On 02/13/2012 02:07 PM, Marcelo Tosatti wrote:
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.
Signed-off-by: Marcelo Tosatti<mtosatti@xxxxxxxxxx>
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 15d9915..c91e8b9 100644
--- 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 5d0afac..baaca8d 100644
--- 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 ca4e735..57e6b78 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -136,6 +136,15 @@ int kvm_register_clock(char *txt)
return ret;
}
+void kvm_save_sched_clock_state(void)
+{
+}
+
+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 a62c201..aed2aa1 100644
--- 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 6f2ec53..e9f265f 100644
--- 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 f10c0af..0e76a28 100644
--- 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();
Isn't it too early? It is scarry to say hypervisor to write to some
memory location and than completely replace page-tables and half of
cpu state in __restore_processor_state. Wouldn't that have a potential
of writing into a place that is not restored hv_clock and restored
hv_clock might still be stale?
__restore_processor_state(&saved_context);
- restore_sched_clock_state();
}
#ifdef CONFIG_X86_32
EXPORT_SYMBOL(restore_processor_state);
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--
Thanks,
Igor
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