4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> commit 38669ba205d178d2d38bfd194a196d65a44d5af2 upstream. It is expected for sched_clock() to output data from 0, when system boots. Add an offset xen_sched_clock_offset (similarly how it is done in other hypervisors i.e. kvm_sched_clock_offset) to count sched_clock() from 0, when time is first initialized. Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: steven.sistare@xxxxxxxxxx Cc: daniel.m.jordan@xxxxxxxxxx Cc: linux@xxxxxxxxxxxxxxx Cc: schwidefsky@xxxxxxxxxx Cc: heiko.carstens@xxxxxxxxxx Cc: john.stultz@xxxxxxxxxx Cc: sboyd@xxxxxxxxxxxxxx Cc: hpa@xxxxxxxxx Cc: douly.fnst@xxxxxxxxxxxxxx Cc: peterz@xxxxxxxxxxxxx Cc: prarit@xxxxxxxxxx Cc: feng.tang@xxxxxxxxx Cc: pmladek@xxxxxxxx Cc: gnomes@xxxxxxxxxxxxxxxxxxx Cc: linux-s390@xxxxxxxxxxxxxxx Cc: boris.ostrovsky@xxxxxxxxxx Cc: jgross@xxxxxxxx Cc: pbonzini@xxxxxxxxxx Link: https://lkml.kernel.org/r/20180719205545.16512-14-pasha.tatashin@xxxxxxxxxx Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/xen/time.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -31,6 +31,8 @@ /* Xen may fire a timer up to this many ns early */ #define TIMER_SLOP 100000 +static u64 xen_sched_clock_offset __read_mostly; + /* Get the TSC speed from Xen */ static unsigned long xen_tsc_khz(void) { @@ -57,6 +59,11 @@ static u64 xen_clocksource_get_cycles(st return xen_clocksource_read(); } +static u64 xen_sched_clock(void) +{ + return xen_clocksource_read() - xen_sched_clock_offset; +} + static void xen_read_wallclock(struct timespec *ts) { struct shared_info *s = HYPERVISOR_shared_info; @@ -367,7 +374,7 @@ void xen_timer_resume(void) } static const struct pv_time_ops xen_time_ops __initconst = { - .sched_clock = xen_clocksource_read, + .sched_clock = xen_sched_clock, .steal_clock = xen_steal_clock, }; @@ -505,6 +512,7 @@ static void __init xen_time_init(void) void __ref xen_init_time_ops(void) { + xen_sched_clock_offset = xen_clocksource_read(); pv_time_ops = xen_time_ops; x86_init.timers.timer_init = xen_time_init; @@ -547,6 +555,7 @@ void __init xen_hvm_init_time_ops(void) return; } + xen_sched_clock_offset = xen_clocksource_read(); pv_time_ops = xen_time_ops; x86_init.timers.setup_percpu_clockev = xen_time_init; x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
