Commit 898ec52d authored Jul 21, 2020 by Hayato Ohhashi Committed by Ingo Molnar Jul 25, 2020

x86/xen/time: Set the X86_FEATURE_TSC_KNOWN_FREQ flag in xen_tsc_khz()



If the TSC frequency is known from the pvclock page,
the TSC frequency does not need to be recalibrated.

We can avoid recalibration by setting X86_FEATURE_TSC_KNOWN_FREQ.

Signed-off-by: Hayato Ohhashi <o8@vmm.dev>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20200721161231.6019-1-o8@vmm.dev

parent 23ee3e4e

arch/x86/xen/time.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,7 @@ static unsigned long xen_tsc_khz(void)
		struct pvclock_vcpu_time_info *info =
		&HYPERVISOR_shared_info->vcpu_info[0].time;

		setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
		return pvclock_tsc_khz(info);
		}

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