Re: [PATCH 00/19] Refresh queued CET virtualization series

From: Sean Christopherson
Date: Fri Jul 15 2022 - 11:58:25 EST

On Fri, Jul 15, 2022, Yang, Weijiang wrote:
> On 7/15/2022 3:36 AM, Sean Christopherson wrote:
> > It's definitely uncommon; unless I'm forgetting features, LA57 is the only feature
> > that KVM fully virtualizes (as opposed to emulates in software) without requiring
> > host enablement. Ah, and good ol' MPX, which is probably the best prior are since
> > it shares the same XSAVE+VMCS for user+supervisor state management. So more than
> > one, but still not very many.
> Speaking of MPX, is it really active in recent kernel? I can find little
> piece of code at native side, instead, more code in KVM.

Nope, native MPX support was ripped out a year or two ago. The kernel provides
just enough save+restore support so that KVM can continue to virtualize MPX.