Re: [PATCH v10 16/50] x86/sev: Introduce snp leaked pages list

[Kalra, Ashish]

On 12/6/2023 2:42 PM, Borislav Petkov wrote:
> On Mon, Oct 16, 2023 at 08:27:45AM -0500, Michael Roth wrote:
> > +	spin_lock(&snp_leaked_pages_list_lock);
> > +	while (npages--) {
> > +		/*
> > +		 * Reuse the page's buddy list for chaining into the leaked
> > +		 * pages list. This page should not be on a free list currently
> > +		 * and is also unsafe to be added to a free list.
> > +		 */
> > +		list_add_tail(&page->buddy_list, &snp_leaked_pages_list);
> > +		sev_dump_rmpentry(pfn);
> > +		pfn++;
> > +	}
> > +	spin_unlock(&snp_leaked_pages_list_lock);
> > +	atomic_long_inc(&snp_nr_leaked_pages);
>
> How is this supposed to count?
>
> You're leaking @npages as the function's parameter but are incrementing
> snp_nr_leaked_pages only once?
>
> Just make it a bog-normal unsigned long and increment it inside the
> locked section.
>
> Or do at the beginning of the function:
>
> 	atomic_long_add(npages, &snp_nr_leaked_pages);

Yes will fix accordingly by incrementing it inside the locked section.

Thanks,
Ashish