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Commit b74f05d6 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

x86: kvmclock: abstract save/restore sched_clock_state 



Upon resume from hibernation, CPU 0's hvclock area contains the old
values for system_time and tsc_timestamp. It is necessary for the
hypervisor to update these values with uptodate ones before the CPU uses
them.

Abstract TSC's save/restore sched_clock_state functions and use
restore_state to write to KVM_SYSTEM_TIME MSR, forcing an update.

Also move restore_sched_clock_state before __restore_processor_state,
since the later calls CONFIG_LOCK_STAT's lockstat_clock (also for TSC).
Thanks to Igor Mammedov for tracking it down.

Fixes suspend-to-disk with kvmclock.

Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 95871901

arch/x86/include/asm/tsc.h

+2 −2
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ extern void check_tsc_sync_source(int cpu); 
extern void check_tsc_sync_target(void);



extern int notsc_setup(char *);

extern void save_sched_clock_state(void);

extern void restore_sched_clock_state(void);

extern void tsc_save_sched_clock_state(void);

extern void tsc_restore_sched_clock_state(void);



#endif /* _ASM_X86_TSC_H */

arch/x86/include/asm/x86_init.h

+4 −0
Original line number Diff line number Diff line
@@ -162,6 +162,8 @@ struct x86_cpuinit_ops { 
 * @is_untracked_pat_range	exclude from PAT logic

 * @nmi_init			enable NMI on cpus

 * @i8042_detect		pre-detect if i8042 controller exists

 * @save_sched_clock_state:	save state for sched_clock() on suspend

 * @restore_sched_clock_state:	restore state for sched_clock() on resume

 */

struct x86_platform_ops {

	unsigned long (*calibrate_tsc)(void);
@@ -173,6 +175,8 @@ struct x86_platform_ops { 
	void (*nmi_init)(void);

	unsigned char (*get_nmi_reason)(void);

	int (*i8042_detect)(void);

	void (*save_sched_clock_state)(void);

	void (*restore_sched_clock_state)(void);

};



struct pci_dev;

arch/x86/kernel/kvmclock.c

+11 −0
Original line number Diff line number Diff line
@@ -136,6 +136,15 @@ int kvm_register_clock(char *txt) 
	return ret;

}



static void kvm_save_sched_clock_state(void)

{

}



static void kvm_restore_sched_clock_state(void)

{

	kvm_register_clock("primary cpu clock, resume");

}



#ifdef CONFIG_X86_LOCAL_APIC

static void __cpuinit kvm_setup_secondary_clock(void)

{
@@ -195,6 +204,8 @@ void __init kvmclock_init(void) 
	x86_cpuinit.early_percpu_clock_init =

		kvm_setup_secondary_clock;

#endif

	x86_platform.save_sched_clock_state = kvm_save_sched_clock_state;

	x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state;

	machine_ops.shutdown  = kvm_shutdown;

#ifdef CONFIG_KEXEC

	machine_ops.crash_shutdown  = kvm_crash_shutdown;

arch/x86/kernel/tsc.c

+2 −2
Original line number Diff line number Diff line
@@ -629,7 +629,7 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) 


static unsigned long long cyc2ns_suspend;



void save_sched_clock_state(void)

void tsc_save_sched_clock_state(void)

{

	if (!sched_clock_stable)

		return;
@@ -645,7 +645,7 @@ void save_sched_clock_state(void) 
 * that sched_clock() continues from the point where it was left off during

 * suspend.

 */

void restore_sched_clock_state(void)

void tsc_restore_sched_clock_state(void)

{

	unsigned long long offset;

	unsigned long flags;

arch/x86/kernel/x86_init.c

+3 −1
Original line number Diff line number Diff line
@@ -108,7 +108,9 @@ struct x86_platform_ops x86_platform = { 
	.is_untracked_pat_range		= is_ISA_range,

	.nmi_init			= default_nmi_init,

	.get_nmi_reason			= default_get_nmi_reason,

	.i8042_detect			= default_i8042_detect

	.i8042_detect			= default_i8042_detect,

	.save_sched_clock_state 	= tsc_save_sched_clock_state,

	.restore_sched_clock_state 	= tsc_restore_sched_clock_state,

};



EXPORT_SYMBOL_GPL(x86_platform);