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 <mtosa...@redhat.com> Index: vsyscall/include/linux/pvclock_gtod.h =================================================================== --- /dev/null +++ vsyscall/include/linux/pvclock_gtod.h @@ -0,0 +1,9 @@ +#ifndef _PVCLOCK_GTOD_H +#define _PVCLOCK_GTOD_H + +#include <linux/notifier.h> + +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 +181,54 @@ static inline s64 timekeeping_get_ns_raw return nsec + arch_gettimeoffset(); } +static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); + +static void update_pvclock_gtod(struct timekeeper *tk) +{ + raw_notifier_call_chain(&pvclock_gtod_chain, 0, tk); +} + +/** + * 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); + /* update timekeeping data */ + update_pvclock_gtod(tk); + 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); + /* must hold write on timekeeper.lock */ static void timekeeping_update(struct timekeeper *tk, bool clearntp) { @@ -188,6 +237,7 @@ 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html