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    Subject[patch V2 44/64] 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: Thomas Gleixner <tglx@linutronix.de>
    Cc: Gleb Natapov <gleb@kernel.org>
    Cc: kvm@vger.kernel.org
    ---
    arch/x86/kvm/x86.c | 44 ++++++++++++++------------------------------
    1 file changed, 14 insertions(+), 30 deletions(-)

    Index: tip/arch/x86/kvm/x86.c
    ===================================================================
    --- tip.orig/arch/x86/kvm/x86.c
    +++ tip/arch/x86/kvm/x86.c
    @@ -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_
    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 t
    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
    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
    /* 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




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