diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 0e86370354572ac7d4116eb70cf6e41d1a52cf35..3c397170f39c7dcd2ce393f6e5f6678f3c5bf532 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -10,7 +10,8 @@ CFLAGS_features.o := $(nostackp)
dom0-$(CONFIG_PCI) += pci.o
dom0-$(CONFIG_USB_SUPPORT) += dbgp.o
-dom0-$(CONFIG_ACPI) += acpi.o
+dom0-$(CONFIG_ACPI) += acpi.o $(xen-pad-y)
+xen-pad-$(CONFIG_X86) += xen-acpi-pad.o
dom0-$(CONFIG_X86) += pcpu.o
obj-$(CONFIG_XEN_DOM0) += $(dom0-y)
obj-$(CONFIG_BLOCK) += biomerge.o
diff --git a/drivers/xen/xen-acpi-pad.c b/drivers/xen/xen-acpi-pad.c
new file mode 100644
index 0000000000000000000000000000000000000000..f23ecf38008828f415160b30d9aa7a9ea8955b5b
--- /dev/null
+++ b/drivers/xen/xen-acpi-pad.c
@@ -0,0 +1,181 @@
+/*
+ * xen-acpi-pad.c - Xen pad interface
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ * Author: Liu, Jinsong <jinsong.liu@intel.com>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+#include <asm/xen/hypercall.h>
+#include <xen/interface/version.h>
+
+#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
+#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
+#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
+static DEFINE_MUTEX(xen_cpu_lock);
+
+static int xen_acpi_pad_idle_cpus(unsigned int idle_nums)
+{
+ struct xen_platform_op op;
+
+ op.cmd = XENPF_core_parking;
+ op.u.core_parking.type = XEN_CORE_PARKING_SET;
+ op.u.core_parking.idle_nums = idle_nums;
+
+ return HYPERVISOR_dom0_op(&op);
+}
+
+static int xen_acpi_pad_idle_cpus_num(void)
+{
+ struct xen_platform_op op;
+
+ op.cmd = XENPF_core_parking;
+ op.u.core_parking.type = XEN_CORE_PARKING_GET;
+
+ return HYPERVISOR_dom0_op(&op)
+ ?: op.u.core_parking.idle_nums;
+}
+
+/*
+ * Query firmware how many CPUs should be idle
+ * return -1 on failure
+ */
+static int acpi_pad_pur(acpi_handle handle)
+{
+ struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
+ union acpi_object *package;
+ int num = -1;
+
+ if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
+ return num;
+
+ if (!buffer.length || !buffer.pointer)
+ return num;
+
+ package = buffer.pointer;
+
+ if (package->type == ACPI_TYPE_PACKAGE &&
+ package->package.count == 2 &&
+ package->package.elements[0].integer.value == 1) /* rev 1 */
+ num = package->package.elements[1].integer.value;
+
+ kfree(buffer.pointer);
+ return num;
+}
+
+/* Notify firmware how many CPUs are idle */
+static void acpi_pad_ost(acpi_handle handle, int stat,
+ uint32_t idle_nums)
+{
+ union acpi_object params[3] = {
+ {.type = ACPI_TYPE_INTEGER,},
+ {.type = ACPI_TYPE_INTEGER,},
+ {.type = ACPI_TYPE_BUFFER,},
+ };
+ struct acpi_object_list arg_list = {3, params};
+
+ params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
+ params[1].integer.value = stat;
+ params[2].buffer.length = 4;
+ params[2].buffer.pointer = (void *)&idle_nums;
+ acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
+}
+
+static void acpi_pad_handle_notify(acpi_handle handle)
+{
+ int idle_nums;
+
+ mutex_lock(&xen_cpu_lock);
+ idle_nums = acpi_pad_pur(handle);
+ if (idle_nums < 0) {
+ mutex_unlock(&xen_cpu_lock);
+ return;
+ }
+
+ idle_nums = xen_acpi_pad_idle_cpus(idle_nums)
+ ?: xen_acpi_pad_idle_cpus_num();
+ if (idle_nums >= 0)
+ acpi_pad_ost(handle, 0, idle_nums);
+ mutex_unlock(&xen_cpu_lock);
+}
+
+static void acpi_pad_notify(acpi_handle handle, u32 event,
+ void *data)
+{
+ switch (event) {
+ case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
+ acpi_pad_handle_notify(handle);
+ break;
+ default:
+ pr_warn("Unsupported event [0x%x]\n", event);
+ break;
+ }
+}
+
+static int acpi_pad_add(struct acpi_device *device)
+{
+ acpi_status status;
+
+ strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
+ strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
+
+ status = acpi_install_notify_handler(device->handle,
+ ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ return 0;
+}
+
+static int acpi_pad_remove(struct acpi_device *device,
+ int type)
+{
+ mutex_lock(&xen_cpu_lock);
+ xen_acpi_pad_idle_cpus(0);
+ mutex_unlock(&xen_cpu_lock);
+
+ acpi_remove_notify_handler(device->handle,
+ ACPI_DEVICE_NOTIFY, acpi_pad_notify);
+ return 0;
+}
+
+static const struct acpi_device_id pad_device_ids[] = {
+ {"ACPI000C", 0},
+ {"", 0},
+};
+
+static struct acpi_driver acpi_pad_driver = {
+ .name = "processor_aggregator",
+ .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
+ .ids = pad_device_ids,
+ .ops = {
+ .add = acpi_pad_add,
+ .remove = acpi_pad_remove,
+ },
+};
+
+static int __init xen_acpi_pad_init(void)
+{
+ /* Only DOM0 is responsible for Xen acpi pad */
+ if (!xen_initial_domain())
+ return -ENODEV;
+
+ /* Only Xen4.2 or later support Xen acpi pad */
+ if (!xen_running_on_version_or_later(4, 2))
+ return -ENODEV;
+
+ return acpi_bus_register_driver(&acpi_pad_driver);
+}
+subsys_initcall(xen_acpi_pad_init);
diff --git a/include/xen/interface/platform.h b/include/xen/interface/platform.h
index 4755b5fac9c736b5fc010ae5d9a3e8c70838a232..5e36932ab40754181191c9966cfb735fdb58dbc1 100644
--- a/include/xen/interface/platform.h
+++ b/include/xen/interface/platform.h
@@ -324,6 +324,22 @@ struct xenpf_cpu_ol {
};
DEFINE_GUEST_HANDLE_STRUCT(xenpf_cpu_ol);
+/*
+ * CMD 58 and 59 are reserved for cpu hotadd and memory hotadd,
+ * which are already occupied at Xen hypervisor side.
+ */
+#define XENPF_core_parking 60
+struct xenpf_core_parking {
+ /* IN variables */
+#define XEN_CORE_PARKING_SET 1
+#define XEN_CORE_PARKING_GET 2
+ uint32_t type;
+ /* IN variables: set cpu nums expected to be idled */
+ /* OUT variables: get cpu nums actually be idled */
+ uint32_t idle_nums;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xenpf_core_parking);
+
struct xen_platform_op {
uint32_t cmd;
uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
@@ -341,6 +357,7 @@ struct xen_platform_op {
struct xenpf_set_processor_pminfo set_pminfo;
struct xenpf_pcpuinfo pcpu_info;
struct xenpf_cpu_ol cpu_ol;
+ struct xenpf_core_parking core_parking;
uint8_t pad[128];
} u;
};
diff --git a/include/xen/interface/version.h b/include/xen/interface/version.h
index 7ff6498679a371e218137b3b5d2e6f1691304795..96d8d3deea6b0d6c591657faf8fbc8c46bcc9ed9 100644
--- a/include/xen/interface/version.h
+++ b/include/xen/interface/version.h
@@ -63,4 +63,19 @@ struct xen_feature_info {
/* arg == xen_domain_handle_t. */
#define XENVER_guest_handle 8
+/* Check if running on Xen version (major, minor) or later */
+static inline bool
+xen_running_on_version_or_later(unsigned int major, unsigned int minor)
+{
+ unsigned int version;
+
+ if (!xen_domain())
+ return false;
+
+ version = HYPERVISOR_xen_version(XENVER_version, NULL);
+ if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
+ ((version >> 16) > major))
+ return true;
+ return false;
+}
#endif /* __XEN_PUBLIC_VERSION_H__ */