On Fri, Nov 18, 2022, Paolo Bonzini wrote:
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 43bbe4fde078..5d85f1a61793 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1603,6 +1603,8 @@ static int kvm_prepare_memory_region(struct kvm *kvm,
> struct kvm_memory_slot *new,
> enum kvm_mr_change change)
> {
> + int old_flags = old ? old->flags : 0;
> + int new_flags = new ? new->flags : 0;
> int r;
>
> /*
> @@ -1627,6 +1629,11 @@ static int kvm_prepare_memory_region(struct kvm *kvm,
> }
> }
>
> + if ((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES) {
> + int change = (new_flags & KVM_MEM_LOG_DIRTY_PAGES) ? 1 : -1;
> + atomic_set(&kvm->nr_memslots_dirty_logging,
> + atomic_read(&kvm->nr_memslots_dirty_logging) + change);
Again, this needs to be done in the "commit" stage, and IMO should be x86-only.
https://lore.kernel.org/all/Y3bTu4%2FnUfpX+Enm@xxxxxxxxxx
> + }
> r = kvm_arch_prepare_memory_region(kvm, old, new, change);
>
> /* Free the bitmap on failure if it was allocated above. */
> --
> 2.31.1
>
