Re: [PATCHv2 1/7] mm: Add support for unaccepted memory

[Mike Rapoport <rppt@kernel.org>]

On Wed, Jan 12, 2022 at 10:40:53AM -0800, Dave Hansen wrote:
> On 1/12/22 10:30, Kirill A. Shutemov wrote:
> > On Tue, Jan 11, 2022 at 11:46:37AM -0800, Dave Hansen wrote:
> > > > diff --git a/mm/memblock.c b/mm/memblock.c
> > > > index 1018e50566f3..6dfa594192de 100644
> > > > --- a/mm/memblock.c
> > > > +++ b/mm/memblock.c
> > > > @@ -1400,6 +1400,7 @@ phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
> > > >    		 */
> > > >    		kmemleak_alloc_phys(found, size, 0, 0);
> > > > +	accept_memory(found, found + size);
> > > >    	return found;
> > > >    }
> > > 
> > > This could use a comment.
> > 
> > How about this:
> > 
> > 	/*
> > 	 * Some Virtual Machine platforms, such as Intel TDX or AMD SEV-SNP,
> > 	 * requiring memory to be accepted before it can be used by the
> > 	 * guest.
> > 	 *
> > 	 * Accept the memory of the allocated buffer.
> > 	 */
> 
> I think a one-liner that might cue the reader to go look at accept_memory()
> itself would be fine.  Maybe:
> 
> 	/* Make the memblock usable when running in picky VM guests: */

I'd s/memblock/found range/ or something like that, memblock is too vague
IMO
 
> That implies that the memory isn't usable without doing this and also points
> out that it's related to running in a guest.

-- 
Sincerely yours,
Mike.