On Tue, 18 Jan 2022 11:24:04 +0000,
Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
>
>
> On 30-11-2021 01:31 am, Marc Zyngier wrote:
> > +struct kvm_s2_mmu *lookup_s2_mmu(struct kvm *kvm, u64 vttbr, u64 hcr)
> > +{
> > + bool nested_stage2_enabled = hcr & HCR_VM;
> > + int i;
> > +
> > + /* Don't consider the CnP bit for the vttbr match */
> > + vttbr = vttbr & ~VTTBR_CNP_BIT;
> > +
> > + /*
> > + * Two possibilities when looking up a S2 MMU context:
> > + *
> > + * - either S2 is enabled in the guest, and we need a context that
> > + * is S2-enabled and matches the full VTTBR (VMID+BADDR), which
> > + * makes it safe from a TLB conflict perspective (a broken guest
> > + * won't be able to generate them),
> > + *
> > + * - or S2 is disabled, and we need a context that is S2-disabled
> > + * and matches the VMID only, as all TLBs are tagged by VMID even
> > + * if S2 translation is enabled.
>
> I think you were intended to say "if S2 translation is disabled".
Yes, absolutely. Good catch.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
