, *e, *tmp;
+	struct pci_dev *dev;
+	int found;
+	unsigned int domain, bus;
+
+	spin_lock(&dev_data->lock);
+
+	list_for_each_entry_safe(dev_entry, tmp, &dev_data->dev_list, list) {
+		/* Only publish this device as a root if none of its
+		 * parent bridges are exported
+		 */
+		found = 0;
+		dev = dev_entry->dev->bus->self;
+		for (; !found && dev != NULL; dev = dev->bus->self) {
+			list_for_each_entry(e, &dev_data->dev_list, list) {
+				if (dev == e->dev) {
+					found = 1;
+					break;
+				}
+			}
+		}
+
+		domain = (unsigned int)pci_domain_nr(dev_entry->dev->bus);
+		bus = (unsigned int)dev_entry->dev->bus->number;
+
+		if (!found) {
+			spin_unlock(&dev_data->lock);
+			err = publish_root_cb(pdev, domain, bus);
+			if (err)
+				break;
+			spin_lock(&dev_data->lock);
+		}
+	}
+
+	if (!err)
+		spin_unlock(&dev_data->lock);
+
+	return err;
+}
+
+static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
+{
+	struct passthrough_dev_data *dev_data = pdev->pci_dev_data;
+	struct pci_dev_entry *dev_entry, *t;
+
+	list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) {
+		list_del(&dev_entry->list);
+		pcistub_put_pci_dev(dev_entry->dev);
+		kfree(dev_entry);
+	}
+
+	kfree(dev_data);
+	pdev->pci_dev_data = NULL;
+}
+
+static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
+					struct xen_pcibk_device *pdev,
+					unsigned int *domain, unsigned int *bus,
+					unsigned int *devfn)
+{
+	*domain = pci_domain_nr(pcidev->bus);
+	*bus = pcidev->bus->number;
+	*devfn = pcidev->devfn;
+	return 1;
+}
+
+struct xen_pcibk_backend xen_pcibk_passthrough_backend = {
+	.name           = "passthrough",
+	.init           = __xen_pcibk_init_devices,
+	.free		= __xen_pcibk_release_devices,
+	.find           = __xen_pcibk_get_pcifront_dev,
+	.publish        = __xen_pcibk_publish_pci_roots,
+	.release        = __xen_pcibk_release_pci_dev,
+	.add            = __xen_pcibk_add_pci_dev,
+	.get            = __xen_pcibk_get_pci_dev,
+};

drivers/xen/xen-pciback/pciback.h

+/*
+ * PCI Backend Common Data Structures & Function Declarations
+ *
+ *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+#ifndef __XEN_PCIBACK_H__
+#define __XEN_PCIBACK_H__
+
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <xen/xenbus.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/atomic.h>
+#include <xen/interface/io/pciif.h>
+
+struct pci_dev_entry {
+	struct list_head list;
+	struct pci_dev *dev;
+};
+
+#define _PDEVF_op_active	(0)
+#define PDEVF_op_active		(1<<(_PDEVF_op_active))
+#define _PCIB_op_pending	(1)
+#define PCIB_op_pending		(1<<(_PCIB_op_pending))
+
+struct xen_pcibk_device {
+	void *pci_dev_data;
+	spinlock_t dev_lock;
+	struct xenbus_device *xdev;
+	struct xenbus_watch be_watch;
+	u8 be_watching;
+	int evtchn_irq;
+	struct xen_pci_sharedinfo *sh_info;
+	unsigned long flags;
+	struct work_struct op_work;
+};
+
+struct xen_pcibk_dev_data {
+	struct list_head config_fields;
+	unsigned int permissive:1;
+	unsigned int warned_on_write:1;
+	unsigned int enable_intx:1;
+	unsigned int isr_on:1; /* Whether the IRQ handler is installed. */
+	unsigned int ack_intr:1; /* .. and ACK-ing */
+	unsigned long handled;
+	unsigned int irq; /* Saved in case device transitions to MSI/MSI-X */
+	char irq_name[0]; /* xen-pcibk[000:04:00.0] */
+};
+
+/* Used by XenBus and xen_pcibk_ops.c */
+extern wait_queue_head_t xen_pcibk_aer_wait_queue;
+extern struct workqueue_struct *xen_pcibk_wq;
+/* Used by pcistub.c and conf_space_quirks.c */
+extern struct list_head xen_pcibk_quirks;
+
+/* Get/Put PCI Devices that are hidden from the PCI Backend Domain */
+struct pci_dev *pcistub_get_pci_dev_by_slot(struct xen_pcibk_device *pdev,
+					    int domain, int bus,
+					    int slot, int func);
+struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev,
+				    struct pci_dev *dev);
+void pcistub_put_pci_dev(struct pci_dev *dev);
+
+/* Ensure a device is turned off or reset */
+void xen_pcibk_reset_device(struct pci_dev *pdev);
+
+/* Access a virtual configuration space for a PCI device */
+int xen_pcibk_config_init(void);
+int xen_pcibk_config_init_dev(struct pci_dev *dev);
+void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev);
+void xen_pcibk_config_reset_dev(struct pci_dev *dev);
+void xen_pcibk_config_free_dev(struct pci_dev *dev);
+int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
+			  u32 *ret_val);
+int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size,
+			   u32 value);
+
+/* Handle requests for specific devices from the frontend */
+typedef int (*publish_pci_dev_cb) (struct xen_pcibk_device *pdev,
+				   unsigned int domain, unsigned int bus,
+				   unsigned int devfn, unsigned int devid);
+typedef int (*publish_pci_root_cb) (struct xen_pcibk_device *pdev,
+				    unsigned int domain, unsigned int bus);
+
+/* Backend registration for the two types of BDF representation:
+ *  vpci - BDFs start at 00
+ *  passthrough - BDFs are exactly like in the host.
+ */
+struct xen_pcibk_backend {
+	char *name;
+	int (*init)(struct xen_pcibk_device *pdev);
+	void (*free)(struct xen_pcibk_device *pdev);
+	int (*find)(struct pci_dev *pcidev, struct xen_pcibk_device *pdev,
+		    unsigned int *domain, unsigned int *bus,
+		    unsigned int *devfn);
+	int (*publish)(struct xen_pcibk_device *pdev, publish_pci_root_cb cb);
+	void (*release)(struct xen_pcibk_device *pdev, struct pci_dev *dev);
+	int (*add)(struct xen_pcibk_device *pdev, struct pci_dev *dev,
+		   int devid, publish_pci_dev_cb publish_cb);
+	struct pci_dev *(*get)(struct xen_pcibk_device *pdev,
+			       unsigned int domain, unsigned int bus,
+			       unsigned int devfn);
+};
+
+extern struct xen_pcibk_backend xen_pcibk_vpci_backend;
+extern struct xen_pcibk_backend xen_pcibk_passthrough_backend;
+extern struct xen_pcibk_backend *xen_pcibk_backend;
+
+static inline int xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
+					struct pci_dev *dev,
+					int devid,
+					publish_pci_dev_cb publish_cb)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->add)
+		return xen_pcibk_backend->add(pdev, dev, devid, publish_cb);
+	return -1;
+};
+static inline void xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
+					     struct pci_dev *dev)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->free)
+		return xen_pcibk_backend->release(pdev, dev);
+};
+
+static inline struct pci_dev *
+xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev, unsigned int domain,
+		      unsigned int bus, unsigned int devfn)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->get)
+		return xen_pcibk_backend->get(pdev, domain, bus, devfn);
+	return NULL;
+};
+/**
+* Add for domain0 PCIE-AER handling. Get guest domain/bus/devfn in xen_pcibk
+* before sending aer request to pcifront, so that guest could identify
+* device, coopearte with xen_pcibk to finish aer recovery job if device driver
+* has the capability
+*/
+static inline int xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
+					     struct xen_pcibk_device *pdev,
+					     unsigned int *domain,
+					     unsigned int *bus,
+					     unsigned int *devfn)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->find)
+		return xen_pcibk_backend->find(pcidev, pdev, domain, bus,
+					       devfn);
+	return -1;
+};
+static inline int xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->init)
+		return xen_pcibk_backend->init(pdev);
+	return -1;
+};
+static inline int xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
+					      publish_pci_root_cb cb)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->publish)
+		return xen_pcibk_backend->publish(pdev, cb);
+	return -1;
+};
+static inline void xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
+{
+	if (xen_pcibk_backend && xen_pcibk_backend->free)
+		return xen_pcibk_backend->free(pdev);
+};
+/* Handles events from front-end */
+irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id);
+void xen_pcibk_do_op(struct work_struct *data);
+
+int xen_pcibk_xenbus_register(void);
+void xen_pcibk_xenbus_unregister(void);
+
+extern int verbose_request;
+
+void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev);
+#endif
+
+/* Handles shared IRQs that can to device domain and control domain. */
+void xen_pcibk_irq_handler(struct pci_dev *dev, int reset);

drivers/xen/xen-pciback/vpci.c

+/*
+ * PCI Backend - Provides a Virtual PCI bus (with real devices)
+ *               to the frontend
+ *
+ *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include "pciback.h"
+
+#define PCI_SLOT_MAX 32
+#define DRV_NAME	"xen-pciback"
+
+struct vpci_dev_data {
+	/* Access to dev_list must be protected by lock */
+	struct list_head dev_list[PCI_SLOT_MAX];
+	spinlock_t lock;
+};
+
+static inline struct list_head *list_first(struct list_head *head)
+{
+	return head->next;
+}
+
+static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
+					       unsigned int domain,
+					       unsigned int bus,
+					       unsigned int devfn)
+{
+	struct pci_dev_entry *entry;
+	struct pci_dev *dev = NULL;
+	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
+	unsigned long flags;
+
+	if (domain != 0 || bus != 0)
+		return NULL;
+
+	if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
+		spin_lock_irqsave(&vpci_dev->lock, flags);
+
+		list_for_each_entry(entry,
+				    &vpci_dev->dev_list[PCI_SLOT(devfn)],
+				    list) {
+			if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
+				dev = entry->dev;
+				break;
+			}
+		}
+
+		spin_unlock_irqrestore(&vpci_dev->lock, flags);
+	}
+	return dev;
+}
+
+static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
+{
+	if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
+	    && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
+		return 1;
+
+	return 0;
+}
+
+static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
+				   struct pci_dev *dev, int devid,
+				   publish_pci_dev_cb publish_cb)
+{
+	int err = 0, slot, func = -1;
+	struct pci_dev_entry *t, *dev_entry;
+	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
+	unsigned long flags;
+
+	if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
+		err = -EFAULT;
+		xenbus_dev_fatal(pdev->xdev, err,
+				 "Can't export bridges on the virtual PCI bus");
+		goto out;
+	}
+
+	dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
+	if (!dev_entry) {
+		err = -ENOMEM;
+		xenbus_dev_fatal(pdev->xdev, err,
+				 "Error adding entry to virtual PCI bus");
+		goto out;
+	}
+
+	dev_entry->dev = dev;
+
+	spin_lock_irqsave(&vpci_dev->lock, flags);
+
+	/* Keep multi-function devices together on the virtual PCI bus */
+	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+		if (!list_empty(&vpci_dev->dev_list[slot])) {
+			t = list_entry(list_first(&vpci_dev->dev_list[slot]),
+				       struct pci_dev_entry, list);
+
+			if (match_slot(dev, t->dev)) {
+				pr_info(DRV_NAME ": vpci: %s: "
+					"assign to virtual slot %d func %d\n",
+					pci_name(dev), slot,
+					PCI_FUNC(dev->devfn));
+				list_add_tail(&dev_entry->list,
+					      &vpci_dev->dev_list[slot]);
+				func = PCI_FUNC(dev->devfn);
+				goto unlock;
+			}
+		}
+	}
+
+	/* Assign to a new slot on the virtual PCI bus */
+	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+		if (list_empty(&vpci_dev->dev_list[slot])) {
+			printk(KERN_INFO DRV_NAME
+			       ": vpci: %s: assign to virtual slot %d\n",
+			       pci_name(dev), slot);
+			list_add_tail(&dev_entry->list,
+				      &vpci_dev->dev_list[slot]);
+			func = PCI_FUNC(dev->devfn);
+			goto unlock;
+		}
+	}
+
+	err = -ENOMEM;
+	xenbus_dev_fatal(pdev->xdev, err,
+			 "No more space on root virtual PCI bus");
+
+unlock:
+	spin_unlock_irqrestore(&vpci_dev->lock, flags);
+
+	/* Publish this device. */
+	if (!err)
+		err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
+
+out:
+	return err;
+}
+
+static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
+					struct pci_dev *dev)
+{
+	int slot;
+	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
+	struct pci_dev *found_dev = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&vpci_dev->lock, flags);
+
+	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+		struct pci_dev_entry *e, *tmp;
+		list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
+					 list) {
+			if (e->dev == dev) {
+				list_del(&e->list);
+				found_dev = e->dev;
+				kfree(e);
+				goto out;
+			}
+		}
+	}
+
+out:
+	spin_unlock_irqrestore(&vpci_dev->lock, flags);
+
+	if (found_dev)
+		pcistub_put_pci_dev(found_dev);
+}
+
+static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
+{
+	int slot;
+	struct vpci_dev_data *vpci_dev;
+
+	vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
+	if (!vpci_dev)
+		return -ENOMEM;
+
+	spin_lock_init(&vpci_dev->lock);
+
+	for (slot = 0; slot < PCI_SLOT_MAX; slot++)
+		INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
+
+	pdev->pci_dev_data = vpci_dev;
+
+	return 0;
+}
+
+static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
+					 publish_pci_root_cb publish_cb)
+{
+	/* The Virtual PCI bus has only one root */
+	return publish_cb(pdev, 0, 0);
+}
+
+static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
+{
+	int slot;
+	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
+
+	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+		struct pci_dev_entry *e, *tmp;
+		list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
+					 list) {
+			list_del(&e->list);
+			pcistub_put_pci_dev(e->dev);
+			kfree(e);
+		}
+	}
+
+	kfree(vpci_dev);
+	pdev->pci_dev_data = NULL;
+}
+
+static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
+					struct xen_pcibk_device *pdev,
+					unsigned int *domain, unsigned int *bus,
+					unsigned int *devfn)
+{
+	struct pci_dev_entry *entry;
+	struct pci_dev *dev = NULL;
+	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
+	unsigned long flags;
+	int found = 0, slot;
+
+	spin_lock_irqsave(&vpci_dev->lock, flags);
+	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+		list_for_each_entry(entry,
+			    &vpci_dev->dev_list[slot],
+			    list) {
+			dev = entry->dev;
+			if (dev && dev->bus->number == pcidev->bus->number
+				&& pci_domain_nr(dev->bus) ==
+					pci_domain_nr(pcidev->bus)
+				&& dev->devfn == pcidev->devfn) {
+				found = 1;
+				*domain = 0;
+				*bus = 0;
+				*devfn = PCI_DEVFN(slot,
+					 PCI_FUNC(pcidev->devfn));
+			}
+		}
+	}
+	spin_unlock_irqrestore(&vpci_dev->lock, flags);
+	return found;
+}
+
+struct xen_pcibk_backend xen_pcibk_vpci_backend = {
+	.name		= "vpci",
+	.init		= __xen_pcibk_init_devices,
+	.free		= __xen_pcibk_release_devices,
+	.find		= __xen_pcibk_get_pcifront_dev,
+	.publish	= __xen_pcibk_publish_pci_roots,
+	.release	= __xen_pcibk_release_pci_dev,
+	.add		= __xen_pcibk_add_pci_dev,
+	.get		= __xen_pcibk_get_pci_dev,
+};