Re: [PATCH v1 03/11] KVM: x86: dynamic kvm_apic_map

Andrew Honig
2016-06-30T22:16:08Z

> -
> - new = kzalloc(sizeof(struct kvm_apic_map), GFP_KERNEL);
> + u32 size, max_id = 255;
>
> mutex_lock(&kvm->arch.apic_map_lock);
>
> + kvm_for_each_vcpu(i, vcpu, kvm)
> + if (kvm_apic_present(vcpu))
> + max_id = max(max_id, kvm_apic_id(vcpu->arch.apic));
> +
> + /* kvm_apic_map_get_logical_dest() expects multiples of 16 */
> + size = round_up(max_id + 1, 16);

Now that you're using the full range of apic_id values, could this
calculation overflow? Perhaps max_id could be u64?

> + new = kzalloc(sizeof(struct kvm_apic_map) +
> + sizeof(struct kvm_lapic) * size, GFP_KERNEL);
> +
> if (!new)
> goto out;
>