Message-ID: <DE8DF0795D48FD4CA783C40EC829233537292E@SHSMSX101.ccr.corp.intel.com>
Date:	Fri, 26 Oct 2012 14:00:36 +0000
From:	"Liu, Jinsong" <jinsong.liu@...el.com>
To:	"konrad.wilk@...cle.com" <konrad.wilk@...cle.com>,
	Jan Beulich <jbeulich@...e.com>
CC:	"xen-devel@...ts.xen.org" <xen-devel@...ts.xen.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Konrad Rzeszutek Wilk <konrad@...nel.org>
Subject: RE: [Xen-devel] [PATCH 1/2] Xen acpi pad implement

Updated per Jan's comments.

Thanks,
Jinsong

===============

>From e6d4eceba9538c6873f9c970425e65e257fd9bf0 Mon Sep 17 00:00:00 2001
From: Liu, Jinsong <jinsong.liu@...el.com>
Date: Sat, 27 Oct 2012 05:34:50 +0800
Subject: [PATCH 1/2] Xen acpi pad implement

PAD is acpi Processor Aggregator Device which provides a control point
that enables the platform to perform specific processor configuration
and control that applies to all processors in the platform.

This patch is to implement Xen acpi pad logic. When running under Xen
virt platform, native pad driver would not work. Instead Xen pad driver,
a self-contained and very thin logic level, would take over acpi pad staff.
When acpi pad notify OSPM, xen pad logic intercept and parse _PUR object
and then hypercall to hyervisor for the rest work, say, core parking.

Signed-off-by: Liu, Jinsong <jinsong.liu@...el.com>
---
 drivers/xen/Makefile             |    1 +
 drivers/xen/xen_acpi_pad.c       |  201 ++++++++++++++++++++++++++++++++++++++
 include/xen/interface/platform.h |   17 +++
 3 files changed, 219 insertions(+), 0 deletions(-)
 create mode 100644 drivers/xen/xen_acpi_pad.c

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 0e86370..a2af622 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_XEN_MCE_LOG)		+= mcelog.o
 obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
 obj-$(CONFIG_XEN_PRIVCMD)		+= xen-privcmd.o
 obj-$(CONFIG_XEN_ACPI_PROCESSOR)	+= xen-acpi-processor.o
+obj-$(CONFIG_XEN_DOM0)			+= xen_acpi_pad.o
 xen-evtchn-y				:= evtchn.o
 xen-gntdev-y				:= gntdev.o
 xen-gntalloc-y				:= gntalloc.o
diff --git a/drivers/xen/xen_acpi_pad.c b/drivers/xen/xen_acpi_pad.c
new file mode 100644
index 0000000..0f1a1e6
--- /dev/null
+++ b/drivers/xen/xen_acpi_pad.c
@@ -0,0 +1,201 @@
+/*
+ * xen_acpi_pad.c - Xen pad interface
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ *    Author: Liu, Jinsong <jinsong.liu@...el.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>
+
+#if defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR) || \
+		defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR_MODULE)
+
+#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_pad_lock);
+
+static int xen_pad_set_idle_cpus(int num_cpus)
+{
+	struct xen_platform_op op;
+
+	if (num_cpus < 0)
+		return -EINVAL;
+
+	/* set cpu nums expected to be idled */
+	op.cmd = XENPF_core_parking;
+	op.u.core_parking.type = XEN_CORE_PARKING_SET;
+	op.u.core_parking.idle_nums = num_cpus;
+
+	return HYPERVISOR_dom0_op(&op);
+}
+
+/*
+ * Cannot get idle cpus by using hypercall once (shared with _SET)
+ * because of the characteristic of Xen continue_hypercall_on_cpu
+ */
+static int xen_pad_get_idle_cpus(void)
+{
+	int ret;
+	struct xen_platform_op op;
+
+	/* get cpu nums actually be idled */
+	op.cmd = XENPF_core_parking;
+	op.u.core_parking.type = XEN_CORE_PARKING_GET;
+	ret = HYPERVISOR_dom0_op(&op);
+	if (ret < 0)
+		return ret;
+
+	return op.u.core_parking.idle_nums;
+}
+
+/*
+ * 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 num_cpus;
+
+	num_cpus = xen_acpi_pad_pur(handle);
+	if (num_cpus < 0)
+		return;
+
+	mutex_lock(&xen_pad_lock);
+	if (xen_pad_set_idle_cpus(num_cpus)) {
+		mutex_unlock(&xen_pad_lock);
+		return;
+	}
+
+	num_cpus = xen_pad_get_idle_cpus();
+	if (num_cpus < 0) {
+		mutex_unlock(&xen_pad_lock);
+		return;
+	}
+	mutex_unlock(&xen_pad_lock);
+
+	xen_acpi_pad_ost(handle, 0, num_cpus);
+}
+
+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:
+		pr_warn("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)
+{
+	mutex_lock(&xen_pad_lock);
+	xen_pad_set_idle_cpus(0);
+	mutex_unlock(&xen_pad_lock);
+
+	acpi_remove_notify_handler(device->handle,
+		ACPI_DEVICE_NOTIFY, xen_acpi_pad_notify);
+	return 0;
+}
+
+static const struct acpi_device_id pad_device_ids[] = {
+	{"ACPI000C", 0},
+	{"", 0},
+};
+
+static struct acpi_driver xen_acpi_pad_driver = {
+	.name = "processor_aggregator",
+	.class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
+	.ids = pad_device_ids,
+	.ops = {
+		.add = xen_acpi_pad_add,
+		.remove = xen_acpi_pad_remove,
+	},
+};
+
+static int __init xen_acpi_pad_init(void)
+{
+	/* Only DOM0 is responsible for Xen acpi pad */
+	if (xen_initial_domain())
+		return acpi_bus_register_driver(&xen_acpi_pad_driver);
+
+	return -ENODEV;
+}
+subsys_initcall(xen_acpi_pad_init);
+
+#endif
diff --git a/include/xen/interface/platform.h b/include/xen/interface/platform.h
index 4755b5f..0f44376 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 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;
 };
-- 
1.7.1

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