| Message ID | 20170124171020.310170535@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 24/01/2017 18:09, Marcelo Tosatti wrote: > Expose the realtime host clock and save the TSC value > used for the clock calculation. > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> > > --- > arch/x86/kvm/x86.c | 36 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 36 insertions(+) > > v2: unify nsec_base (Radim) > > Index: kvm-ptpdriver/arch/x86/kvm/x86.c > =================================================================== > --- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 16:43:15.013244682 -0200 > +++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-20 09:56:41.404534904 -0200 > @@ -1139,6 +1139,7 @@ > > u64 boot_ns; > u64 nsec_base; > + u64 wall_time_sec; > }; > > static struct pvclock_gtod_data pvclock_gtod_data; > @@ -1162,6 +1163,8 @@ > vdata->boot_ns = boot_ns; > vdata->nsec_base = tk->tkr_mono.xtime_nsec; > > + vdata->wall_time_sec = tk->xtime_sec; > + > write_seqcount_end(&vdata->seq); > } > #endif > @@ -1623,6 +1626,28 @@ > return mode; > } > > +static int do_realtime(struct timespec *ts, cycle_t *cycle_now) > +{ > + struct pvclock_gtod_data *gtod = &pvclock_gtod_data; > + unsigned long seq; > + int mode; > + u64 ns; > + > + do { > + seq = read_seqcount_begin(>od->seq); > + mode = gtod->clock.vclock_mode; > + ts->tv_sec = gtod->wall_time_sec; > + ns = gtod->nsec_base; > + ns += vgettsc(cycle_now); > + ns >>= gtod->clock.shift; > + } while (unlikely(read_seqcount_retry(>od->seq, seq))); > + > + ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); > + ts->tv_nsec = ns; > + > + return mode; > +} > + > /* returns true if host is using tsc clocksource */ > static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) > { > @@ -1632,6 +1657,17 @@ > > return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC; > } > + > +/* returns true if host is using tsc clocksource */ > +static bool kvm_get_walltime_and_clockread(struct timespec *ts, > + cycle_t *cycle_now) > +{ > + /* checked again under seqlock below */ > + if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC) > + return false; > + > + return do_realtime(ts, cycle_now) == VCLOCK_TSC; > +} > #endif > > /* > > > Only used in the next patch, will squash. Also, cycle_t is gone now so use u64 instead. Paolo
Index: kvm-ptpdriver/arch/x86/kvm/x86.c =================================================================== --- kvm-ptpdriver.orig/arch/x86/kvm/x86.c 2017-01-13 16:43:15.013244682 -0200 +++ kvm-ptpdriver/arch/x86/kvm/x86.c 2017-01-20 09:56:41.404534904 -0200 @@ -1139,6 +1139,7 @@ u64 boot_ns; u64 nsec_base; + u64 wall_time_sec; }; static struct pvclock_gtod_data pvclock_gtod_data; @@ -1162,6 +1163,8 @@ vdata->boot_ns = boot_ns; vdata->nsec_base = tk->tkr_mono.xtime_nsec; + vdata->wall_time_sec = tk->xtime_sec; + write_seqcount_end(&vdata->seq); } #endif @@ -1623,6 +1626,28 @@ return mode; } +static int do_realtime(struct timespec *ts, cycle_t *cycle_now) +{ + struct pvclock_gtod_data *gtod = &pvclock_gtod_data; + unsigned long seq; + int mode; + u64 ns; + + do { + seq = read_seqcount_begin(>od->seq); + mode = gtod->clock.vclock_mode; + ts->tv_sec = gtod->wall_time_sec; + ns = gtod->nsec_base; + ns += vgettsc(cycle_now); + ns >>= gtod->clock.shift; + } while (unlikely(read_seqcount_retry(>od->seq, seq))); + + ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); + ts->tv_nsec = ns; + + return mode; +} + /* returns true if host is using tsc clocksource */ static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now) { @@ -1632,6 +1657,17 @@ return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC; } + +/* returns true if host is using tsc clocksource */ +static bool kvm_get_walltime_and_clockread(struct timespec *ts, + cycle_t *cycle_now) +{ + /* checked again under seqlock below */ + if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC) + return false; + + return do_realtime(ts, cycle_now) == VCLOCK_TSC; +} #endif /*
Expose the realtime host clock and save the TSC value used for the clock calculation. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> --- arch/x86/kvm/x86.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) v2: unify nsec_base (Radim)