Messages in this thread | | | Date | Wed, 27 Apr 2016 05:40:52 -0400 | From | Gerg Kurz <> | Subject | Re: [PATCH v4 1/2] KVM: remove NULL return path for vcpu ids >= KVM_MAX_VCPUS |
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Quoting Greg Kurz <gkurz@linux.vnet.ibm.com>:
> Commit c896939f7cff ("KVM: use heuristic for fast VCPU lookup by id") added > a return path that prevents vcpu ids to exceed KVM_MAX_VCPUS. This is a > problem for powerpc where vcpu ids can grow up to 8*KVM_MAX_VCPUS. > > This patch simply reverses the logic so that we only try fast path if the > vcpu id can be tried as an index in kvm->vcpus[]. The slow path is not > affected by the change. > > Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> > ---
Radim,
I think this sanity check is only needed because kvm_get_vcpu() use the id as an index in kvm->vcpus[]. Checking against the new KVM_MAX_VCPU_ID would be clearly wrong here.
And this patch got two R-b tags already. Do you agree we keep it ?
Cheers.
-- Greg
> include/linux/kvm_host.h | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 5276fe0916fc..23bfe1bd159c 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -447,12 +447,13 @@ static inline struct kvm_vcpu > *kvm_get_vcpu(struct kvm *kvm, int i) > > static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id) > { > - struct kvm_vcpu *vcpu; > + struct kvm_vcpu *vcpu = NULL; > int i; > > - if (id < 0 || id >= KVM_MAX_VCPUS) > + if (id < 0) > return NULL; > - vcpu = kvm_get_vcpu(kvm, id); > + if (id < KVM_MAX_VCPUS) > + vcpu = kvm_get_vcpu(kvm, id); > if (vcpu && vcpu->vcpu_id == id) > return vcpu; > kvm_for_each_vcpu(i, vcpu, kvm) > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
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