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Commit dfd57bc3 authored by Stefano Stabellini's avatar Stefano Stabellini Committed by David Vrabel
Browse files

arm64: introduce CONFIG_PARAVIRT, PARAVIRT_TIME_ACCOUNTING and pv_time_ops 



Introduce CONFIG_PARAVIRT and PARAVIRT_TIME_ACCOUNTING on ARM64.
Necessary duplication of paravirt.h and paravirt.c with ARM.

The only paravirt interface supported is pv_time_ops.steal_clock, so no
runtime pvops patching needed.

This allows us to make use of steal_account_process_tick for stolen
ticks accounting.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 02c2433b

arch/arm64/Kconfig

+20 −0
Original line number Diff line number Diff line
@@ -556,6 +556,25 @@ config SECCOMP 
	  and the task is only allowed to execute a few safe syscalls

	  defined by each seccomp mode.



config PARAVIRT

	bool "Enable paravirtualization code"

	help

	  This changes the kernel so it can modify itself when it is run

	  under a hypervisor, potentially improving performance significantly

	  over full virtualization.



config PARAVIRT_TIME_ACCOUNTING

	bool "Paravirtual steal time accounting"

	select PARAVIRT

	default n

	help

	  Select this option to enable fine granularity task steal time

	  accounting. Time spent executing other tasks in parallel with

	  the current vCPU is discounted from the vCPU power. To account for

	  that, there can be a small performance impact.



	  If in doubt, say N here.



config XEN_DOM0

	def_bool y

	depends on XEN
@@ -564,6 +583,7 @@ config XEN 
	bool "Xen guest support on ARM64"

	depends on ARM64 && OF

	select SWIOTLB_XEN

	select PARAVIRT

	help

	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.

arch/arm64/include/asm/paravirt.h

0 → 100644
+20 −0
Original line number Diff line number Diff line 
#ifndef _ASM_ARM64_PARAVIRT_H

#define _ASM_ARM64_PARAVIRT_H



#ifdef CONFIG_PARAVIRT

struct static_key;

extern struct static_key paravirt_steal_enabled;

extern struct static_key paravirt_steal_rq_enabled;



struct pv_time_ops {

	unsigned long long (*steal_clock)(int cpu);

};

extern struct pv_time_ops pv_time_ops;



static inline u64 paravirt_steal_clock(int cpu)

{

	return pv_time_ops.steal_clock(cpu);

}

#endif



#endif

arch/arm64/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ arm64-obj-$(CONFIG_EFI) += efi.o efi-entry.stub.o 
arm64-obj-$(CONFIG_PCI)			+= pci.o

arm64-obj-$(CONFIG_ARMV8_DEPRECATED)	+= armv8_deprecated.o

arm64-obj-$(CONFIG_ACPI)		+= acpi.o

arm64-obj-$(CONFIG_PARAVIRT)		+= paravirt.o



obj-y					+= $(arm64-obj-y) vdso/

obj-m					+= $(arm64-obj-m)

arch/arm64/kernel/paravirt.c

0 → 100644
+25 −0
Original line number Diff line number Diff line 
/*

 * 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.  See the

 * GNU General Public License for more details.

 *

 * Copyright (C) 2013 Citrix Systems

 *

 * Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

 */



#include <linux/export.h>

#include <linux/jump_label.h>

#include <linux/types.h>

#include <asm/paravirt.h>



struct static_key paravirt_steal_enabled;

struct static_key paravirt_steal_rq_enabled;



struct pv_time_ops pv_time_ops;

EXPORT_SYMBOL_GPL(pv_time_ops);