Messages in this thread Patch in this message | | | From | Jeremy Fitzhardinge <> | Subject | [PATCH 04/12] kvm/pvclock: add monotonicity check | Date | Wed, 14 Oct 2009 12:28:28 -0700 |
| |
Other tsc-based clocksources add a monotonicity test to make sure there's no regression in the returned cycles.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Avi Kivity <avi@redhat.com> --- arch/x86/kernel/kvmclock.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 223af43..46cb77f 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -77,9 +77,14 @@ static cycle_t kvm_clock_read(void) return ret; } +static struct clocksource kvm_clock; + static cycle_t kvm_clock_get_cycles(struct clocksource *cs) { - return kvm_clock_read(); + cycle_t ret = kvm_clock_read(); + + return ret >= kvm_clock.cycle_last ? + ret : kvm_clock.cycle_last; } /* -- 1.6.2.5
| |