Re: [FYI PATCH] Revert "KVM: x86/mmu: Zap only TDP MMU leafs in kvm_zap_gfn_range()"

Sean Christopherson
2022-03-25T20:22:45Z

On Fri, Mar 25, 2022, Paolo Bonzini wrote:
> On 3/25/22 00:57, Sean Christopherson wrote:
> > Can I have 1-2 weeks to try and root cause and fix the underlying issue before
> > sending reverts to Linus? I really don't want to paper over a TLB flushing bug
> > or an off-by-one bug, and I really, really don't want to end up with another
> > scenario where KVM zaps everything just because.
>
> Well, too late... I didn't want to send a pull request that was broken,

Ah, I didn't see that it was in the initial pull request, thought it was only in
kvm/next. I'll send a full patch.

> Mingwei provided a convincing reason for the breakage.

No, the side effects are completely benign, and arguably desirable. The issue is
that KVM loses a pending TLB flush if there are multiple roots.