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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 15d99153a96d31a52a72dd69a4f73ddd93373fc8..c91e8b9d588b14d0f86b4ea7a82b5d07c8387c2c 100644 (file)
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -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 */

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 5d0afac2962cf0510207b62ed60c5428619429a4..baaca8defec8032463d1a87d53137a8c88f63639 100644 (file)
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -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;

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index ca4e735adc5472f6b863d7fbd3f84b3e5b184144..f8492da65bfcb03e2775638ad5ce9502099d62c8 100644 (file)
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -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;

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index a62c201c97eccf31fa90d05dec5e5cf5102ead74..aed2aa1088f11cd5c0838fbdef0920bdb2afe6d3 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -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;

diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index 6f2ec53deed0b9a477bcf9bdd630b025e227c009..e9f265fd79ae11db4d5234e7b7462134c6220619 100644 (file)
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -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);

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index f10c0afa1cb4ceb6fdd34cd0f5e2a352f192cad5..0e76a2814127154f31bc4b373ed2bbbb95425f8d 100644 (file)
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -114,7 +114,7 @@ static void __save_processor_state(struct saved_context *ctxt)
 void save_processor_state(void)
 {
        __save_processor_state(&saved_context);
-       save_sched_clock_state();
+       x86_platform.save_sched_clock_state();
 }
 #ifdef CONFIG_X86_32
 EXPORT_SYMBOL(save_processor_state);
@@ -230,8 +230,8 @@ static void __restore_processor_state(struct saved_context *ctxt)
 /* Needed by apm.c */
 void restore_processor_state(void)
 {
+       x86_platform.restore_sched_clock_state();
        __restore_processor_state(&saved_context);
-       restore_sched_clock_state();
 }
 #ifdef CONFIG_X86_32
 EXPORT_SYMBOL(restore_processor_state);