Commit Graph

3 Commits

Author SHA1 Message Date
kbuild test robot 49e190ec33 PTP: fix ptr_ret.cocci warnings
drivers/ptp/ptp_kvm.c:229:1-3: WARNING: PTR_ERR_OR_ZERO can be used

 Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR

Generated by: scripts/coccinelle/api/ptr_ret.cocci

CC: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-03-20 16:25:06 +01:00
Radim Krčmář 4306f200c7 ptp_kvm: try to detect hypercall availability
No point in registering the device if it cannot work.
The hypercall does not advertise itself, so we have to call it.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-02-16 18:42:17 +01:00
Marcelo Tosatti a0e136d436 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>
2017-02-08 17:16:20 +01:00