From: David Woodhouse <d...@amazon.co.uk> The VMCLOCK device gives support for accurate timekeeping even across live migration, unlike the KVM PTP clock. To help ensure that users can always use ptp_vmclock where it's available in preference to ptp_kvm, set it to 'default PTP_1588_CLOCK_VMCLOCK' instead of 'default y'.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
drivers/ptp/Kconfig | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index e98c9767e0ef..ed087ae75f0e 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -135,12 +135,16 @@ config PTP_1588_CLOCK_VMCLOCK
tristate "Virtual machine PTP clock"
depends on X86_TSC || ARM_ARCH_TIMER
depends on PTP_1588_CLOCK && ACPI && ARCH_SUPPORTS_INT128
- default y
+ default PTP_1588_CLOCK_KVM
help
This driver adds support for using a virtual precision clock
advertised by the hypervisor. This clock is only useful in virtual
machines where such a device is present.
+ Unlike the KVM virtual PTP clock, the VMCLOCK device offers support
+ for reliable timekeeping even across live migration. So this driver
+ is enabled by default whenever the KVM PTP clock is.
+
To compile this driver as a module, choose M here: the module
will be called ptp_vmclock.
--
2.44.0
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