Re: [PATCH v2 4/9] KVM: s390: Fix dirty marking in adapter_indicators_set*()

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Wed, 12 Aug 2026 13:03:39 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> Am 12.08.26 um 12:44 schrieb Claudio Imbrenda:
> 
> > @@ -3017,26 +3017,30 @@ static int adapter_indicators_set_fast(struct kvm *kvm,
> >   				       struct kvm_s390_adapter_int *adapter_int,
> >   				       int setbit)
> >   {
> > +	struct s390_map_info *ind_info, *summary_info;
> >   	unsigned long bit;
> >   	int summary_set;
> > -	struct s390_map_info *ind_info, *summary_info;
> >   	void *map;
> >   
> > -	spin_lock(&adapter->maps_lock);
> > +	guard(srcu)(&kvm->srcu);
> > +	guard(spinlock)(&adapter->maps_lock);
> > +
> >   	ind_info = get_map_info(adapter, adapter_int->ind_addr);
> > -	if (!ind_info) {
> > -		spin_unlock(&adapter->maps_lock);
> > +	if (!ind_info)
> >   		return -EWOULDBLOCK;
> > -	}
> > +
> >   	map = page_address(ind_info->page);
> >   	bit = get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->swap);
> > -	if (setbit)
> > +	if (setbit) {
> > +		mark_page_dirty(kvm, gpa_to_gfn(adapter_int->ind_gaddr));
> > +		set_page_dirty(ind_info->page);
> >   		set_bit(bit, map);
> > +	}  
> 
> This marks the indicator page dirty before writing it.
> The summary twenty lines below does it the other way round and so do both
> slow-path branches.
> The order matters because kvm_get_dirty_log_protect() harvests destructively.

yes, that was a typo, but the patch also has other issues, so I'm
dropping it for now.