diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index fad3df2..8f84b10 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -62,4 +62,13 @@
 	 virtual environment, /sys/hypervisor will still be present,
 	 but will have no xen contents.
 
+config XEN_PLATFORM_PCI
+	tristate "xen platform pci device driver"
+	depends on XEN
+	default m
+	help
+	  Driver for the Xen PCI Platform device: it is responsible for
+	  initializing xenbus and grant_table when running in a Xen HVM
+	  domain. As a consequence this driver is required to run any Xen PV
+	  frontend on Xen HVM.
 endmenu
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 7c28434..e392fb7 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -9,4 +9,5 @@
 obj-$(CONFIG_XEN_BALLOON)	+= balloon.o
 obj-$(CONFIG_XEN_DEV_EVTCHN)	+= evtchn.o
 obj-$(CONFIG_XENFS)		+= xenfs/
-obj-$(CONFIG_XEN_SYS_HYPERVISOR)	+= sys-hypervisor.o
\ No newline at end of file
+obj-$(CONFIG_XEN_SYS_HYPERVISOR)	+= sys-hypervisor.o
+obj-$(CONFIG_XEN_PLATFORM_PCI)	+= platform-pci.o
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index d659480..7c64473 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -665,7 +665,7 @@
 
 		count = __get_cpu_var(xed_nesting_count);
 		__get_cpu_var(xed_nesting_count) = 0;
-	} while(count != 1);
+	} while (count != 1 || vcpu_info->evtchn_upcall_pending);
 
 out:
 
@@ -689,6 +689,7 @@
 {
 	__xen_evtchn_do_upcall();
 }
+EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
 
 /* Rebind a new event channel to an existing irq. */
 void rebind_evtchn_irq(int evtchn, int irq)
@@ -725,7 +726,10 @@
 	struct evtchn_bind_vcpu bind_vcpu;
 	int evtchn = evtchn_from_irq(irq);
 
-	if (!VALID_EVTCHN(evtchn))
+	/* events delivered via platform PCI interrupts are always
+	 * routed to vcpu 0 */
+	if (!VALID_EVTCHN(evtchn) ||
+		(xen_hvm_domain() && !xen_have_vector_callback))
 		return -1;
 
 	/* Send future instances of this interrupt to other vcpu. */
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index f66db3b..6c45318 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -37,11 +37,13 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/uaccess.h>
+#include <linux/io.h>
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
 #include <xen/page.h>
 #include <xen/grant_table.h>
+#include <xen/interface/memory.h>
 #include <asm/xen/hypercall.h>
 
 #include <asm/pgtable.h>
@@ -59,6 +61,8 @@
 static int gnttab_free_count;
 static grant_ref_t gnttab_free_head;
 static DEFINE_SPINLOCK(gnttab_list_lock);
+unsigned long xen_hvm_resume_frames;
+EXPORT_SYMBOL_GPL(xen_hvm_resume_frames);
 
 static struct grant_entry *shared;
 
@@ -433,7 +437,7 @@
 	return query.max_nr_frames;
 }
 
-static inline unsigned int max_nr_grant_frames(void)
+unsigned int gnttab_max_grant_frames(void)
 {
 	unsigned int xen_max = __max_nr_grant_frames();
 
@@ -441,6 +445,7 @@
 		return boot_max_nr_grant_frames;
 	return xen_max;
 }
+EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 
 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 {
@@ -449,6 +454,30 @@
 	unsigned int nr_gframes = end_idx + 1;
 	int rc;
 
+	if (xen_hvm_domain()) {
+		struct xen_add_to_physmap xatp;
+		unsigned int i = end_idx;
+		rc = 0;
+		/*
+		 * Loop backwards, so that the first hypercall has the largest
+		 * index, ensuring that the table will grow only once.
+		 */
+		do {
+			xatp.domid = DOMID_SELF;
+			xatp.idx = i;
+			xatp.space = XENMAPSPACE_grant_table;
+			xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
+			rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
+			if (rc != 0) {
+				printk(KERN_WARNING
+						"grant table add_to_physmap failed, err=%d\n", rc);
+				break;
+			}
+		} while (i-- > start_idx);
+
+		return rc;
+	}
+
 	frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
 	if (!frames)
 		return -ENOMEM;
@@ -465,7 +494,7 @@
 
 	BUG_ON(rc || setup.status);
 
-	rc = arch_gnttab_map_shared(frames, nr_gframes, max_nr_grant_frames(),
+	rc = arch_gnttab_map_shared(frames, nr_gframes, gnttab_max_grant_frames(),
 				    &shared);
 	BUG_ON(rc);
 
@@ -476,9 +505,27 @@
 
 int gnttab_resume(void)
 {
-	if (max_nr_grant_frames() < nr_grant_frames)
+	unsigned int max_nr_gframes;
+
+	max_nr_gframes = gnttab_max_grant_frames();
+	if (max_nr_gframes < nr_grant_frames)
 		return -ENOSYS;
-	return gnttab_map(0, nr_grant_frames - 1);
+
+	if (xen_pv_domain())
+		return gnttab_map(0, nr_grant_frames - 1);
+
+	if (!shared) {
+		shared = ioremap(xen_hvm_resume_frames, PAGE_SIZE * max_nr_gframes);
+		if (shared == NULL) {
+			printk(KERN_WARNING
+					"Failed to ioremap gnttab share frames!");
+			return -ENOMEM;
+		}
+	}
+
+	gnttab_map(0, nr_grant_frames - 1);
+
+	return 0;
 }
 
 int gnttab_suspend(void)
@@ -495,7 +542,7 @@
 	cur = nr_grant_frames;
 	extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) /
 		 GREFS_PER_GRANT_FRAME);
-	if (cur + extra > max_nr_grant_frames())
+	if (cur + extra > gnttab_max_grant_frames())
 		return -ENOSPC;
 
 	rc = gnttab_map(cur, cur + extra - 1);
@@ -505,15 +552,12 @@
 	return rc;
 }
 
-static int __devinit gnttab_init(void)
+int gnttab_init(void)
 {
 	int i;
 	unsigned int max_nr_glist_frames, nr_glist_frames;
 	unsigned int nr_init_grefs;
 
-	if (!xen_domain())
-		return -ENODEV;
-
 	nr_grant_frames = 1;
 	boot_max_nr_grant_frames = __max_nr_grant_frames();
 
@@ -556,5 +600,18 @@
 	kfree(gnttab_list);
 	return -ENOMEM;
 }
+EXPORT_SYMBOL_GPL(gnttab_init);
 
-core_initcall(gnttab_init);
+static int __devinit __gnttab_init(void)
+{
+	/* Delay grant-table initialization in the PV on HVM case */
+	if (xen_hvm_domain())
+		return 0;
+
+	if (!xen_pv_domain())
+		return -ENODEV;
+
+	return gnttab_init();
+}
+
+core_initcall(__gnttab_init);
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 07e857b..af9c559 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -264,5 +264,6 @@
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
 
 subsys_initcall(setup_shutdown_event);
diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
new file mode 100644
index 0000000..a0ee5d0
--- /dev/null
+++ b/drivers/xen/platform-pci.c
@@ -0,0 +1,181 @@
+/******************************************************************************
+ * platform-pci.c
+ *
+ * Xen platform PCI device driver
+ * Copyright (c) 2005, Intel Corporation.
+ * Copyright (c) 2007, XenSource Inc.
+ * Copyright (c) 2010, Citrix
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+
+#include <xen/grant_table.h>
+#include <xen/xenbus.h>
+#include <xen/events.h>
+#include <xen/hvm.h>
+
+#define DRV_NAME    "xen-platform-pci"
+
+MODULE_AUTHOR("ssmith@xensource.com and stefano.stabellini@eu.citrix.com");
+MODULE_DESCRIPTION("Xen platform PCI device");
+MODULE_LICENSE("GPL");
+
+static unsigned long platform_mmio;
+static unsigned long platform_mmio_alloc;
+static unsigned long platform_mmiolen;
+
+unsigned long alloc_xen_mmio(unsigned long len)
+{
+	unsigned long addr;
+
+	addr = platform_mmio + platform_mmio_alloc;
+	platform_mmio_alloc += len;
+	BUG_ON(platform_mmio_alloc > platform_mmiolen);
+
+	return addr;
+}
+
+static uint64_t get_callback_via(struct pci_dev *pdev)
+{
+	u8 pin;
+	int irq;
+
+	irq = pdev->irq;
+	if (irq < 16)
+		return irq; /* ISA IRQ */
+
+	pin = pdev->pin;
+
+	/* We don't know the GSI. Specify the PCI INTx line instead. */
+	return ((uint64_t)0x01 << 56) | /* PCI INTx identifier */
+		((uint64_t)pci_domain_nr(pdev->bus) << 32) |
+		((uint64_t)pdev->bus->number << 16) |
+		((uint64_t)(pdev->devfn & 0xff) << 8) |
+		((uint64_t)(pin - 1) & 3);
+}
+
+static irqreturn_t do_hvm_evtchn_intr(int irq, void *dev_id)
+{
+	xen_hvm_evtchn_do_upcall();
+	return IRQ_HANDLED;
+}
+
+static int xen_allocate_irq(struct pci_dev *pdev)
+{
+	return request_irq(pdev->irq, do_hvm_evtchn_intr,
+			IRQF_DISABLED | IRQF_NOBALANCING | IRQF_TRIGGER_RISING,
+			"xen-platform-pci", pdev);
+}
+
+static int __devinit platform_pci_init(struct pci_dev *pdev,
+				       const struct pci_device_id *ent)
+{
+	int i, ret;
+	long ioaddr, iolen;
+	long mmio_addr, mmio_len;
+	uint64_t callback_via;
+	unsigned int max_nr_gframes;
+
+	i = pci_enable_device(pdev);
+	if (i)
+		return i;
+
+	ioaddr = pci_resource_start(pdev, 0);
+	iolen = pci_resource_len(pdev, 0);
+
+	mmio_addr = pci_resource_start(pdev, 1);
+	mmio_len = pci_resource_len(pdev, 1);
+
+	if (mmio_addr == 0 || ioaddr == 0) {
+		dev_err(&pdev->dev, "no resources found\n");
+		ret = -ENOENT;
+		goto pci_out;
+	}
+
+	if (request_mem_region(mmio_addr, mmio_len, DRV_NAME) == NULL) {
+		dev_err(&pdev->dev, "MEM I/O resource 0x%lx @ 0x%lx busy\n",
+		       mmio_addr, mmio_len);
+		ret = -EBUSY;
+		goto pci_out;
+	}
+
+	if (request_region(ioaddr, iolen, DRV_NAME) == NULL) {
+		dev_err(&pdev->dev, "I/O resource 0x%lx @ 0x%lx busy\n",
+		       iolen, ioaddr);
+		ret = -EBUSY;
+		goto mem_out;
+	}
+
+	platform_mmio = mmio_addr;
+	platform_mmiolen = mmio_len;
+
+	if (!xen_have_vector_callback) {
+		ret = xen_allocate_irq(pdev);
+		if (ret) {
+			dev_warn(&pdev->dev, "request_irq failed err=%d\n", ret);
+			goto out;
+		}
+		callback_via = get_callback_via(pdev);
+		ret = xen_set_callback_via(callback_via);
+		if (ret) {
+			dev_warn(&pdev->dev, "Unable to set the evtchn callback "
+					 "err=%d\n", ret);
+			goto out;
+		}
+	}
+
+	max_nr_gframes = gnttab_max_grant_frames();
+	xen_hvm_resume_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
+	ret = gnttab_init();
+	if (ret)
+		goto out;
+	xenbus_probe(NULL);
+	return 0;
+
+out:
+	release_region(ioaddr, iolen);
+mem_out:
+	release_mem_region(mmio_addr, mmio_len);
+pci_out:
+	pci_disable_device(pdev);
+	return ret;
+}
+
+static struct pci_device_id platform_pci_tbl[] __devinitdata = {
+	{PCI_VENDOR_ID_XEN, PCI_DEVICE_ID_XEN_PLATFORM,
+		PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
+	{0,}
+};
+
+MODULE_DEVICE_TABLE(pci, platform_pci_tbl);
+
+static struct pci_driver platform_driver = {
+	.name =           DRV_NAME,
+	.probe =          platform_pci_init,
+	.id_table =       platform_pci_tbl,
+};
+
+static int __init platform_pci_module_init(void)
+{
+	return pci_register_driver(&platform_driver);
+}
+
+module_init(platform_pci_module_init);
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index d96fa75b..a9e83c4 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -781,8 +781,23 @@
 	/* Notify others that xenstore is up */
 	blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 }
+EXPORT_SYMBOL_GPL(xenbus_probe);
 
-static int __init xenbus_probe_init(void)
+static int __init xenbus_probe_initcall(void)
+{
+	if (!xen_domain())
+		return -ENODEV;
+
+	if (xen_initial_domain() || xen_hvm_domain())
+		return 0;
+
+	xenbus_probe(NULL);
+	return 0;
+}
+
+device_initcall(xenbus_probe_initcall);
+
+static int __init xenbus_init(void)
 {
 	int err = 0;
 
@@ -834,9 +849,6 @@
 		goto out_unreg_back;
 	}
 
-	if (!xen_initial_domain())
-		xenbus_probe(NULL);
-
 #ifdef CONFIG_XEN_COMPAT_XENFS
 	/*
 	 * Create xenfs mountpoint in /proc for compatibility with
@@ -857,7 +869,7 @@
 	return err;
 }
 
-postcore_initcall(xenbus_probe_init);
+postcore_initcall(xenbus_init);
 
 MODULE_LICENSE("GPL");
 
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 3bedcc1..cca2526 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -2772,3 +2772,6 @@
 #define PCI_DEVICE_ID_RME_DIGI32	0x9896
 #define PCI_DEVICE_ID_RME_DIGI32_PRO	0x9897
 #define PCI_DEVICE_ID_RME_DIGI32_8	0x9898
+
+#define PCI_VENDOR_ID_XEN		0x5853
+#define PCI_DEVICE_ID_XEN_PLATFORM	0x0001
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index a40f1cd..9a73170 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -51,6 +51,7 @@
 	u16 count;
 };
 
+int gnttab_init(void);
 int gnttab_suspend(void);
 int gnttab_resume(void);
 
@@ -112,6 +113,9 @@
 void arch_gnttab_unmap_shared(struct grant_entry *shared,
 			      unsigned long nr_gframes);
 
+extern unsigned long xen_hvm_resume_frames;
+unsigned int gnttab_max_grant_frames(void);
+
 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
 
 #endif /* __ASM_GNTTAB_H__ */
diff --git a/include/xen/interface/grant_table.h b/include/xen/interface/grant_table.h
index 39da93c..39e5717 100644
--- a/include/xen/interface/grant_table.h
+++ b/include/xen/interface/grant_table.h
@@ -28,6 +28,7 @@
 #ifndef __XEN_PUBLIC_GRANT_TABLE_H__
 #define __XEN_PUBLIC_GRANT_TABLE_H__
 
+#include <xen/interface/xen.h>
 
 /***********************************
  * GRANT TABLE REPRESENTATION