Re: [PATCH RFCv1 4/8] kvm: Introduce secondary dirty bitmap

[Juan Quintela]

Gavin Shan <gshan@redhat.com> wrote:
> When dirty ring is enabled on ARM64, the backup bitmap may be used
> to track the dirty pages in no-running-vcpu situations. The original
> bitmap is the primary one, used for the dirty ring buffer. We need
> the secondary bitmap to collect the backup bitmap for ARM64.
>
> No functional change intended.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  accel/kvm/kvm-all.c      | 50 ++++++++++++++++++++++++++++++----------
>  include/sysemu/kvm_int.h |  1 +
>  2 files changed, 39 insertions(+), 12 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 01a6a026af..1a93985574 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -553,13 +553,29 @@ static void kvm_log_stop(MemoryListener *listener,
>      }
>  }
>  
> +static unsigned long *kvm_slot_dirty_bitmap(KVMSlot *slot, bool primary)
> +{
> +    if (primary) {
> +        return slot->dirty_bmap;
> +    }
> +
> +    return slot->dirty_bmap +
> +           slot->dirty_bmap_size / sizeof(slot->dirty_bmap[0]);
> +}


Why?
Just use two bitmaps and call it a day.

Later, Juan.