10 files changed, 503 insertions, 50 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index fad3df2c1276..0a8826936639 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -62,4 +62,13 @@ config XEN_SYS_HYPERVISOR
          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_PVHVM
+        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 7c284342f30f..e392fb776af3 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -9,4 +9,5 @@ obj-$(CONFIG_XEN_XENCOMM)	+= xencomm.o
 obj-$(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 28f133ae76ad..72f91bff29c7 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -29,6 +29,7 @@
 #include <linux/bootmem.h>
 #include <linux/slab.h>
 
+#include <asm/desc.h>
 #include <asm/ptrace.h>
 #include <asm/irq.h>
 #include <asm/idle.h>
@@ -36,10 +37,14 @@
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
 
+#include <xen/xen.h>
+#include <xen/hvm.h>
 #include <xen/xen-ops.h>
 #include <xen/events.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/event_channel.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/hvm/params.h>
 
 /*
  * This lock protects updates to the following mapping and reference-count
@@ -335,9 +340,18 @@ static int find_unbound_irq(void)
         int irq;
         struct irq_desc *desc;
 
-        for (irq = 0; irq < nr_irqs; irq++)
+        for (irq = 0; irq < nr_irqs; irq++) {
+                desc = irq_to_desc(irq);
+                /* only 0->15 have init'd desc; handle irq > 16 */
+                if (desc == NULL)
+                        break;
+                if (desc->chip == &no_irq_chip)
+                        break;
+                if (desc->chip != &xen_dynamic_chip)
+                        continue;
                 if (irq_info[irq].type == IRQT_UNBOUND)
                         break;
+        }
 
         if (irq == nr_irqs)
                 panic("No available IRQ to bind to: increase nr_irqs!\n");
@@ -346,7 +360,7 @@ static int find_unbound_irq(void)
         if (WARN_ON(desc == NULL))
                 return -1;
 
-        dynamic_irq_init(irq);
+        dynamic_irq_init_keep_chip_data(irq);
 
         return irq;
 }
@@ -618,17 +632,13 @@ static DEFINE_PER_CPU(unsigned, xed_nesting_count);
  * a bitset of words which contain pending event bits.  The second
  * level is a bitset of pending events themselves.
  */
-void xen_evtchn_do_upcall(struct pt_regs *regs)
+static void __xen_evtchn_do_upcall(void)
 {
         int cpu = get_cpu();
-        struct pt_regs *old_regs = set_irq_regs(regs);
         struct shared_info *s = HYPERVISOR_shared_info;
         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
         unsigned count;
 
-        exit_idle();
-        irq_enter();
-
         do {
                 unsigned long pending_words;
 
@@ -665,14 +675,31 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 
                 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:
+
+        put_cpu();
+}
+
+void xen_evtchn_do_upcall(struct pt_regs *regs)
+{
+        struct pt_regs *old_regs = set_irq_regs(regs);
+
+        exit_idle();
+        irq_enter();
+
+        __xen_evtchn_do_upcall();
+
         irq_exit();
         set_irq_regs(old_regs);
+}
 
-        put_cpu();
+void xen_hvm_evtchn_do_upcall(void)
+{
+        __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)
@@ -709,7 +736,10 @@ static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
         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. */
@@ -934,6 +964,44 @@ static struct irq_chip xen_dynamic_chip __read_mostly = {
         .retrigger      = retrigger_dynirq,
 };
 
+int xen_set_callback_via(uint64_t via)
+{
+        struct xen_hvm_param a;
+        a.domid = DOMID_SELF;
+        a.index = HVM_PARAM_CALLBACK_IRQ;
+        a.value = via;
+        return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
+}
+EXPORT_SYMBOL_GPL(xen_set_callback_via);
+
+#ifdef CONFIG_XEN_PVHVM
+/* Vector callbacks are better than PCI interrupts to receive event
+ * channel notifications because we can receive vector callbacks on any
+ * vcpu and we don't need PCI support or APIC interactions. */
+void xen_callback_vector(void)
+{
+        int rc;
+        uint64_t callback_via;
+        if (xen_have_vector_callback) {
+                callback_via = HVM_CALLBACK_VECTOR(XEN_HVM_EVTCHN_CALLBACK);
+                rc = xen_set_callback_via(callback_via);
+                if (rc) {
+                        printk(KERN_ERR "Request for Xen HVM callback vector"
+                                        " failed.\n");
+                        xen_have_vector_callback = 0;
+                        return;
+                }
+                printk(KERN_INFO "Xen HVM callback vector for event delivery is "
+                                "enabled\n");
+                /* in the restore case the vector has already been allocated */
+                if (!test_bit(XEN_HVM_EVTCHN_CALLBACK, used_vectors))
+                        alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, xen_hvm_callback_vector);
+        }
+}
+#else
+void xen_callback_vector(void) {}
+#endif
+
 void __init xen_init_IRQ(void)
 {
         int i;
@@ -948,5 +1016,10 @@ void __init xen_init_IRQ(void)
         for (i = 0; i < NR_EVENT_CHANNELS; i++)
                 mask_evtchn(i);
 
-        irq_ctx_init(smp_processor_id());
+        if (xen_hvm_domain()) {
+                xen_callback_vector();
+                native_init_IRQ();
+        } else {
+                irq_ctx_init(smp_processor_id());
+        }
 }
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index f66db3b91d61..6c4531816496 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 unsigned int boot_max_nr_grant_frames;
 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 @@ static unsigned int __max_nr_grant_frames(void)
         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 @@ static inline unsigned int max_nr_grant_frames(void)
                 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 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
         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 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 
         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 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 
 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 @@ static int gnttab_expand(unsigned int req_entries)
         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 @@ static int gnttab_expand(unsigned int req_entries)
         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 @@ static int __devinit gnttab_init(void)
         kfree(gnttab_list);
         return -ENOMEM;
 }
+EXPORT_SYMBOL_GPL(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);
+core_initcall(__gnttab_init);
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 07e857b0de13..1799bd890315 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -9,6 +9,7 @@
 #include <linux/stop_machine.h>
 #include <linux/freezer.h>
 
+#include <xen/xen.h>
 #include <xen/xenbus.h>
 #include <xen/grant_table.h>
 #include <xen/events.h>
@@ -17,6 +18,7 @@
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/page.h>
+#include <asm/xen/hypervisor.h>
 
 enum shutdown_state {
         SHUTDOWN_INVALID = -1,
@@ -33,10 +35,30 @@ enum shutdown_state {
 static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
 
 #ifdef CONFIG_PM_SLEEP
-static int xen_suspend(void *data)
+static int xen_hvm_suspend(void *data)
 {
+        struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
         int *cancelled = data;
+
+        BUG_ON(!irqs_disabled());
+
+        *cancelled = HYPERVISOR_sched_op(SCHEDOP_shutdown, &r);
+
+        xen_hvm_post_suspend(*cancelled);
+        gnttab_resume();
+
+        if (!*cancelled) {
+                xen_irq_resume();
+                xen_timer_resume();
+        }
+
+        return 0;
+}
+
+static int xen_suspend(void *data)
+{
         int err;
+        int *cancelled = data;
 
         BUG_ON(!irqs_disabled());
 
@@ -106,7 +128,10 @@ static void do_suspend(void)
                 goto out_resume;
         }
 
-        err = stop_machine(xen_suspend, &cancelled, cpumask_of(0));
+        if (xen_hvm_domain())
+                err = stop_machine(xen_hvm_suspend, &cancelled, cpumask_of(0));
+        else
+                err = stop_machine(xen_suspend, &cancelled, cpumask_of(0));
 
         dpm_resume_noirq(PMSG_RESUME);
 
@@ -255,7 +280,19 @@ static int shutdown_event(struct notifier_block *notifier,
         return NOTIFY_DONE;
 }
 
-static int __init setup_shutdown_event(void)
+static int __init __setup_shutdown_event(void)
+{
+        /* Delay initialization in the PV on HVM case */
+        if (xen_hvm_domain())
+                return 0;
+
+        if (!xen_pv_domain())
+                return -ENODEV;
+
+        return xen_setup_shutdown_event();
+}
+
+int xen_setup_shutdown_event(void)
 {
         static struct notifier_block xenstore_notifier = {
                 .notifier_call = shutdown_event
@@ -264,5 +301,6 @@ static int __init setup_shutdown_event(void)
 
         return 0;
 }
+EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
 
-subsys_initcall(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 000000000000..c01b5ddce529
--- /dev/null
+++ b/drivers/xen/platform-pci.c
@@ -0,0 +1,207 @@
+/******************************************************************************
+ * 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/platform_pci.h>
+#include <xen/grant_table.h>
+#include <xen/xenbus.h>
+#include <xen/events.h>
+#include <xen/hvm.h>
+#include <xen/xen-ops.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;
+static uint64_t callback_via;
+
+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 platform_pci_resume(struct pci_dev *pdev)
+{
+        int err;
+        if (xen_have_vector_callback)
+                return 0;
+        err = xen_set_callback_via(callback_via);
+        if (err) {
+                dev_err(&pdev->dev, "platform_pci_resume failure!\n");
+                return err;
+        }
+        return 0;
+}
+
+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;
+        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);
+        ret = xen_setup_shutdown_event();
+        if (ret)
+                goto out;
+        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,
+#ifdef CONFIG_PM
+        .resume_early =   platform_pci_resume,
+#endif
+};
+
+static int __init platform_pci_module_init(void)
+{
+        /* no unplug has been done, IGNORE hasn't been specified: just
+         * return now */
+        if (!xen_platform_pci_unplug)
+                return -ENODEV;
+
+        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 3479332113e9..29bac5118877 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -56,6 +56,9 @@
 #include <xen/events.h>
 #include <xen/page.h>
 
+#include <xen/platform_pci.h>
+#include <xen/hvm.h>
+
 #include "xenbus_comms.h"
 #include "xenbus_probe.h"
 
@@ -752,10 +755,7 @@ int register_xenstore_notifier(struct notifier_block *nb)
 {
         int ret = 0;
 
-        if (xenstored_ready > 0)
-                ret = nb->notifier_call(nb, 0, NULL);
-        else
-                blocking_notifier_chain_register(&xenstore_chain, nb);
+        blocking_notifier_chain_register(&xenstore_chain, nb);
 
         return ret;
 }
@@ -779,8 +779,23 @@ void xenbus_probe(struct work_struct *unused)
         /* Notify others that xenstore is up */
         blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
 }
+EXPORT_SYMBOL_GPL(xenbus_probe);
+
+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_probe_init(void)
+static int __init xenbus_init(void)
 {
         int err = 0;
 
@@ -805,11 +820,24 @@ static int __init xenbus_probe_init(void)
         if (xen_initial_domain()) {
                 /* dom0 not yet supported */
         } else {
+                if (xen_hvm_domain()) {
+                        uint64_t v = 0;
+                        err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
+                        if (err)
+                                goto out_error;
+                        xen_store_evtchn = (int)v;
+                        err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
+                        if (err)
+                                goto out_error;
+                        xen_store_mfn = (unsigned long)v;
+                        xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
+                } else {
+                        xen_store_evtchn = xen_start_info->store_evtchn;
+                        xen_store_mfn = xen_start_info->store_mfn;
+                        xen_store_interface = mfn_to_virt(xen_store_mfn);
+                }
                 xenstored_ready = 1;
-                xen_store_evtchn = xen_start_info->store_evtchn;
-                xen_store_mfn = xen_start_info->store_mfn;
         }
-        xen_store_interface = mfn_to_virt(xen_store_mfn);
 
         /* Initialize the interface to xenstore. */
         err = xs_init();
@@ -819,9 +847,6 @@ static int __init xenbus_probe_init(void)
                 goto out_unreg_back;
         }
 
-        if (!xen_initial_domain())
-                xenbus_probe(NULL);
-
 #ifdef CONFIG_XEN_COMPAT_XENFS
         /*
          * Create xenfs mountpoint in /proc for compatibility with
@@ -842,7 +867,7 @@ static int __init xenbus_probe_init(void)
         return err;
 }
 
-postcore_initcall(xenbus_probe_init);
+postcore_initcall(xenbus_init);
 
 MODULE_LICENSE("GPL");
 
@@ -950,6 +975,9 @@ static void wait_for_devices(struct xenbus_driver *xendrv)
 #ifndef MODULE
 static int __init boot_wait_for_devices(void)
 {
+        if (xen_hvm_domain() && !xen_platform_pci_unplug)
+                return -ENODEV;
+
         ready_to_wait_for_devices = 1;
         wait_for_devices(NULL);
         return 0;
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 7b547f53f65e..5534690075af 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -76,6 +76,14 @@ struct xs_handle {
         /*
          * Mutex ordering: transaction_mutex -> watch_mutex -> request_mutex.
          * response_mutex is never taken simultaneously with the other three.
+         *
+         * transaction_mutex must be held before incrementing
+         * transaction_count. The mutex is held when a suspend is in
+         * progress to prevent new transactions starting.
+         *
+         * When decrementing transaction_count to zero the wait queue
+         * should be woken up, the suspend code waits for count to
+         * reach zero.
          */
 
         /* One request at a time. */
@@ -85,7 +93,9 @@ struct xs_handle {
         struct mutex response_mutex;
 
         /* Protect transactions against save/restore. */
-        struct rw_semaphore transaction_mutex;
+        struct mutex transaction_mutex;
+        atomic_t transaction_count;
+        wait_queue_head_t transaction_wq;
 
         /* Protect watch (de)register against save/restore. */
         struct rw_semaphore watch_mutex;
@@ -157,6 +167,31 @@ static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
         return body;
 }
 
+static void transaction_start(void)
+{
+        mutex_lock(&xs_state.transaction_mutex);
+        atomic_inc(&xs_state.transaction_count);
+        mutex_unlock(&xs_state.transaction_mutex);
+}
+
+static void transaction_end(void)
+{
+        if (atomic_dec_and_test(&xs_state.transaction_count))
+                wake_up(&xs_state.transaction_wq);
+}
+
+static void transaction_suspend(void)
+{
+        mutex_lock(&xs_state.transaction_mutex);
+        wait_event(xs_state.transaction_wq,
+                   atomic_read(&xs_state.transaction_count) == 0);
+}
+
+static void transaction_resume(void)
+{
+        mutex_unlock(&xs_state.transaction_mutex);
+}
+
 void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 {
         void *ret;
@@ -164,7 +199,7 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
         int err;
 
         if (req_msg.type == XS_TRANSACTION_START)
-                down_read(&xs_state.transaction_mutex);
+                transaction_start();
 
         mutex_lock(&xs_state.request_mutex);
 
@@ -180,7 +215,7 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
         if ((msg->type == XS_TRANSACTION_END) ||
             ((req_msg.type == XS_TRANSACTION_START) &&
              (msg->type == XS_ERROR)))
-                up_read(&xs_state.transaction_mutex);
+                transaction_end();
 
         return ret;
 }
@@ -432,11 +467,11 @@ int xenbus_transaction_start(struct xenbus_transaction *t)
 {
         char *id_str;
 
-        down_read(&xs_state.transaction_mutex);
+        transaction_start();
 
         id_str = xs_single(XBT_NIL, XS_TRANSACTION_START, "", NULL);
         if (IS_ERR(id_str)) {
-                up_read(&xs_state.transaction_mutex);
+                transaction_end();
                 return PTR_ERR(id_str);
         }
 
@@ -461,7 +496,7 @@ int xenbus_transaction_end(struct xenbus_transaction t, int abort)
 
         err = xs_error(xs_single(t, XS_TRANSACTION_END, abortstr, NULL));
 
-        up_read(&xs_state.transaction_mutex);
+        transaction_end();
 
         return err;
 }
@@ -662,7 +697,7 @@ EXPORT_SYMBOL_GPL(unregister_xenbus_watch);
 
 void xs_suspend(void)
 {
-        down_write(&xs_state.transaction_mutex);
+        transaction_suspend();
         down_write(&xs_state.watch_mutex);
         mutex_lock(&xs_state.request_mutex);
         mutex_lock(&xs_state.response_mutex);
@@ -677,7 +712,7 @@ void xs_resume(void)
 
         mutex_unlock(&xs_state.response_mutex);
         mutex_unlock(&xs_state.request_mutex);
-        up_write(&xs_state.transaction_mutex);
+        transaction_resume();
 
         /* No need for watches_lock: the watch_mutex is sufficient. */
         list_for_each_entry(watch, &watches, list) {
@@ -693,7 +728,7 @@ void xs_suspend_cancel(void)
         mutex_unlock(&xs_state.response_mutex);
         mutex_unlock(&xs_state.request_mutex);
         up_write(&xs_state.watch_mutex);
-        up_write(&xs_state.transaction_mutex);
+        mutex_unlock(&xs_state.transaction_mutex);
 }
 
 static int xenwatch_thread(void *unused)
@@ -843,8 +878,10 @@ int xs_init(void)
 
         mutex_init(&xs_state.request_mutex);
         mutex_init(&xs_state.response_mutex);
-        init_rwsem(&xs_state.transaction_mutex);
+        mutex_init(&xs_state.transaction_mutex);
         init_rwsem(&xs_state.watch_mutex);
+        atomic_set(&xs_state.transaction_count, 0);
+        init_waitqueue_head(&xs_state.transaction_wq);
 
         /* Initialize the shared memory rings to talk to xenstored */
         err = xb_init_comms();
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index 8924d93136f1..78bfab0700ba 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -65,7 +65,7 @@ static struct file_system_type xenfs_type = {
 
 static int __init xenfs_init(void)
 {
-        if (xen_pv_domain())
+        if (xen_domain())
                 return register_filesystem(&xenfs_type);
 
         printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n");
@@ -74,7 +74,7 @@ static int __init xenfs_init(void)
 
 static void __exit xenfs_exit(void)
 {
-        if (xen_pv_domain())
+        if (xen_domain())
                 unregister_filesystem(&xenfs_type);
 }
 
diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c
index f28ece397361..3b39c3752e21 100644
--- a/drivers/xen/xenfs/xenbus.c
+++ b/drivers/xen/xenfs/xenbus.c
@@ -124,6 +124,9 @@ static ssize_t xenbus_file_read(struct file *filp,
         mutex_lock(&u->reply_mutex);
         while (list_empty(&u->read_buffers)) {
                 mutex_unlock(&u->reply_mutex);
+                if (filp->f_flags & O_NONBLOCK)
+                        return -EAGAIN;
+
                 ret = wait_event_interruptible(u->read_waitq,
                                                !list_empty(&u->read_buffers));
                 if (ret)