Re: [PATCH v6 00/51] x86: Try to wrangle PV clocks vs. TSC

[David Woodhouse]

On Thu, 2026-09-10 at 10:59 -0700, Sean Christopherson wrote:
> On Thu, Aug 06, 2026, Sean Christopherson wrote:
> > The primary goal of this series to fix flaws with SNP and TDX guests where a
> > PV clock provided by the untrusted hypervisor is used instead of the secure
> > TSC that is controlled by trusted firmware.
> > 
> > The secondary goal is modernize running under KVM.  Currently, KVM guests will
> > use TSC for clocksource, but not sched_clock.  And Linux-as-a-KVM-guest doesn't
> > support paravirt enumeration of the TSC/APIC frequencies, even though QEMU
> > provides that information by default.
> > 
> > The tertiary goal is to clean up the PV clock code to deduplicate logic across
> > hypervisors, and to hopefully make it all easier to maintain going forward.
> > 
> > The quaternary goal is to clean up the TSC calibration code, which was made
> > stupidly hard to follow by hypervisor code mixing in with the native
> > calibration routines, instead of being implemented as a pure alternative.
> > 
> > Note, the VMware and Xen changes still probably should get acks from those
> > maintainers, as my understanding of what they're trying to do may be flawed.
> 
> This (thankfully) still applies cleanly.  What can I do to help move this forward?

Nudge Thomas to spot that this is guest-side and we want him to pick it up, I guess?

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