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Commit cbcf2dd3 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by John Stultz
Browse files

x86: kvm: Make kvm_get_time_and_clockread() nanoseconds based 



Convert the relevant base data right away to nanoseconds instead of
doing the conversion on every readout. Reduces text size by 160 bytes.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent bb0b5812

arch/x86/kvm/x86.c

+14 −30
Original line number Diff line number Diff line
@@ -984,9 +984,8 @@ struct pvclock_gtod_data { 
		u32	shift;

	} clock;



	/* open coded 'struct timespec' */

	u64		monotonic_time_snsec;

	time_t		monotonic_time_sec;

	u64		boot_ns;

	u64		nsec_base;

};



static struct pvclock_gtod_data pvclock_gtod_data;
@@ -994,6 +993,9 @@ static struct pvclock_gtod_data pvclock_gtod_data; 
static void update_pvclock_gtod(struct timekeeper *tk)

{

	struct pvclock_gtod_data *vdata = &pvclock_gtod_data;

	u64 boot_ns;



	boot_ns = ktime_to_ns(ktime_add(tk->base_mono, tk->offs_boot));



	write_seqcount_begin(&vdata->seq);
@@ -1004,17 +1006,8 @@ static void update_pvclock_gtod(struct timekeeper *tk) 
	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++;

	}

	vdata->boot_ns			= boot_ns;

	vdata->nsec_base		= tk->xtime_nsec;



	write_seqcount_end(&vdata->seq);

}
@@ -1371,23 +1364,22 @@ static inline u64 vgettsc(cycle_t *cycle_now) 
	return v * gtod->clock.mult;

}



static int do_monotonic(struct timespec *ts, cycle_t *cycle_now)

static int do_monotonic_boot(s64 *t, cycle_t *cycle_now)

{

	struct pvclock_gtod_data *gtod = &pvclock_gtod_data;

	unsigned long seq;

	u64 ns;

	int mode;

	struct pvclock_gtod_data *gtod = &pvclock_gtod_data;

	u64 ns;



	ts->tv_nsec = 0;

	do {

		seq = read_seqcount_begin(&gtod->seq);

		mode = gtod->clock.vclock_mode;

		ts->tv_sec = gtod->monotonic_time_sec;

		ns = gtod->monotonic_time_snsec;

		ns = gtod->nsec_base;

		ns += vgettsc(cycle_now);

		ns >>= gtod->clock.shift;

		ns += gtod->boot_ns;

	} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));

	timespec_add_ns(ts, ns);

	*t = ns;



	return mode;

}
@@ -1395,19 +1387,11 @@ static int do_monotonic(struct timespec *ts, cycle_t *cycle_now) 
/* returns true if host is using tsc clocksource */

static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now)

{

	struct timespec ts;



	/* checked again under seqlock below */

	if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)

		return false;



	if (do_monotonic(&ts, cycle_now) != VCLOCK_TSC)

		return false;



	monotonic_to_bootbased(&ts);

	*kernel_ns = timespec_to_ns(&ts);



	return true;

	return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;

}

#endif