[net-next] ptp: Remove 'default y' for VMCLOCK PTP device

Commit Message

David Woodhouse Nov. 2, 2024, 9:52 p.m. UTC

From: David Woodhouse <[e-mail]>

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 <[e-mail]>
---
 drivers/ptp/Kconfig | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Jakub Kicinski Nov. 5, 2024, 2:19 a.m. UTC | #1

On Sat, 02 Nov 2024 16:52:17 -0500 David Woodhouse wrote:
> From: David Woodhouse <[e-mail]>
> 
> 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'.

Good enough for me, let's see if it's good enough for the main guy :)
Thanks!

[e-mail] Nov. 5, 2024, 2:20 a.m. UTC | #2

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <[e-mail]>:

On Sat, 02 Nov 2024 16:52:17 -0500 you wrote:
> From: David Woodhouse <[e-mail]>
> 
> 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'.
> 
> [...]

Here is the summary with links:
  - [net-next] ptp: Remove 'default y' for VMCLOCK PTP device
    https://git.kernel.org/netdev/net-next/c/18ec5491a495

You are awesome, thank you!

Patch

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.