Re: [PATCH 0/4] KVM: Reset steal time accounting on vCPU pid change (x86 and arm64)
Marc Zyngier <[email protected]>
| Newsgroups | dev.linux.lists.kvmarm,org.kernel.vger.kvm,org.kernel.vger.linux-kselftest |
|---|---|
| Message-ID | <[email protected]> |
On Sun, 16 Aug 2026 06:33:01 +0100, Dongli Zhang <[email protected]> wrote: [...] > 4. Guest kernel changes are not included. I may send it separately to keep > this series limited to the KVM hypervisor. Hold on. Do you mean you are changing the guest visible behaviour of a PV interface? That's an ABI. It *cannot* change unilaterally. > > [PATCH 1/5] x86/kvm: Reset prev_steal_time and prev_steal_time_rq when enabling steal time > https://lore.kernel.org/all/[email protected] > > 5. There is one remaining corner case: this series resets last_steal when > the vCPU run PID changes, but not when steal time is enabled. If additional > host run_delay is accumulated after the PID changes but before the guest > enables steal time, that delta could be unexpectedly accounted to guest > vCPU steal time. In practice, this should not happen for Linux guests. Why is Linux immune to this? Also, KVM does not cater for Linux guests only. M. -- Without deviation from the norm, progress is not possible.