PTP: add kvm PTP driver
Add a driver with gettime method returning hosts realtime clock.
This allows Chrony to synchronize host and guest clocks with
high precision (see results below).
chronyc> sources
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
To configure Chronyd to use PHC refclock, add the
following line to its configuration file:
refclock PHC /dev/ptpX poll 3 dpoll -2 offset 0
Where /dev/ptpX is the kvmclock PTP clock.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index bdce332..384f661 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -90,4 +90,16 @@
To compile this driver as a module, choose M here: the module
will be called ptp_pch.
+config PTP_1588_CLOCK_KVM
+ tristate "KVM virtual PTP clock"
+ depends on PTP_1588_CLOCK
+ depends on KVM_GUEST && X86
+ default y
+ help
+ This driver adds support for using kvm infrastructure as a PTP
+ clock. This clock is only useful if you are using KVM guests.
+
+ To compile this driver as a module, choose M here: the module
+ will be called ptp_kvm.
+
endmenu
