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Date:   Tue, 26 Jul 2022 11:07:14 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <seanjc@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Joerg Roedel <jroedel@suse.de>,
        Ard Biesheuvel <ardb@kernel.org>,
        Andi Kleen <ak@linux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
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        Dave Hansen <dave.hansen@intel.com>,
        Mike Rapoport <rppt@kernel.org>,
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        x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev,
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        Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCHv7 08/14] x86/mm: Reserve unaccepted memory bitmap
Message-ID: <Yt+uwhfA57WBrozb@zn.tnic>
References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com>
 <20220614120231.48165-9-kirill.shutemov@linux.intel.com>
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On Tue, Jun 14, 2022 at 03:02:25PM +0300, Kirill A. Shutemov wrote:
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index f267205f2d5a..22d1fe48dcba 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -1316,6 +1316,16 @@ void __init e820__memblock_setup(void)
>  	int i;
>  	u64 end;
>  
> +	/* Mark unaccepted memory bitmap reserved */
> +	if (boot_params.unaccepted_memory) {
> +		unsigned long size;
> +
> +		/* One bit per 2MB */
> +		size = DIV_ROUND_UP(e820__end_of_ram_pfn() * PAGE_SIZE,
> +				    PMD_SIZE * BITS_PER_BYTE);
> +		memblock_reserve(boot_params.unaccepted_memory, size);
> +	}
> +

Hmm, I don't like how this is dropped right in the middle of a unrelated
function.

You're adding arch/x86/mm/unaccepted_memory.c later. Why don't you put
that chunk in a function there which is called by early_reserve_memory()
which does exactly what you want - reserve memory early, before memblock
allocations?

Hmm.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette