Commit a0e2bf7c authored by Juergen Gross's avatar Juergen Gross Committed by Borislav Petkov
Browse files

x86/paravirt: Switch time pvops functions to use static_call() 



The time pvops functions are the only ones left which might be
used in 32-bit mode and which return a 64-bit value.

Switch them to use the static_call() mechanism instead of pvops, as
this allows quite some simplification of the pvops implementation.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311142319.4723-5-jgross@suse.com
parent 6ea312d9

arch/arm/include/asm/paravirt.h

+5 −9
Original line number Original line Diff line number Diff line
@@ -3,23 +3,19 @@ 
#define _ASM_ARM_PARAVIRT_H

#define _ASM_ARM_PARAVIRT_H





#ifdef CONFIG_PARAVIRT

#ifdef CONFIG_PARAVIRT

#include <linux/static_call_types.h>



struct static_key;

struct static_key;

extern struct static_key paravirt_steal_enabled;

extern struct static_key paravirt_steal_enabled;

extern struct static_key paravirt_steal_rq_enabled;

extern struct static_key paravirt_steal_rq_enabled;





struct pv_time_ops {

u64 dummy_steal_clock(int cpu);

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

};



struct paravirt_patch_template {

	struct pv_time_ops time;

};





extern struct paravirt_patch_template pv_ops;

DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);





static inline u64 paravirt_steal_clock(int cpu)

static inline u64 paravirt_steal_clock(int cpu)

{

{

	return pv_ops.time.steal_clock(cpu);

	return static_call(pv_steal_clock)(cpu);

}

}

#endif

#endif

arch/arm/kernel/paravirt.c

+7 −2
Original line number Original line Diff line number Diff line
@@ -9,10 +9,15 @@ 
#include <linux/export.h>

#include <linux/export.h>

#include <linux/jump_label.h>

#include <linux/jump_label.h>

#include <linux/types.h>

#include <linux/types.h>

#include <linux/static_call.h>

#include <asm/paravirt.h>

#include <asm/paravirt.h>





struct static_key paravirt_steal_enabled;

struct static_key paravirt_steal_enabled;

struct static_key paravirt_steal_rq_enabled;

struct static_key paravirt_steal_rq_enabled;





struct paravirt_patch_template pv_ops;

static u64 native_steal_clock(int cpu)

EXPORT_SYMBOL_GPL(pv_ops);
 
{

	return 0;

}



DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);

arch/arm64/include/asm/paravirt.h

+5 −9
Original line number Original line Diff line number Diff line
@@ -3,23 +3,19 @@ 
#define _ASM_ARM64_PARAVIRT_H

#define _ASM_ARM64_PARAVIRT_H





#ifdef CONFIG_PARAVIRT

#ifdef CONFIG_PARAVIRT

#include <linux/static_call_types.h>



struct static_key;

struct static_key;

extern struct static_key paravirt_steal_enabled;

extern struct static_key paravirt_steal_enabled;

extern struct static_key paravirt_steal_rq_enabled;

extern struct static_key paravirt_steal_rq_enabled;





struct pv_time_ops {

u64 dummy_steal_clock(int cpu);

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

};



struct paravirt_patch_template {

	struct pv_time_ops time;

};





extern struct paravirt_patch_template pv_ops;

DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);





static inline u64 paravirt_steal_clock(int cpu)

static inline u64 paravirt_steal_clock(int cpu)

{

{

	return pv_ops.time.steal_clock(cpu);

	return static_call(pv_steal_clock)(cpu);

}

}





int __init pv_time_init(void);

int __init pv_time_init(void);

arch/arm64/kernel/paravirt.c

+9 −4
Original line number Original line Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/reboot.h>

#include <linux/reboot.h>

#include <linux/slab.h>

#include <linux/slab.h>

#include <linux/types.h>

#include <linux/types.h>

#include <linux/static_call.h>





#include <asm/paravirt.h>

#include <asm/paravirt.h>

#include <asm/pvclock-abi.h>

#include <asm/pvclock-abi.h>
@@ -26,8 +27,12 @@ 
struct static_key paravirt_steal_enabled;

struct static_key paravirt_steal_enabled;

struct static_key paravirt_steal_rq_enabled;

struct static_key paravirt_steal_rq_enabled;





struct paravirt_patch_template pv_ops;

static u64 native_steal_clock(int cpu)

EXPORT_SYMBOL_GPL(pv_ops);

{

	return 0;

}



DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);





struct pv_time_stolen_time_region {

struct pv_time_stolen_time_region {

	struct pvclock_vcpu_stolen_time *kaddr;

	struct pvclock_vcpu_stolen_time *kaddr;
@@ -45,7 +50,7 @@ static int __init parse_no_stealacc(char *arg) 
early_param("no-steal-acc", parse_no_stealacc);

early_param("no-steal-acc", parse_no_stealacc);





/* return stolen time in ns by asking the hypervisor */

/* return stolen time in ns by asking the hypervisor */

static u64 pv_steal_clock(int cpu)

static u64 para_steal_clock(int cpu)

{

{

	struct pv_time_stolen_time_region *reg;

	struct pv_time_stolen_time_region *reg;
@@ -150,7 +155,7 @@ int __init pv_time_init(void) 
	if (ret)

	if (ret)

		return ret;

		return ret;





	pv_ops.time.steal_clock = pv_steal_clock;

	static_call_update(pv_steal_clock, para_steal_clock);





	static_key_slow_inc(&paravirt_steal_enabled);

	static_key_slow_inc(&paravirt_steal_enabled);

	if (steal_acc)

	if (steal_acc)

arch/x86/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -777,6 +777,7 @@ if HYPERVISOR_GUEST 




config PARAVIRT

config PARAVIRT

	bool "Enable paravirtualization code"

	bool "Enable paravirtualization code"

	depends on HAVE_STATIC_CALL

	help

	help

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

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

	  under a hypervisor, potentially improving performance significantly

	  under a hypervisor, potentially improving performance significantly