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Date: Wed, 10 Apr 2024 19:19:44 +0200
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-s390@vger.kernel.org, kvm@vger.kernel.org,
        Matthew Wilcox
 <willy@infradead.org>,
        Heiko Carstens <hca@linux.ibm.com>, Vasily Gorbik
 <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Christian
 Borntraeger <borntraeger@linux.ibm.com>,
        Sven Schnelle
 <svens@linux.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>,
        Gerald
 Schaefer <gerald.schaefer@linux.ibm.com>,
        Thomas Huth <thuth@redhat.com>
Subject: Re: [PATCH v1 4/5] s390/uv: update PG_arch_1 comment
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In-Reply-To: <20240404163642.1125529-5-david@redhat.com>
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	<20240404163642.1125529-5-david@redhat.com>
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On Thu,  4 Apr 2024 18:36:41 +0200
David Hildenbrand <david@redhat.com> wrote:

> We removed the usage of PG_arch_1 for page tables in commit
> a51324c430db ("s390/cmma: rework no-dat handling").
> 
> Let's update the comment in UV to reflect that.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

> ---
>  arch/s390/kernel/uv.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
> index 9c0113b26735..76fc61333fae 100644
> --- a/arch/s390/kernel/uv.c
> +++ b/arch/s390/kernel/uv.c
> @@ -471,13 +471,12 @@ int arch_make_page_accessible(struct page *page)
>  		return 0;
>  
>  	/*
> -	 * PG_arch_1 is used in 3 places:
> -	 * 1. for kernel page tables during early boot
> -	 * 2. for storage keys of huge pages and KVM
> -	 * 3. As an indication that this small folio might be secure. This can
> +	 * PG_arch_1 is used in 2 places:
> +	 * 1. for storage keys of hugetlb folios and KVM
> +	 * 2. As an indication that this small folio might be secure. This can
>  	 *    overindicate, e.g. we set the bit before calling
>  	 *    convert_to_secure.
> -	 * As secure pages are never huge, all 3 variants can co-exists.
> +	 * As secure pages are never large folios, both variants can co-exists.
>  	 */
>  	if (!test_bit(PG_arch_1, &folio->flags))
>  		return 0;