Re: [PATCH v15 12/13] x86/kvmclock: Abort SecureTSC enabled guest when kvmclock is selected

Nikunj A. Dadhania
2025-01-02T05:34:41Z

On 1/1/2025 9:49 PM, Borislav Petkov wrote:
> On Wed, Jan 01, 2025 at 03:14:12PM +0530, Nikunj A. Dadhania wrote:
>> I can drop this patch, and if the admin wants to change the clock
>> source to kvm-clock from Secure TSC, that will be permitted.
>
> Why would the admin want that and why would we even support that?

I am not saying that admin will do that, I am saying that it is a possibility.

Changing clocksource is supported via sysfs interface:

echo "kvm-clock" > /sys/devices/system/clocksource/clocksource0/current_clocksource

This is what we are trying to prevent in this patch.

Regards,
Nikunj