[PATCH v4 10/14] KVM: arm64: Calculate cptr_el2 traps on activating traps

[Fuad Tabba]

On Wed, 11 Dec 2024 at 12:46, Quentin Perret <qperret at google.com> wrote:
>
> On Monday 02 Dec 2024 at 15:47:37 (+0000), Fuad Tabba wrote:
> > -static void pvm_init_traps_cptr(struct kvm_vcpu *vcpu)
> > -{
> > -     struct kvm *kvm = vcpu->kvm;
> > -     u64 val = vcpu->arch.cptr_el2;
> > -
> > -     if (!has_hvhe()) {
> > -             val |= CPTR_NVHE_EL2_RES1;
> > -             val &= ~(CPTR_NVHE_EL2_RES0);
> > -     }
> > -
> > -     if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, AMU, IMP))
> > -             val |= CPTR_EL2_TAM;
> > -
> > -     /* SVE can be disabled by userspace even if supported. */
> > -     if (!vcpu_has_sve(vcpu)) {
> > -             if (has_hvhe())
> > -                     val &= ~(CPACR_ELx_ZEN);
> > -             else
> > -                     val |= CPTR_EL2_TZ;
> > -     }
> > -
> > -     /* No SME support in KVM. */
> > -     BUG_ON(kvm_has_feat(kvm, ID_AA64PFR1_EL1, SME, IMP));
> > -     if (has_hvhe())
> > -             val &= ~(CPACR_ELx_SMEN);
> > -     else
> > -             val |= CPTR_EL2_TSM;
> > -
> > -     if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceVer, IMP)) {
> > -             if (has_hvhe())
> > -                     val |= CPACR_EL1_TTA;
> > -             else
> > -                     val |= CPTR_EL2_TTA;
> > -     }
> > -
> > -     vcpu->arch.cptr_el2 = val;
> > -}
>
> Mooh, wasn't this function added in this very series? Not a huge deal,
> but is there any way we could consolidate things a bit?

Yes it was, but it was added when I was doing the grouping in Patch
02, without changing the actual trapping, to make that commit easier
to read. If I were to consolidate them then Patch 02 would be changing
more than one thing at the same time, making it (imo) more difficult
to reason about things...

/fuad