Commit 39adc483 authored by Liu Jinsong's avatar Liu Jinsong Committed by Konrad Rzeszutek Wilk
Browse files

xen/acpi: ACPI cpu hotplug 



This patch implement real Xen ACPI cpu hotplug driver as module.
When loaded, it replaces Xen stub driver.

For booting existed cpus, the driver enumerates them.
For hotadded cpus, which added at runtime and notify OS via
device or container event, the driver is invoked to add them,
parsing cpu information, hypercalling to Xen hypervisor to add
them, and finally setting up new /sys interface for them.

Signed-off-by: default avatarLiu Jinsong <jinsong.liu@intel.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 40a58637

drivers/xen/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -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

drivers/xen/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/xen/pcpu.c

+35 −0
Original line number Diff line number Diff line
@@ -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;

drivers/xen/xen-acpi-cpuhotplug.c

0 → 100644
+471 −0
Original line number Diff line number Diff line 
/*

 * 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");

include/xen/acpi.h

+3 −0
Original line number Diff line number Diff line
@@ -54,6 +54,9 @@ void xen_stub_memory_device_exit(void); 
int xen_stub_processor_init(void);

void xen_stub_processor_exit(void);



void xen_pcpu_hotplug_sync(void);

int xen_pcpu_id(uint32_t acpi_id);



int xen_acpi_notify_hypervisor_state(u8 sleep_state,

				     u32 pm1a_cnt, u32 pm1b_cnd);

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