@@ -910,7 +910,7 @@ static void __update_vcpu_system_time(struct vcpu *v, int force)
_u.tsc_timestamp = tsc_stamp;
_u.system_time = t->stime_local_stamp;
- if ( clocksource_is_tsc )
+ if ( clocksource_is_tsc || host_tsc_is_safe() )
_u.flags |= PVCLOCK_TSC_STABLE_BIT;
if ( is_hvm_domain(d) )
@@ -1378,6 +1378,15 @@ static void time_calibration_std_rendezvous(void *_r)
r->master_stime = read_platform_stime(&last_counter);
if ( clocksource_is_tsc )
r->master_tsc_stamp = last_counter;
+ else if ( host_tsc_is_safe() )
+ {
+ struct cpu_time *t = &this_cpu(cpu_time);
+ struct time_scale plt_scale_r =
+ scale_reciprocal(t->tsc_scale);
+
+ r->master_tsc_stamp = scale_delta(r->master_stime,
+ &plt_scale_r);
+ }
mb(); /* write r->master_stime /then/ signal */
atomic_inc(&r->semaphore);
}
@@ -1389,7 +1398,7 @@ static void time_calibration_std_rendezvous(void *_r)
mb(); /* receive signal /then/ read r->master_stime */
}
- if ( clocksource_is_tsc )
+ if ( clocksource_is_tsc || host_tsc_is_safe() )
c->local_tsc_stamp = r->master_tsc_stamp;
else
c->local_tsc_stamp = rdtsc();
This commit is an attempt at suporting PVCLOCK_TSC_STABLE_BIT when using other clocksources. master_tsc_stamp is set by converting master_stime (returned from read_platform_stime()) and converting it to a TSC by scaling the ns value accordingly. We scale the system time if TSC is reliable, and under the assumption there is a considerable skew between platform timer and TSC. In my machine I was measuring between -15 and 40 us between HPET and TSC. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> --- xen/arch/x86/time.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)