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Commit 6f4151c8 authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Thomas Gleixner
Browse files

x86: Hyper-V: Integrate the clocksource with Hyper-V detection code 



The Hyper-V clocksource driver is best integrated with Hyper-V
detection code since: 

  (a) Linux guests running on Hyper-V require it

  (b) Integration into that code significanly reduces code size

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Cc: gregkh@suse.de
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.osdl.org
Link: http://lkml.kernel.org/r/1315434310-4827-1-git-send-email-kys@microsoft.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent ddf28352

arch/x86/kernel/cpu/mshyperv.c

+23 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ 
 */



#include <linux/types.h>

#include <linux/time.h>

#include <linux/clocksource.h>

#include <linux/module.h>

#include <asm/processor.h>

#include <asm/hypervisor.h>
@@ -36,6 +38,25 @@ static bool __init ms_hyperv_platform(void) 
		!memcmp("Microsoft Hv", hyp_signature, 12);

}



static cycle_t read_hv_clock(struct clocksource *arg)

{

	cycle_t current_tick;

	/*

	 * Read the partition counter to get the current tick count. This count

	 * is set to 0 when the partition is created and is incremented in

	 * 100 nanosecond units.

	 */

	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);

	return current_tick;

}



static struct clocksource hyperv_cs = {

	.name		= "hyperv_clocksource",

	.rating		= 400, /* use this when running on Hyperv*/

	.read		= read_hv_clock,

	.mask		= CLOCKSOURCE_MASK(64),

};



static void __init ms_hyperv_init_platform(void)

{

	/*
@@ -46,6 +67,8 @@ static void __init ms_hyperv_init_platform(void) 


	printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",

	       ms_hyperv.features, ms_hyperv.hints);



	clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);

}



const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {

drivers/staging/hv/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_HYPERV)		+= hv_vmbus.o hv_timesource.o

obj-$(CONFIG_HYPERV)		+= hv_vmbus.o

obj-$(CONFIG_HYPERV_STORAGE)	+= hv_storvsc.o

obj-$(CONFIG_HYPERV_BLOCK)	+= hv_blkvsc.o

obj-$(CONFIG_HYPERV_NET)	+= hv_netvsc.o

drivers/staging/hv/hv_timesource.c

deleted100644 → 0
+0 −101
Original line number Diff line number Diff line 
/*

 * A clocksource for Linux running on HyperV.

 *

 *

 * Copyright (C) 2010, Novell, Inc.

 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/clocksource.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/dmi.h>

#include <asm/hyperv.h>

#include <asm/mshyperv.h>

#include <asm/hypervisor.h>



#define HV_CLOCK_SHIFT	22



static cycle_t read_hv_clock(struct clocksource *arg)

{

	cycle_t current_tick;

	/*

	 * Read the partition counter to get the current tick count. This count

	 * is set to 0 when the partition is created and is incremented in

	 * 100 nanosecond units.

	 */

	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);

	return current_tick;

}



static struct clocksource hyperv_cs = {

	.name           = "hyperv_clocksource",

	.rating         = 400, /* use this when running on Hyperv*/

	.read           = read_hv_clock,

	.mask           = CLOCKSOURCE_MASK(64),

	/*

	 * The time ref counter in HyperV is in 100ns units.

	 * The definition of mult is:

	 * mult/2^shift = ns/cyc = 100

	 * mult = (100 << shift)

	 */

	.mult           = (100 << HV_CLOCK_SHIFT),

	.shift          = HV_CLOCK_SHIFT,

};



static const struct dmi_system_id __initconst

hv_timesource_dmi_table[] __maybe_unused  = {

	{

		.ident = "Hyper-V",

		.matches = {

			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),

			DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),

			DMI_MATCH(DMI_BOARD_NAME, "Virtual Machine"),

		},

	},

	{ },

};

MODULE_DEVICE_TABLE(dmi, hv_timesource_dmi_table);



static const struct pci_device_id __initconst

hv_timesource_pci_table[] __maybe_unused = {

	{ PCI_DEVICE(0x1414, 0x5353) }, /* VGA compatible controller */

	{ 0 }

};

MODULE_DEVICE_TABLE(pci, hv_timesource_pci_table);





static int __init init_hv_clocksource(void)

{

	if ((x86_hyper != &x86_hyper_ms_hyperv) ||

		!(ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE))

		return -ENODEV;



	if (!dmi_check_system(hv_timesource_dmi_table))

		return -ENODEV;



	pr_info("Registering HyperV clock source\n");

	return clocksource_register(&hyperv_cs);

}



module_init(init_hv_clocksource);

MODULE_DESCRIPTION("HyperV based clocksource");

MODULE_AUTHOR("K. Y. Srinivasan <ksrinivasan@novell.com>");

MODULE_LICENSE("GPL");