[PATCH V5 01/15] ACPI: MCFG: Move mmcfg_list management to drivers/acpi

[Tomasz Nowicki <tn@semihalf.com>]

From: Jayachandran C <jchandra@broadcom.com>

Move pci_mmcfg_list handling to a drivers/acpi/pci_mcfg.c. This is
to share the API and code with ARM64 later. The corresponding
declarations are moved from asm/pci_x86.h to linux/pci-acpi.h

As a part of this we introduce three functions that can be
implemented by the arch code: pci_mmconfig_map_resource() to map a
mcfg entry, pci_mmconfig_unmap_resource to do the corresponding
unmap and pci_mmconfig_enabled to see if the arch setup of
mcfg entries was successful. We also provide weak implementations
of these, which will be used from ARM64. On x86, we retain the
old logic by providing platform specific implementation.

This patch is purely rearranging code, it should not have any
impact on the logic of MCFG parsing or list handling.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
[Xen parts:]
Acked-by: David Vrabel <david.vrabel@citrix.com>
---
 arch/x86/include/asm/pci_x86.h |  24 +---
 arch/x86/pci/mmconfig-shared.c | 269 +++++------------------------------
 arch/x86/pci/mmconfig_32.c     |   1 +
 arch/x86/pci/mmconfig_64.c     |   1 +
 arch/x86/pci/numachip.c        |   1 +
 drivers/acpi/Makefile          |   1 +
 drivers/acpi/pci_mcfg.c        | 312 +++++++++++++++++++++++++++++++++++++++++
 drivers/xen/pci.c              |   5 +-
 include/linux/pci-acpi.h       |  33 +++++
 9 files changed, 386 insertions(+), 261 deletions(-)
 create mode 100644 drivers/acpi/pci_mcfg.c

diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 46873fb..7824626 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -122,33 +122,11 @@ extern int pci_legacy_init(void);
 extern void pcibios_fixup_irqs(void);
 
 /* pci-mmconfig.c */
-
-/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
-#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
-
-struct pci_mmcfg_region {
-	struct list_head list;
-	struct resource res;
-	u64 address;
-	char __iomem *virt;
-	u16 segment;
-	u8 start_bus;
-	u8 end_bus;
-	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
-};
-
+struct pci_mmcfg_region;
 extern int __init pci_mmcfg_arch_init(void);
 extern void __init pci_mmcfg_arch_free(void);
 extern int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg);
 extern void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg);
-extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
-			       phys_addr_t addr);
-extern int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
-extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
-
-extern struct list_head pci_mmcfg_list;
-
-#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
 
 /*
  * On AMD Fam10h CPUs, all PCI MMIO configuration space accesses must use
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index dd30b7e..626710b 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -12,13 +12,12 @@
 
 #include <linux/pci.h>
 #include <linux/init.h>
-#include <linux/sfi_acpi.h>
 #include <linux/bitmap.h>
-#include <linux/dmi.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/rculist.h>
 #include <asm/e820.h>
+#include <linux/pci-acpi.h>
 #include <asm/pci_x86.h>
 #include <asm/acpi.h>
 
@@ -27,9 +26,6 @@
 /* Indicate if the mmcfg resources have been placed into the resource table. */
 static bool pci_mmcfg_running_state;
 static bool pci_mmcfg_arch_init_failed;
-static DEFINE_MUTEX(pci_mmcfg_lock);
-
-LIST_HEAD(pci_mmcfg_list);
 
 static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
 {
@@ -48,83 +44,6 @@ static void __init free_all_mmcfg(void)
 		pci_mmconfig_remove(cfg);
 }
 
-static void list_add_sorted(struct pci_mmcfg_region *new)
-{
-	struct pci_mmcfg_region *cfg;
-
-	/* keep list sorted by segment and starting bus number */
-	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
-		if (cfg->segment > new->segment ||
-		    (cfg->segment == new->segment &&
-		     cfg->start_bus >= new->start_bus)) {
-			list_add_tail_rcu(&new->list, &cfg->list);
-			return;
-		}
-	}
-	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
-}
-
-static struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
-						   int end, u64 addr)
-{
-	struct pci_mmcfg_region *new;
-	struct resource *res;
-
-	if (addr == 0)
-		return NULL;
-
-	new = kzalloc(sizeof(*new), GFP_KERNEL);
-	if (!new)
-		return NULL;
-
-	new->address = addr;
-	new->segment = segment;
-	new->start_bus = start;
-	new->end_bus = end;
-
-	res = &new->res;
-	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
-	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
-	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
-	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
-		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
-	res->name = new->name;
-
-	return new;
-}
-
-static struct pci_mmcfg_region *__init pci_mmconfig_add(int segment, int start,
-							int end, u64 addr)
-{
-	struct pci_mmcfg_region *new;
-
-	new = pci_mmconfig_alloc(segment, start, end, addr);
-	if (new) {
-		mutex_lock(&pci_mmcfg_lock);
-		list_add_sorted(new);
-		mutex_unlock(&pci_mmcfg_lock);
-
-		pr_info(PREFIX
-		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
-		       "(base %#lx)\n",
-		       segment, start, end, &new->res, (unsigned long)addr);
-	}
-
-	return new;
-}
-
-struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
-{
-	struct pci_mmcfg_region *cfg;
-
-	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
-		if (cfg->segment == segment &&
-		    cfg->start_bus <= bus && bus <= cfg->end_bus)
-			return cfg;
-
-	return NULL;
-}
-
 static const char *__init pci_mmcfg_e7520(void)
 {
 	u32 win;
@@ -543,73 +462,6 @@ static void __init pci_mmcfg_reject_broken(int early)
 	}
 }
 
-static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
-					struct acpi_mcfg_allocation *cfg)
-{
-	int year;
-
-	if (cfg->address < 0xFFFFFFFF)
-		return 0;
-
-	if (!strncmp(mcfg->header.oem_id, "SGI", 3))
-		return 0;
-
-	if (mcfg->header.revision >= 1) {
-		if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) &&
-		    year >= 2010)
-			return 0;
-	}
-
-	pr_err(PREFIX "MCFG region for %04x [bus %02x-%02x] at %#llx "
-	       "is above 4GB, ignored\n", cfg->pci_segment,
-	       cfg->start_bus_number, cfg->end_bus_number, cfg->address);
-	return -EINVAL;
-}
-
-static int __init pci_parse_mcfg(struct acpi_table_header *header)
-{
-	struct acpi_table_mcfg *mcfg;
-	struct acpi_mcfg_allocation *cfg_table, *cfg;
-	unsigned long i;
-	int entries;
-
-	if (!header)
-		return -EINVAL;
-
-	mcfg = (struct acpi_table_mcfg *)header;
-
-	/* how many config structures do we have */
-	free_all_mmcfg();
-	entries = 0;
-	i = header->length - sizeof(struct acpi_table_mcfg);
-	while (i >= sizeof(struct acpi_mcfg_allocation)) {
-		entries++;
-		i -= sizeof(struct acpi_mcfg_allocation);
-	}
-	if (entries == 0) {
-		pr_err(PREFIX "MMCONFIG has no entries\n");
-		return -ENODEV;
-	}
-
-	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
-	for (i = 0; i < entries; i++) {
-		cfg = &cfg_table[i];
-		if (acpi_mcfg_check_entry(mcfg, cfg)) {
-			free_all_mmcfg();
-			return -ENODEV;
-		}
-
-		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
-				   cfg->end_bus_number, cfg->address) == NULL) {
-			pr_warn(PREFIX "no memory for MCFG entries\n");
-			free_all_mmcfg();
-			return -ENOMEM;
-		}
-	}
-
-	return 0;
-}
-
 #ifdef CONFIG_ACPI_APEI
 extern int (*arch_apei_filter_addr)(int (*func)(__u64 start, __u64 size,
 				     void *data), void *data);
@@ -662,13 +514,20 @@ static void __init __pci_mmcfg_init(int early)
 
 static int __initdata known_bridge;
 
+static void __init pci_mmcfg_list_setup(void)
+{
+	free_all_mmcfg();
+	if (pci_mmconfig_parse_table())
+		free_all_mmcfg();
+}
+
 void __init pci_mmcfg_early_init(void)
 {
 	if (pci_probe & PCI_PROBE_MMCONF) {
 		if (pci_mmcfg_check_hostbridge())
 			known_bridge = 1;
 		else
-			acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
+			pci_mmcfg_list_setup();
 		__pci_mmcfg_init(1);
 
 		set_apei_filter();
@@ -686,7 +545,7 @@ void __init pci_mmcfg_late_init(void)
 
 	/* MMCONFIG hasn't been enabled yet, try again */
 	if (pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF) {
-		acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
+		pci_mmcfg_list_setup();
 		__pci_mmcfg_init(0);
 	}
 }
@@ -720,99 +579,41 @@ static int __init pci_mmcfg_late_insert_resources(void)
  */
 late_initcall(pci_mmcfg_late_insert_resources);
 
-/* Add MMCFG information for host bridges */
-int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
-			phys_addr_t addr)
+int pci_mmconfig_map_resource(struct device *dev, struct pci_mmcfg_region *cfg)
 {
-	int rc;
-	struct resource *tmp = NULL;
-	struct pci_mmcfg_region *cfg;
+	struct resource *tmp;
 
-	if (!(pci_probe & PCI_PROBE_MMCONF) || pci_mmcfg_arch_init_failed)
-		return -ENODEV;
-
-	if (start > end)
-		return -EINVAL;
-
-	mutex_lock(&pci_mmcfg_lock);
-	cfg = pci_mmconfig_lookup(seg, start);
-	if (cfg) {
-		if (cfg->end_bus < end)
-			dev_info(dev, FW_INFO
-				 "MMCONFIG for "
-				 "domain %04x [bus %02x-%02x] "
-				 "only partially covers this bridge\n",
-				  cfg->segment, cfg->start_bus, cfg->end_bus);
-		mutex_unlock(&pci_mmcfg_lock);
-		return -EEXIST;
-	}
-
-	if (!addr) {
-		mutex_unlock(&pci_mmcfg_lock);
-		return -EINVAL;
-	}
-
-	rc = -EBUSY;
-	cfg = pci_mmconfig_alloc(seg, start, end, addr);
-	if (cfg == NULL) {
-		dev_warn(dev, "fail to add MMCONFIG (out of memory)\n");
-		rc = -ENOMEM;
-	} else if (!pci_mmcfg_check_reserved(dev, cfg, 0)) {
+	if (!pci_mmcfg_check_reserved(dev, cfg, 0)) {
 		dev_warn(dev, FW_BUG "MMCONFIG %pR isn't reserved\n",
 			 &cfg->res);
-	} else {
-		/* Insert resource if it's not in boot stage */
-		if (pci_mmcfg_running_state)
-			tmp = insert_resource_conflict(&iomem_resource,
-						       &cfg->res);
-
+		return -EBUSY;
+	}
+	/* Insert resource if it's not in boot stage */
+	if (pci_mmcfg_running_state) {
+		tmp = insert_resource_conflict(&iomem_resource,
+					       &cfg->res);
 		if (tmp) {
-			dev_warn(dev,
-				 "MMCONFIG %pR conflicts with "
-				 "%s %pR\n",
-				 &cfg->res, tmp->name, tmp);
-		} else if (pci_mmcfg_arch_map(cfg)) {
-			dev_warn(dev, "fail to map MMCONFIG %pR.\n",
-				 &cfg->res);
-		} else {
-			list_add_sorted(cfg);
-			dev_info(dev, "MMCONFIG at %pR (base %#lx)\n",
-				 &cfg->res, (unsigned long)addr);
-			cfg = NULL;
-			rc = 0;
+			dev_warn(dev, "MMCONFIG %pR conflicts with %s %pR\n",
+				&cfg->res, tmp->name, tmp);
+			return -EBUSY;
 		}
 	}
-
-	if (cfg) {
-		if (cfg->res.parent)
-			release_resource(&cfg->res);
-		kfree(cfg);
+	if (pci_mmcfg_arch_map(cfg)) {
+		dev_warn(dev, "fail to map MMCONFIG %pR.\n", &cfg->res);
+		return -EBUSY;
 	}
-
-	mutex_unlock(&pci_mmcfg_lock);
-
-	return rc;
+	return 0;
 }
 
-/* Delete MMCFG information for host bridges */
-int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
+void pci_mmconfig_unmap_resource(struct pci_mmcfg_region *cfg)
 {
-	struct pci_mmcfg_region *cfg;
-
-	mutex_lock(&pci_mmcfg_lock);
-	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
-		if (cfg->segment == seg && cfg->start_bus == start &&
-		    cfg->end_bus == end) {
-			list_del_rcu(&cfg->list);
-			synchronize_rcu();
-			pci_mmcfg_arch_unmap(cfg);
-			if (cfg->res.parent)
-				release_resource(&cfg->res);
-			mutex_unlock(&pci_mmcfg_lock);
-			kfree(cfg);
-			return 0;
-		}
-	mutex_unlock(&pci_mmcfg_lock);
+	pci_mmcfg_arch_unmap(cfg);
+	if (cfg->res.parent)
+		release_resource(&cfg->res);
+	cfg->res.parent = NULL;
+}
 
-	return -ENOENT;
+int pci_mmconfig_enabled(void)
+{
+	return (pci_probe & PCI_PROBE_MMCONF) && !pci_mmcfg_arch_init_failed;
 }
diff --git a/arch/x86/pci/mmconfig_32.c b/arch/x86/pci/mmconfig_32.c
index 43984bc..38a37f8 100644
--- a/arch/x86/pci/mmconfig_32.c
+++ b/arch/x86/pci/mmconfig_32.c
@@ -12,6 +12,7 @@
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/rcupdate.h>
+#include <linux/pci-acpi.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
 
diff --git a/arch/x86/pci/mmconfig_64.c b/arch/x86/pci/mmconfig_64.c
index bea5249..29253ec 100644
--- a/arch/x86/pci/mmconfig_64.c
+++ b/arch/x86/pci/mmconfig_64.c
@@ -10,6 +10,7 @@
 #include <linux/acpi.h>
 #include <linux/bitmap.h>
 #include <linux/rcupdate.h>
+#include <linux/pci-acpi.h>
 #include <asm/e820.h>
 #include <asm/pci_x86.h>
 
diff --git a/arch/x86/pci/numachip.c b/arch/x86/pci/numachip.c
index 2e565e6..c181eeb 100644
--- a/arch/x86/pci/numachip.c
+++ b/arch/x86/pci/numachip.c
@@ -14,6 +14,7 @@
  */
 
 #include <linux/pci.h>
+#include <linux/pci-acpi.h>
 #include <asm/pci_x86.h>
 
 static u8 limit __read_mostly;
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 7ea903d..e5e4393 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -40,6 +40,7 @@ acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o
 acpi-y				+= ec.o
 acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
 acpi-y				+= pci_root.o pci_link.o pci_irq.o
+acpi-$(CONFIG_PCI_MMCONFIG)	+= pci_mcfg.o
 acpi-y				+= acpi_lpss.o acpi_apd.o
 acpi-y				+= acpi_platform.o
 acpi-y				+= acpi_pnp.o
diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
new file mode 100644
index 0000000..ea84365
--- /dev/null
+++ b/drivers/acpi/pci_mcfg.c
@@ -0,0 +1,312 @@
+/*
+ * pci_mcfg.c
+ *
+ * Common code to maintain the MCFG areas and mappings
+ *
+ * This has been extracted from arch/x86/pci/mmconfig-shared.c
+ * and moved here so that other architectures can use this code.
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/dmi.h>
+#include <linux/pci-acpi.h>
+#include <linux/sfi_acpi.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/rculist.h>
+
+#define PREFIX	"ACPI: "
+
+static DEFINE_MUTEX(pci_mmcfg_lock);
+LIST_HEAD(pci_mmcfg_list);
+
+static void list_add_sorted(struct pci_mmcfg_region *new)
+{
+	struct pci_mmcfg_region *cfg;
+
+	/* keep list sorted by segment and starting bus number */
+	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
+		if (cfg->segment > new->segment ||
+		    (cfg->segment == new->segment &&
+		     cfg->start_bus >= new->start_bus)) {
+			list_add_tail_rcu(&new->list, &cfg->list);
+			return;
+		}
+	}
+	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
+}
+
+static struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
+						   int end, u64 addr)
+{
+	struct pci_mmcfg_region *new;
+	struct resource *res;
+
+	if (addr == 0)
+		return NULL;
+
+	new = kzalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	new->address = addr;
+	new->segment = segment;
+	new->start_bus = start;
+	new->end_bus = end;
+
+	res = &new->res;
+	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
+	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
+	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
+		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
+	res->name = new->name;
+
+	return new;
+}
+
+struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
+							int end, u64 addr)
+{
+	struct pci_mmcfg_region *new;
+
+	new = pci_mmconfig_alloc(segment, start, end, addr);
+	if (new) {
+		mutex_lock(&pci_mmcfg_lock);
+		list_add_sorted(new);
+		mutex_unlock(&pci_mmcfg_lock);
+
+		pr_info(PREFIX
+		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
+		       "(base %#lx)\n",
+		       segment, start, end, &new->res, (unsigned long)addr);
+	}
+
+	return new;
+}
+
+struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
+{
+	struct pci_mmcfg_region *cfg;
+
+	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+		if (cfg->segment == segment &&
+		    cfg->start_bus <= bus && bus <= cfg->end_bus)
+			return cfg;
+
+	return NULL;
+}
+
+/*
+ * Map a pci_mmcfg_region, can be overrriden by arch
+ */
+int __weak pci_mmconfig_map_resource(struct device *dev,
+	struct pci_mmcfg_region *mcfg)
+{
+	struct resource *tmp;
+	void __iomem *vaddr;
+
+	tmp = insert_resource_conflict(&iomem_resource, &mcfg->res);
+	if (tmp) {
+		dev_warn(dev, "MMCONFIG %pR conflicts with %s %pR\n",
+			&mcfg->res, tmp->name, tmp);
+		return -EBUSY;
+	}
+
+	vaddr =  ioremap(mcfg->res.start, resource_size(&mcfg->res));
+	if (!vaddr) {
+		release_resource(&mcfg->res);
+		return -ENOMEM;
+	}
+
+	mcfg->virt = vaddr;
+	return 0;
+}
+
+/*
+ * Unmap a pci_mmcfg_region, can be overrriden by arch
+ */
+void __weak pci_mmconfig_unmap_resource(struct pci_mmcfg_region *mcfg)
+{
+	if (mcfg->virt) {
+		iounmap(mcfg->virt);
+		mcfg->virt = NULL;
+	}
+	if (mcfg->res.parent) {
+		release_resource(&mcfg->res);
+		mcfg->res.parent = NULL;
+	}
+}
+
+/*
+ * check if the mmconfig is enabled and configured
+ */
+int __weak pci_mmconfig_enabled(void)
+{
+	return 1;
+}
+
+/* Add MMCFG information for host bridges */
+int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
+			phys_addr_t addr)
+{
+	struct pci_mmcfg_region *cfg;
+	int rc;
+
+	if (!pci_mmconfig_enabled())
+		return -ENODEV;
+	if (start > end)
+		return -EINVAL;
+
+	mutex_lock(&pci_mmcfg_lock);
+	cfg = pci_mmconfig_lookup(seg, start);
+	if (cfg) {
+		if (cfg->end_bus < end)
+			dev_info(dev, FW_INFO
+				 "MMCONFIG for "
+				 "domain %04x [bus %02x-%02x] "
+				 "only partially covers this bridge\n",
+				  cfg->segment, cfg->start_bus, cfg->end_bus);
+		rc = -EEXIST;
+		goto err;
+	}
+
+	if (!addr) {
+		rc = -EINVAL;
+		goto err;
+	}
+
+	cfg = pci_mmconfig_alloc(seg, start, end, addr);
+	if (cfg == NULL) {
+		dev_warn(dev, "fail to add MMCONFIG (out of memory)\n");
+		rc = -ENOMEM;
+		goto err;
+	}
+	rc = pci_mmconfig_map_resource(dev, cfg);
+	if (!rc) {
+		list_add_sorted(cfg);
+		dev_info(dev, "MMCONFIG at %pR (base %#lx)\n",
+				 &cfg->res, (unsigned long)addr);
+		return 0;
+	} else {
+		if (cfg->res.parent)
+			release_resource(&cfg->res);
+		kfree(cfg);
+	}
+
+err:
+	mutex_unlock(&pci_mmcfg_lock);
+	return rc;
+}
+
+/* Delete MMCFG information for host bridges */
+int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
+{
+	struct pci_mmcfg_region *cfg;
+
+	mutex_lock(&pci_mmcfg_lock);
+	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+		if (cfg->segment == seg && cfg->start_bus == start &&
+		    cfg->end_bus == end) {
+			list_del_rcu(&cfg->list);
+			synchronize_rcu();
+			pci_mmconfig_unmap_resource(cfg);
+			mutex_unlock(&pci_mmcfg_lock);
+			kfree(cfg);
+			return 0;
+		}
+	mutex_unlock(&pci_mmcfg_lock);
+
+	return -ENOENT;
+}
+
+static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
+					struct acpi_mcfg_allocation *cfg)
+{
+	int year;
+
+	if (!config_enabled(CONFIG_X86))
+		return 0;
+
+	if (cfg->address < 0xFFFFFFFF)
+		return 0;
+
+	if (!strncmp(mcfg->header.oem_id, "SGI", 3))
+		return 0;
+
+	if (mcfg->header.revision >= 1) {
+		if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) &&
+		    year >= 2010)
+			return 0;
+	}
+
+	pr_err(PREFIX "MCFG region for %04x [bus %02x-%02x] at %#llx "
+	       "is above 4GB, ignored\n", cfg->pci_segment,
+	       cfg->start_bus_number, cfg->end_bus_number, cfg->address);
+	return -EINVAL;
+}
+
+static int __init pci_parse_mcfg(struct acpi_table_header *header)
+{
+	struct acpi_table_mcfg *mcfg;
+	struct acpi_mcfg_allocation *cfg_table, *cfg;
+	unsigned long i;
+	int entries;
+
+	if (!header)
+		return -EINVAL;
+
+	mcfg = (struct acpi_table_mcfg *)header;
+
+	/* how many config structures do we have */
+	entries = 0;
+	i = header->length - sizeof(struct acpi_table_mcfg);
+	while (i >= sizeof(struct acpi_mcfg_allocation)) {
+		entries++;
+		i -= sizeof(struct acpi_mcfg_allocation);
+	}
+	if (entries == 0) {
+		pr_err(PREFIX "MMCONFIG has no entries\n");
+		return -ENODEV;
+	}
+
+	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
+	for (i = 0; i < entries; i++) {
+		cfg = &cfg_table[i];
+		if (acpi_mcfg_check_entry(mcfg, cfg))
+			return -ENODEV;
+
+		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
+				   cfg->end_bus_number, cfg->address) == NULL) {
+			pr_warn(PREFIX "no memory for MCFG entries\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+int __init pci_mmconfig_parse_table(void)
+{
+	return acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
+}
+
+void __weak __init pci_mmcfg_late_init(void)
+{
+	int err, n = 0;
+	struct pci_mmcfg_region *cfg;
+
+	err = pci_mmconfig_parse_table();
+	if (err) {
+		pr_err(PREFIX " Failed to parse MCFG (%d)\n", err);
+		return;
+	}
+
+	list_for_each_entry(cfg, &pci_mmcfg_list, list) {
+		pci_mmconfig_map_resource(NULL, cfg);
+		n++;
+	}
+
+	pr_info(PREFIX " MCFG table loaded %d entries\n", n);
+}
diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index 7494dbe..97aa9d3 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -27,9 +27,6 @@
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
 #include "../pci/pci.h"
-#ifdef CONFIG_PCI_MMCONFIG
-#include <asm/pci_x86.h>
-#endif
 
 static bool __read_mostly pci_seg_supported = true;
 
@@ -221,7 +218,7 @@ static int __init xen_mcfg_late(void)
 	if (!xen_initial_domain())
 		return 0;
 
-	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
+	if (!pci_mmconfig_enabled())
 		return 0;
 
 	if (list_empty(&pci_mmcfg_list))
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 89ab057..e9450ef 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -106,6 +106,39 @@ extern const u8 pci_acpi_dsm_uuid[];
 #define RESET_DELAY_DSM		0x08
 #define FUNCTION_DELAY_DSM	0x09
 
+/* common API to maintain list of MCFG regions */
+/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
+#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
+
+struct pci_mmcfg_region {
+	struct list_head list;
+	struct resource res;
+	u64 address;
+	char __iomem *virt;
+	u16 segment;
+	u8 start_bus;
+	u8 end_bus;
+	char name[PCI_MMCFG_RESOURCE_NAME_LEN];
+};
+
+extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
+			       phys_addr_t addr);
+extern int pci_mmconfig_delete(u16 seg, u8 start, u8 end);
+
+extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
+extern struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
+							int end, u64 addr);
+extern int pci_mmconfig_map_resource(struct device *dev,
+	struct pci_mmcfg_region *mcfg);
+extern void pci_mmconfig_unmap_resource(struct pci_mmcfg_region *mcfg);
+extern int pci_mmconfig_enabled(void);
+extern int __init pci_mmconfig_parse_table(void);
+
+extern struct list_head pci_mmcfg_list;
+
+#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
+#define PCI_MMCFG_OFFSET(bus, devfn)   ((bus) << 20 | (devfn) << 12)
+
 #else	/* CONFIG_ACPI */
 static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
 static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
-- 
1.9.1