linux-kernel - Re: [PATCH v1 04/13] kho: Verify deserialization status and fix FDT alignment access

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Message-ID: <aRhJk_Glv2pX2dRo@kernel.org>
Date: Sat, 15 Nov 2025 11:36:19 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Pratyush Yadav <pratyush@...nel.org>
Cc: Pasha Tatashin <pasha.tatashin@...een.com>, akpm@...ux-foundation.org,
	bhe@...hat.com, jasonmiu@...gle.com, arnd@...db.de, coxu@...hat.com,
	dave@...ilevsky.ca, ebiggers@...gle.com, graf@...zon.com,
	kees@...nel.org, linux-kernel@...r.kernel.org,
	kexec@...ts.infradead.org, linux-mm@...ck.org
Subject: Re: [PATCH v1 04/13] kho: Verify deserialization status and fix FDT
 alignment access

On Fri, Nov 14, 2025 at 05:52:37PM +0100, Pratyush Yadav wrote:
> On Fri, Nov 14 2025, Pasha Tatashin wrote:
> 
> > @@ -1377,16 +1387,12 @@ static void __init kho_release_scratch(void)
> >  
> >  void __init kho_memory_init(void)
> >  {
> > -	struct folio *folio;
> > -
> >  	if (kho_in.scratch_phys) {
> >  		kho_scratch = phys_to_virt(kho_in.scratch_phys);
> >  		kho_release_scratch();
> >  
> > -		kho_mem_deserialize(kho_get_fdt());
> > -		folio = kho_restore_folio(kho_in.fdt_phys);
> > -		if (!folio)
> > -			pr_warn("failed to restore folio for KHO fdt\n");
> > +		if (!kho_mem_deserialize(kho_get_fdt()))
> > +			kho_in.fdt_phys = 0;
> 
> The folio restore does serve a purpose: it accounts for that folio in
> the system's total memory. See the call to adjust_managed_page_count()
> in kho_restore_page(). In practice, I don't think it makes much of a
> difference, but I don't see why not.

This page is never freed, so adding it to zone managed pages or keeping it
reserved does not change anything.
 
> >  	} else {
> >  		kho_reserve_scratch();
> >  	}
> 
> -- 
> Regards,
> Pratyush Yadav

-- 
Sincerely yours,
Mike.