Re: [EARLY RFC] KVM: SVM: Enable AVIC by default from Zen 4

From: Sean Christopherson
Date: Tue Aug 19 2025 - 19:54:43 EST


On Tue, Aug 19, 2025, Maciej S. Szmigiero wrote:
> On 18.07.2025 10:19, Naveen N Rao wrote:
> As you can see, currently AVIC works there even without force_avic=1 so why
> now hide it behind that parameter if errata #1235 is supposedly not present
> on Zen3?

Yeah, I'm aligned with keeping the current semantics for force_avic (and by
extension for avic), and I'm pretty sure Naveen is as well.

> Also, this platform is apparently confident enough that the AVIC silicon is
> working correctly there to expose it in CPUID - maybe because that's CPU
> stepping 2 instead of the initial 0?

My vote is still to only enable AVIC by default for Zen4+. The story for Zen3
and earlier is just too messy.