From 108b249c453dd7132599ab6dc7e435a7036c193f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 1 Sep 2016 14:21:03 +0200 Subject: KVM: x86: introduce get_kvmclock_ns Introduce a function that reads the exact nanoseconds value that is provided to the guest in kvmclock. This crystallizes the notion of kvmclock as a thin veneer over a stable TSC, that the guest will (hopefully) convert with NTP. In other words, kvmclock is *not* a paravirtualized host-to-guest NTP. Drop the get_kernel_ns() function, that was used both to get the base value of the master clock and to get the current value of kvmclock. The former use is replaced by ktime_get_boot_ns(), the latter is the purpose of get_kernel_ns(). This also allows KVM to provide a Hyper-V time reference counter that is synchronized with the time that is computed from the TSC page. Reviewed-by: Roman Kagan Signed-off-by: Paolo Bonzini --- arch/x86/kernel/pvclock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/pvclock.c') diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 3599404e3089..5b2cc889ce34 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -80,7 +80,7 @@ cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) do { version = pvclock_read_begin(src); - ret = __pvclock_read_cycles(src); + ret = __pvclock_read_cycles(src, rdtsc_ordered()); flags = src->flags; } while (pvclock_read_retry(src, version)); -- cgit v1.2.3