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[PATCH 2/2] RFC: Xen pad logic

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>From ba9abf6ee7e5fe0515e2d51b14743c8d5416285c Mon Sep 17 00:00:00 2001
From: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
Date: Fri, 24 Feb 2012 02:18:02 +0800
Subject: [PATCH 2/2] Xen pad logic

This patch implement Xen pad logic, and when getting pad device
notification, it hypercalls to Xen hypervisor for core parking.

Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
---
 arch/x86/xen/enlighten.c         |    2 +
 arch/x86/xen/xen-ops.h           |    1 +
 drivers/xen/Makefile             |    1 +
 drivers/xen/xen_acpi_pad.c       |  190 ++++++++++++++++++++++++++++++++++++++
 include/xen/interface/platform.h |   14 +++
 5 files changed, 208 insertions(+), 0 deletions(-)
 create mode 100644 drivers/xen/xen_acpi_pad.c

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 12eb07b..3cce71f 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1133,6 +1133,8 @@ asmlinkage void __init xen_start_kernel(void)
 
 	xen_init_time_ops();
 
+	xen_init_pad_ops();
+
 	/*
 	 * Set up some pagetable state before starting to set any ptes.
 	 */
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index b095739..7eee651 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -54,6 +54,7 @@ void xen_teardown_timer(int cpu);
 cycle_t xen_clocksource_read(void);
 void xen_setup_cpu_clockevents(void);
 void __init xen_init_time_ops(void);
+void __init xen_init_pad_ops(void);
 void __init xen_hvm_init_time_ops(void);
 
 irqreturn_t xen_debug_interrupt(int irq, void *dev_id);
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index aa31337..c0268c9 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_SWIOTLB_XEN)		+= swiotlb-xen.o
 obj-$(CONFIG_XEN_DOM0)			+= pci.o
 obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
 obj-$(CONFIG_XEN_PRIVCMD)		+= xen-privcmd.o
+obj-$(CONFIG_XEN_DOM0)			+= xen_acpi_pad.o
 
 xen-evtchn-y				:= evtchn.o
 xen-gntdev-y				:= gntdev.o
diff --git a/drivers/xen/xen_acpi_pad.c b/drivers/xen/xen_acpi_pad.c
new file mode 100644
index 0000000..4a1f2f7
--- /dev/null
+++ b/drivers/xen/xen_acpi_pad.c
@@ -0,0 +1,190 @@
+/*
+ * xen_acpi_pad.c - Xen pad interface
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ *    Author: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
+ *
+ * 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>
+
+static DEFINE_MUTEX(xen_cpu_lock);
+
+static int xen_acpi_pad_idle_cpus(int *num_cpus)
+{
+	int ret;
+
+	struct xen_platform_op op = {
+		.cmd = XENPF_core_parking,
+		.interface_version = XENPF_INTERFACE_VERSION,
+	};
+
+	/* set cpu nums expected to be idled */
+	op.u.core_parking.type = XEN_CORE_PARKING_SET;
+	op.u.core_parking.idle_nums = (uint32_t)*num_cpus;
+	ret = HYPERVISOR_dom0_op(&op);
+	if (ret)
+		return ret;
+
+	/*
+	 * get cpu nums actually be idled
+	 * cannot get it by using hypercall once (shared with _SET)
+	 * because of the characteristic of Xen continue_hypercall_on_cpu
+	 */
+	op.u.core_parking.type = XEN_CORE_PARKING_GET;
+	ret = HYPERVISOR_dom0_op(&op);
+	if (ret)
+		return ret;
+
+	*num_cpus = op.u.core_parking.idle_nums;
+	return 0;
+}
+
+/*
+ * Query firmware how many CPUs should be idle
+ * return -1 on failure
+ */
+static int xen_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 xen_acpi_pad_ost(acpi_handle handle, int stat,
+	uint32_t idle_cpus)
+{
+	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_cpus;
+	acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
+}
+
+static void xen_acpi_pad_handle_notify(acpi_handle handle)
+{
+	int ret, num_cpus;
+
+	mutex_lock(&xen_cpu_lock);
+	num_cpus = xen_acpi_pad_pur(handle);
+	if (num_cpus < 0) {
+		mutex_unlock(&xen_cpu_lock);
+		return;
+	}
+
+	ret = xen_acpi_pad_idle_cpus(&num_cpus);
+	if (ret) {
+		mutex_unlock(&xen_cpu_lock);
+		return;
+	}
+
+	xen_acpi_pad_ost(handle, 0, num_cpus);
+	mutex_unlock(&xen_cpu_lock);
+}
+
+static void xen_acpi_pad_notify(acpi_handle handle, u32 event,
+	void *data)
+{
+	switch (event) {
+	case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
+		xen_acpi_pad_handle_notify(handle);
+		break;
+	default:
+		printk(KERN_WARNING "Unsupported event [0x%x]\n", event);
+		break;
+	}
+}
+
+static int xen_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, xen_acpi_pad_notify, device);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return 0;
+}
+
+static int xen_acpi_pad_remove(struct acpi_device *device,
+	int type)
+{
+	int num_cpus = 0;
+
+	mutex_lock(&xen_cpu_lock);
+	xen_acpi_pad_idle_cpus(&num_cpus);
+	mutex_unlock(&xen_cpu_lock);
+
+	acpi_remove_notify_handler(device->handle,
+		ACPI_DEVICE_NOTIFY, xen_acpi_pad_notify);
+	return 0;
+}
+
+static const struct acpi_device_id xen_pad_device_ids[] = {
+	{"ACPI000C", 0},
+	{"", 0},
+};
+
+static struct acpi_driver xen_acpi_pad_driver = {
+	.name = "processor_aggregator",
+	.class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
+	.ids = xen_pad_device_ids,
+	.ops = {
+		.add = xen_acpi_pad_add,
+		.remove = xen_acpi_pad_remove,
+	},
+};
+
+static int __init xen_acpi_pad_init(void)
+{
+	return acpi_bus_register_driver(&xen_acpi_pad_driver);
+}
+
+void __init xen_init_pad_ops(void)
+{
+#ifdef CONFIG_ACPI_PROCESSOR_AGGREGATOR
+	acpi_pad_ops.init = xen_acpi_pad_init;
+#endif
+}
diff --git a/include/xen/interface/platform.h b/include/xen/interface/platform.h
index c168468..56ec72a 100644
--- a/include/xen/interface/platform.h
+++ b/include/xen/interface/platform.h
@@ -297,6 +297,19 @@ struct xenpf_set_processor_pminfo {
 };
 DEFINE_GUEST_HANDLE_STRUCT(xenpf_set_processor_pminfo);
 
+#define XENPF_core_parking      60
+
+#define XEN_CORE_PARKING_SET    1
+#define XEN_CORE_PARKING_GET    2
+struct xenpf_core_parking {
+	/* IN variables */
+	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 */
@@ -312,6 +325,7 @@ struct xen_platform_op {
 		struct xenpf_change_freq       change_freq;
 		struct xenpf_getidletime       getidletime;
 		struct xenpf_set_processor_pminfo set_pminfo;
+		struct xenpf_core_parking      core_parking;
 		uint8_t                        pad[128];
 	} u;
 };
-- 
1.7.1

Attachment: 0002-Xen-pad-logic.patch
Description: 0002-Xen-pad-logic.patch


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