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| author | Paolo Bonzini <pbonzini@redhat.com> | 2016-09-01 15:21:03 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-09-20 10:26:15 +0300 |
| commit | 108b249c453dd7132599ab6dc7e435a7036c193f (patch) | |
| tree | eb600c0558d7032bc1b0c62066f74ac109bd4fd7 /arch/x86/entry | |
| parent | 67198ac3f37ffb150f1c95fae16b597339eabc9d (diff) | |
| download | linux-108b249c453dd7132599ab6dc7e435a7036c193f.tar.xz | |
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 <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/vdso/vclock_gettime.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 94d54d0defa7..02223cb4bcfd 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -129,7 +129,7 @@ static notrace cycle_t vread_pvclock(int *mode) return 0; } - ret = __pvclock_read_cycles(pvti); + ret = __pvclock_read_cycles(pvti, rdtsc_ordered()); } while (pvclock_read_retry(pvti, version)); /* refer to vread_tsc() comment for rationale */ |