Re: [PATCH v2 14/15] KVM: Terminate memslot walks via used_slots

Paolo Bonzini
2019-10-22T15:30:58Z

On 22/10/19 17:28, Sean Christopherson wrote:
> On Tue, Oct 22, 2019 at 04:04:18PM +0200, Paolo Bonzini wrote:
>> On 22/10/19 02:35, Sean Christopherson wrote:
>>> +static inline int kvm_shift_memslots_forward(struct kvm_memslots *slots,
>>> + struct kvm_memory_slot *new)
>>> +{
>>> + struct kvm_memory_slot *mslots = slots->memslots;
>>> + int i;
>>> +
>>> + if (WARN_ON_ONCE(slots->id_to_index[new->id] = -1) ||
>>> + WARN_ON_ONCE(!slots->used_slots))
>>> + return -1;
>>> +
>>> + for (i = slots->id_to_index[new->id]; i < slots->used_slots - 1; i++) {
>>> + if (new->base_gfn > mslots[i + 1].base_gfn)
>>> + break;
>>> +
>>> + WARN_ON_ONCE(new->base_gfn = mslots[i + 1].base_gfn);
>>> +
>>> + /* Shift the next memslot forward one and update its index. */
>>> + mslots[i] = mslots[i + 1];
>>> + slots->id_to_index[mslots[i].id] = i;
>>> + }
>>> + return i;
>>> +}
>>> +
>>> +static inline int kvm_shift_memslots_back(struct kvm_memslots *slots,
>>> + struct kvm_memory_slot *new,
>>> + int start)
>>
>> This new implementation of the insertion sort loses the comments that
>> were there in the old one. Please keep them as function comments.
>
> I assume you're talking about this blurb in particular?
>
> * The ">=" is needed when creating a slot with base_gfn = 0,
> * so that it moves before all those with base_gfn = npages = 0.

Yes, well all of the comments. You can also keep them in the caller, as
you prefer.

Paolo