On 01/18/2018 01:56 PM, Claudio Imbrenda wrote:
> These are some utilty functions that will be used later on for storage
> attributes migration.
>
> Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxxxxxxx>
> ---
> arch/s390/kvm/kvm-s390.c | 32 ++++++++++++++++++++++++++++++++
> arch/s390/kvm/kvm-s390.h | 6 ++++++
> 2 files changed, 38 insertions(+)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 6f17031..5a69334 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -1512,6 +1512,38 @@ static long kvm_s390_set_skeys(struct kvm *kvm, struct kvm_s390_skeys *args)
> #define KVM_S390_CMMA_SIZE_MAX ((u32)KVM_S390_SKEYS_MAX)
>
> /*
> + * Similar to gfn_to_memslot, but returns a memslot also when the address falls
gfn_to_memslot returns a memslot, this returns an int?
> + * in a hole. In that case a memslot near the hole is returned.
Can you please clarify that statement? Will it be the slot that is closest
in terms of bytes or what? Maybe also provide a use case and an example
> + */
> +static int gfn_to_memslot_approx(struct kvm *kvm, gfn_t gfn)
> +{
> + struct kvm_memslots *slots = kvm_memslots(kvm);
> + int start = 0, end = slots->used_slots;
> + int slot = atomic_read(&slots->lru_slot);
> + struct kvm_memory_slot *memslots = slots->memslots;
> +
> + if (gfn >= memslots[slot].base_gfn &&
> + gfn < memslots[slot].base_gfn + memslots[slot].npages)
> + return slot;
> +
> + while (start < end) {
> + slot = start + (end - start) / 2;
> +
> + if (gfn >= memslots[slot].base_gfn)
> + end = slot;
> + else
> + start = slot + 1;
> + }
> +
> + if (gfn >= memslots[start].base_gfn &&
> + gfn < memslots[start].base_gfn + memslots[start].npages) {
> + atomic_set(&slots->lru_slot, start);
> + }
Another question for Paolo/Radim. In case we need such function, would
it be better in common code (kvm_main.c)
> +
> + return start;
> +}
> +
> +/*
> * This function searches for the next page with dirty CMMA attributes, and
> * saves the attributes in the buffer up to either the end of the buffer or
> * until a block of at least KVM_S390_MAX_BIT_DISTANCE clean bits is found;
> diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
> index 04a3e91..b86c1ad 100644
> --- a/arch/s390/kvm/kvm-s390.h
> +++ b/arch/s390/kvm/kvm-s390.h
> @@ -183,6 +183,12 @@ static inline int kvm_s390_user_cpu_state_ctrl(struct kvm *kvm)
> return kvm->arch.user_cpu_state_ctrl != 0;
> }
>
> +static inline unsigned long *cmma_bitmap(struct kvm_memory_slot *slot)
> +{
> + return slot->dirty_bitmap +
> + kvm_dirty_bitmap_bytes(slot) / sizeof(*slot->dirty_bitmap);
> +}
> +
Hmmm, in virt/kvm/kvm_main.c we do have in kvm_get_dirty_log_protect
n = kvm_dirty_bitmap_bytes(memslot);
dirty_bitmap_buffer = dirty_bitmap + n / sizeof(long);
Does it make sense to have that helper common (and call it maybe
unsigned long *kvm_get_shadow_dirty(struct kvm_memory_slot *slot)
