4 files changed, 519 insertions, 0 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index dcffad1b47ca..5a32232cf7c1 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -202,6 +202,18 @@ config XEN_ACPI_HOTPLUG_MEMORY
           to hot-add memory at runtime (the hot-added memory cannot be
           removed until machine stop), select Y/M here, otherwise select N.
 
+config XEN_ACPI_HOTPLUG_CPU
+        tristate "Xen ACPI cpu hotplug"
+        depends on XEN_DOM0 && XEN_STUB && ACPI
+        select ACPI_CONTAINER
+        default n
+        help
+          Xen ACPI cpu enumerating and hotplugging
+
+          For hotplugging, currently Xen only support ACPI cpu hotadd.
+          If you want to hotadd cpu at runtime (the hotadded cpu cannot
+          be removed until machine stop), select Y/M here.
+
 config XEN_ACPI_PROCESSOR
         tristate "Xen ACPI processor"
         depends on XEN && X86 && ACPI_PROCESSOR && CPU_FREQ
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 1605f594ff56..eabd0ee1c2bc 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
 obj-$(CONFIG_XEN_PRIVCMD)               += xen-privcmd.o
 obj-$(CONFIG_XEN_STUB)                  += xen-stub.o
 obj-$(CONFIG_XEN_ACPI_HOTPLUG_MEMORY)   += xen-acpi-memhotplug.o
+obj-$(CONFIG_XEN_ACPI_HOTPLUG_CPU)      += xen-acpi-cpuhotplug.o
 obj-$(CONFIG_XEN_ACPI_PROCESSOR)        += xen-acpi-processor.o
 xen-evtchn-y                            := evtchn.o
 xen-gntdev-y                            := gntdev.o
diff --git a/drivers/xen/pcpu.c b/drivers/xen/pcpu.c
index 067fcfa1723e..0836a18675b1 100644
--- a/drivers/xen/pcpu.c
+++ b/drivers/xen/pcpu.c
@@ -333,6 +333,41 @@ static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id)
         return IRQ_HANDLED;
 }
 
+/* Sync with Xen hypervisor after cpu hotadded */
+void xen_pcpu_hotplug_sync(void)
+{
+        schedule_work(&xen_pcpu_work);
+}
+EXPORT_SYMBOL_GPL(xen_pcpu_hotplug_sync);
+
+/*
+ * For hypervisor presented cpu, return logic cpu id;
+ * For hypervisor non-presented cpu, return -ENODEV.
+ */
+int xen_pcpu_id(uint32_t acpi_id)
+{
+        int cpu_id = 0, max_id = 0;
+        struct xen_platform_op op;
+
+        op.cmd = XENPF_get_cpuinfo;
+        while (cpu_id <= max_id) {
+                op.u.pcpu_info.xen_cpuid = cpu_id;
+                if (HYPERVISOR_dom0_op(&op)) {
+                        cpu_id++;
+                        continue;
+                }
+
+                if (acpi_id == op.u.pcpu_info.acpi_id)
+                        return cpu_id;
+                if (op.u.pcpu_info.max_present > max_id)
+                        max_id = op.u.pcpu_info.max_present;
+                cpu_id++;
+        }
+
+        return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(xen_pcpu_id);
+
 static int __init xen_pcpu_init(void)
 {
         int irq, ret;
diff --git a/drivers/xen/xen-acpi-cpuhotplug.c b/drivers/xen/xen-acpi-cpuhotplug.c
new file mode 100644
index 000000000000..9eefbb0f79a3
--- /dev/null
+++ b/drivers/xen/xen-acpi-cpuhotplug.c
@@ -0,0 +1,471 @@
+/*
+ * Copyright (C) 2012 Intel Corporation
+ *    Author: Liu Jinsong <jinsong.liu@intel.com>
+ *    Author: Jiang Yunhong <yunhong.jiang@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/cpu.h>
+#include <linux/acpi.h>
+#include <linux/uaccess.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+#include <acpi/processor.h>
+
+#include <xen/acpi.h>
+#include <xen/interface/platform.h>
+#include <asm/xen/hypercall.h>
+
+#define PREFIX "ACPI:xen_cpu_hotplug:"
+
+#define INSTALL_NOTIFY_HANDLER          0
+#define UNINSTALL_NOTIFY_HANDLER        1
+
+static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
+
+/* --------------------------------------------------------------------------
+                                Driver Interface
+-------------------------------------------------------------------------- */
+
+static int xen_acpi_processor_enable(struct acpi_device *device)
+{
+        acpi_status status = 0;
+        unsigned long long value;
+        union acpi_object object = { 0 };
+        struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
+        struct acpi_processor *pr;
+
+        pr = acpi_driver_data(device);
+        if (!pr) {
+                pr_err(PREFIX "Cannot find driver data\n");
+                return -EINVAL;
+        }
+
+        if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
+                /* Declared with "Processor" statement; match ProcessorID */
+                status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
+                if (ACPI_FAILURE(status)) {
+                        pr_err(PREFIX "Evaluating processor object\n");
+                        return -ENODEV;
+                }
+
+                pr->acpi_id = object.processor.proc_id;
+        } else {
+                /* Declared with "Device" statement; match _UID */
+                status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
+                                                NULL, &value);
+                if (ACPI_FAILURE(status)) {
+                        pr_err(PREFIX "Evaluating processor _UID\n");
+                        return -ENODEV;
+                }
+
+                pr->acpi_id = value;
+        }
+
+        pr->id = xen_pcpu_id(pr->acpi_id);
+
+        if ((int)pr->id < 0)
+                /* This cpu is not presented at hypervisor, try to hotadd it */
+                if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
+                        pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
+                                        pr->acpi_id);
+                        return -ENODEV;
+                }
+
+        return 0;
+}
+
+static int __cpuinit xen_acpi_processor_add(struct acpi_device *device)
+{
+        int ret;
+        struct acpi_processor *pr;
+
+        if (!device)
+                return -EINVAL;
+
+        pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
+        if (!pr)
+                return -ENOMEM;
+
+        pr->handle = device->handle;
+        strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
+        strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
+        device->driver_data = pr;
+
+        ret = xen_acpi_processor_enable(device);
+        if (ret)
+                pr_err(PREFIX "Error when enabling Xen processor\n");
+
+        return ret;
+}
+
+static int xen_acpi_processor_remove(struct acpi_device *device, int type)
+{
+        struct acpi_processor *pr;
+
+        if (!device)
+                return -EINVAL;
+
+        pr = acpi_driver_data(device);
+        if (!pr)
+                return -EINVAL;
+
+        kfree(pr);
+        return 0;
+}
+
+/*--------------------------------------------------------------
+                Acpi processor hotplug support
+--------------------------------------------------------------*/
+
+static int is_processor_present(acpi_handle handle)
+{
+        acpi_status status;
+        unsigned long long sta = 0;
+
+
+        status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
+
+        if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
+                return 1;
+
+        /*
+         * _STA is mandatory for a processor that supports hot plug
+         */
+        if (status == AE_NOT_FOUND)
+                pr_info(PREFIX "Processor does not support hot plug\n");
+        else
+                pr_info(PREFIX "Processor Device is not present");
+        return 0;
+}
+
+static int xen_apic_id(acpi_handle handle)
+{
+        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+        union acpi_object *obj;
+        struct acpi_madt_local_apic *lapic;
+        int apic_id;
+
+        if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
+                return -EINVAL;
+
+        if (!buffer.length || !buffer.pointer)
+                return -EINVAL;
+
+        obj = buffer.pointer;
+        if (obj->type != ACPI_TYPE_BUFFER ||
+            obj->buffer.length < sizeof(*lapic)) {
+                kfree(buffer.pointer);
+                return -EINVAL;
+        }
+
+        lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
+
+        if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
+            !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
+                kfree(buffer.pointer);
+                return -EINVAL;
+        }
+
+        apic_id = (uint32_t)lapic->id;
+        kfree(buffer.pointer);
+        buffer.length = ACPI_ALLOCATE_BUFFER;
+        buffer.pointer = NULL;
+
+        return apic_id;
+}
+
+static int xen_hotadd_cpu(struct acpi_processor *pr)
+{
+        int cpu_id, apic_id, pxm;
+        struct xen_platform_op op;
+
+        apic_id = xen_apic_id(pr->handle);
+        if (apic_id < 0) {
+                pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
+                                pr->acpi_id);
+                return -ENODEV;
+        }
+
+        pxm = xen_acpi_get_pxm(pr->handle);
+        if (pxm < 0) {
+                pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
+                                pr->acpi_id);
+                return pxm;
+        }
+
+        op.cmd = XENPF_cpu_hotadd;
+        op.u.cpu_add.apic_id = apic_id;
+        op.u.cpu_add.acpi_id = pr->acpi_id;
+        op.u.cpu_add.pxm = pxm;
+
+        cpu_id = HYPERVISOR_dom0_op(&op);
+        if (cpu_id < 0)
+                pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
+                                pr->acpi_id);
+
+        return cpu_id;
+}
+
+static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
+{
+        if (!is_processor_present(pr->handle))
+                return AE_ERROR;
+
+        pr->id = xen_hotadd_cpu(pr);
+        if ((int)pr->id < 0)
+                return AE_ERROR;
+
+        /*
+         * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
+         * interface after cpu hotadded.
+         */
+        xen_pcpu_hotplug_sync();
+
+        return AE_OK;
+}
+
+static
+int acpi_processor_device_add(acpi_handle handle, struct acpi_device **device)
+{
+        acpi_handle phandle;
+        struct acpi_device *pdev;
+
+        if (acpi_get_parent(handle, &phandle))
+                return -ENODEV;
+
+        if (acpi_bus_get_device(phandle, &pdev))
+                return -ENODEV;
+
+        if (acpi_bus_add(device, pdev, handle, ACPI_BUS_TYPE_PROCESSOR))
+                return -ENODEV;
+
+        return 0;
+}
+
+static int acpi_processor_device_remove(struct acpi_device *device)
+{
+        pr_debug(PREFIX "Xen does not support CPU hotremove\n");
+
+        return -ENOSYS;
+}
+
+static void acpi_processor_hotplug_notify(acpi_handle handle,
+                                          u32 event, void *data)
+{
+        struct acpi_processor *pr;
+        struct acpi_device *device = NULL;
+        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
+        int result;
+
+        switch (event) {
+        case ACPI_NOTIFY_BUS_CHECK:
+        case ACPI_NOTIFY_DEVICE_CHECK:
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                        "Processor driver received %s event\n",
+                        (event == ACPI_NOTIFY_BUS_CHECK) ?
+                        "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
+
+                if (!is_processor_present(handle))
+                        break;
+
+                if (!acpi_bus_get_device(handle, &device))
+                        break;
+
+                result = acpi_processor_device_add(handle, &device);
+                if (result) {
+                        pr_err(PREFIX "Unable to add the device\n");
+                        break;
+                }
+
+                ost_code = ACPI_OST_SC_SUCCESS;
+                break;
+
+        case ACPI_NOTIFY_EJECT_REQUEST:
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                  "received ACPI_NOTIFY_EJECT_REQUEST\n"));
+
+                if (acpi_bus_get_device(handle, &device)) {
+                        pr_err(PREFIX "Device don't exist, dropping EJECT\n");
+                        break;
+                }
+                pr = acpi_driver_data(device);
+                if (!pr) {
+                        pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
+                        break;
+                }
+
+                /*
+                 * TBD: implement acpi_processor_device_remove if Xen support
+                 * CPU hotremove in the future.
+                 */
+                acpi_processor_device_remove(device);
+                break;
+
+        default:
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                  "Unsupported event [0x%x]\n", event));
+
+                /* non-hotplug event; possibly handled by other handler */
+                return;
+        }
+
+        (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
+        return;
+}
+
+static acpi_status is_processor_device(acpi_handle handle)
+{
+        struct acpi_device_info *info;
+        char *hid;
+        acpi_status status;
+
+        status = acpi_get_object_info(handle, &info);
+        if (ACPI_FAILURE(status))
+                return status;
+
+        if (info->type == ACPI_TYPE_PROCESSOR) {
+                kfree(info);
+                return AE_OK;   /* found a processor object */
+        }
+
+        if (!(info->valid & ACPI_VALID_HID)) {
+                kfree(info);
+                return AE_ERROR;
+        }
+
+        hid = info->hardware_id.string;
+        if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
+                kfree(info);
+                return AE_ERROR;
+        }
+
+        kfree(info);
+        return AE_OK;   /* found a processor device object */
+}
+
+static acpi_status
+processor_walk_namespace_cb(acpi_handle handle,
+                            u32 lvl, void *context, void **rv)
+{
+        acpi_status status;
+        int *action = context;
+
+        status = is_processor_device(handle);
+        if (ACPI_FAILURE(status))
+                return AE_OK;   /* not a processor; continue to walk */
+
+        switch (*action) {
+        case INSTALL_NOTIFY_HANDLER:
+                acpi_install_notify_handler(handle,
+                                            ACPI_SYSTEM_NOTIFY,
+                                            acpi_processor_hotplug_notify,
+                                            NULL);
+                break;
+        case UNINSTALL_NOTIFY_HANDLER:
+                acpi_remove_notify_handler(handle,
+                                           ACPI_SYSTEM_NOTIFY,
+                                           acpi_processor_hotplug_notify);
+                break;
+        default:
+                break;
+        }
+
+        /* found a processor; skip walking underneath */
+        return AE_CTRL_DEPTH;
+}
+
+static
+void acpi_processor_install_hotplug_notify(void)
+{
+        int action = INSTALL_NOTIFY_HANDLER;
+        acpi_walk_namespace(ACPI_TYPE_ANY,
+                            ACPI_ROOT_OBJECT,
+                            ACPI_UINT32_MAX,
+                            processor_walk_namespace_cb, NULL, &action, NULL);
+}
+
+static
+void acpi_processor_uninstall_hotplug_notify(void)
+{
+        int action = UNINSTALL_NOTIFY_HANDLER;
+        acpi_walk_namespace(ACPI_TYPE_ANY,
+                            ACPI_ROOT_OBJECT,
+                            ACPI_UINT32_MAX,
+                            processor_walk_namespace_cb, NULL, &action, NULL);
+}
+
+static const struct acpi_device_id processor_device_ids[] = {
+        {ACPI_PROCESSOR_OBJECT_HID, 0},
+        {ACPI_PROCESSOR_DEVICE_HID, 0},
+        {"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, processor_device_ids);
+
+static struct acpi_driver xen_acpi_processor_driver = {
+        .name = "processor",
+        .class = ACPI_PROCESSOR_CLASS,
+        .ids = processor_device_ids,
+        .ops = {
+                .add = xen_acpi_processor_add,
+                .remove = xen_acpi_processor_remove,
+                },
+};
+
+static int __init xen_acpi_processor_init(void)
+{
+        int result = 0;
+
+        if (!xen_initial_domain())
+                return -ENODEV;
+
+        /* unregister the stub which only used to reserve driver space */
+        xen_stub_processor_exit();
+
+        result = acpi_bus_register_driver(&xen_acpi_processor_driver);
+        if (result < 0) {
+                xen_stub_processor_init();
+                return result;
+        }
+
+        acpi_processor_install_hotplug_notify();
+        return 0;
+}
+
+static void __exit xen_acpi_processor_exit(void)
+{
+        if (!xen_initial_domain())
+                return;
+
+        acpi_processor_uninstall_hotplug_notify();
+
+        acpi_bus_unregister_driver(&xen_acpi_processor_driver);
+
+        /*
+         * stub reserve space again to prevent any chance of native
+         * driver loading.
+         */
+        xen_stub_processor_init();
+        return;
+}
+
+module_init(xen_acpi_processor_init);
+module_exit(xen_acpi_processor_exit);
+ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
+MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
+MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
+MODULE_LICENSE("GPL");