linux-kernel - Re: [PATCH 08/15] x86: Physical address comparisons in fill

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Message-ID: <3d750b58-d911-4f24-93e4-b84213849071@intel.com>
Date: Tue, 11 Feb 2025 11:59:15 -0800
From: Dave Hansen <dave.hansen@...el.com>
To: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
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Subject: Re: [PATCH 08/15] x86: Physical address comparisons in fill_p*d/pte

On 2/7/25 08:37, Maciej Wieczor-Retman wrote:
> @@ -287,7 +290,7 @@ static pte_t *fill_pte(pmd_t *pmd, unsigned long vaddr)
>  	if (pmd_none(*pmd)) {
>  		pte_t *pte = (pte_t *) spp_getpage();
>  		pmd_populate_kernel(&init_mm, pmd, pte);
> -		if (pte != pte_offset_kernel(pmd, 0))
> +		if (__pa(pte) != (pmd_val(*pmd) & pmd_pfn_mask(*pmd)))
>  			printk(KERN_ERR "PAGETABLE BUG #03!\n");
>  	}
>  	return pte_offset_kernel(pmd, vaddr);

Open coding it like this is fine with me.  The p*_offset_kernel(p*,0)
thing is arguably even harder to parse.