As suggested by John, export time data similarly to how its done by vsyscall support. This allows KVM to retrieve necessary information to implement vsyscall support in KVM guests.
Signed-off-by: Marcelo Tosatti <[email protected]> Index: vsyscall/include/linux/pvclock_gtod.h =================================================================== --- /dev/null +++ vsyscall/include/linux/pvclock_gtod.h @@ -0,0 +1,27 @@ +#ifndef _PVCLOCK_GTOD_H +#define _PVCLOCK_GTOD_H + +#include <linux/clocksource.h> +#include <linux/notifier.h> + +struct pvclock_gtod_data { + seqcount_t seq; + + struct { /* extract of a clocksource struct */ + int vclock_mode; + cycle_t cycle_last; + cycle_t mask; + u32 mult; + u32 shift; + } clock; + + /* open coded 'struct timespec' */ + u64 monotonic_time_snsec; + time_t monotonic_time_sec; +}; +extern struct pvclock_gtod_data pvclock_gtod_data; + +extern int pvclock_gtod_register_notifier(struct notifier_block *nb); +extern int pvclock_gtod_unregister_notifier(struct notifier_block *nb); + +#endif /* _PVCLOCK_GTOD_H */ Index: vsyscall/kernel/time/timekeeping.c =================================================================== --- vsyscall.orig/kernel/time/timekeeping.c +++ vsyscall/kernel/time/timekeeping.c @@ -21,6 +21,7 @@ #include <linux/time.h> #include <linux/tick.h> #include <linux/stop_machine.h> +#include <linux/pvclock_gtod.h> static struct timekeeper timekeeper; @@ -180,6 +181,79 @@ static inline s64 timekeeping_get_ns_raw return nsec + arch_gettimeoffset(); } +static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); + +/** + * pvclock_gtod_register_notifier - register a pvclock timedata update listener + * + * Must hold write on timekeeper.lock + */ +int pvclock_gtod_register_notifier(struct notifier_block *nb) +{ + struct timekeeper *tk = &timekeeper; + unsigned long flags; + int ret; + + write_seqlock_irqsave(&tk->lock, flags); + ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb); + write_sequnlock_irqrestore(&tk->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); + +/** + * pvclock_gtod_unregister_notifier - unregister a pvclock + * timedata update listener + * + * Must hold write on timekeeper.lock + */ +int pvclock_gtod_unregister_notifier(struct notifier_block *nb) +{ + struct timekeeper *tk = &timekeeper; + unsigned long flags; + int ret; + + write_seqlock_irqsave(&tk->lock, flags); + ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); + write_sequnlock_irqrestore(&tk->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); + +struct pvclock_gtod_data pvclock_gtod_data; +EXPORT_SYMBOL_GPL(pvclock_gtod_data); + +static void update_pvclock_gtod(struct timekeeper *tk) +{ + struct pvclock_gtod_data *vdata = &pvclock_gtod_data; + + write_seqcount_begin(&vdata->seq); + + /* copy pvclock gtod data */ + vdata->clock.vclock_mode = tk->clock->archdata.vclock_mode; + vdata->clock.cycle_last = tk->clock->cycle_last; + vdata->clock.mask = tk->clock->mask; + vdata->clock.mult = tk->mult; + vdata->clock.shift = tk->shift; + + vdata->monotonic_time_sec = tk->xtime_sec + + tk->wall_to_monotonic.tv_sec; + vdata->monotonic_time_snsec = tk->xtime_nsec + + (tk->wall_to_monotonic.tv_nsec + << tk->shift); + while (vdata->monotonic_time_snsec >= + (((u64)NSEC_PER_SEC) << tk->shift)) { + vdata->monotonic_time_snsec -= + ((u64)NSEC_PER_SEC) << tk->shift; + vdata->monotonic_time_sec++; + } + + write_seqcount_end(&vdata->seq); + raw_notifier_call_chain(&pvclock_gtod_chain, 0, NULL); +} + /* must hold write on timekeeper.lock */ static void timekeeping_update(struct timekeeper *tk, bool clearntp) { @@ -188,6 +262,7 @@ static void timekeeping_update(struct ti ntp_clear(); } update_vsyscall(tk); + update_pvclock_gtod(tk); } /** -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
