linux-kernel - Re: [PATCH] X86: __set_clr_pte_enc() miscalculates physical address

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Date:   Mon, 22 Mar 2021 16:02:11 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Isaku Yamahata <isaku.yamahata@...el.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        x86@...nel.org, kvm@...r.kernel.org
Cc:     brijesh.singh@....com, tglx@...utronix.de, bp@...en8.de,
        isaku.yamahata@...il.com,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH] X86: __set_clr_pte_enc() miscalculates physical address

On 3/18/21 3:26 PM, Isaku Yamahata wrote:
> __set_clr_pte_enc() miscalculates physical address to operate.
> pfn is in unit of PG_LEVEL_4K, not PGL_LEVEL_{2M, 1G}.
> Shift size to get physical address should be PAGE_SHIFT,
> not page_level_shift().
> 
> Fixes: dfaaec9033b8 ("x86: Add support for changing memory encryption attribute in early boot")
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@....com>

> ---
>  arch/x86/mm/mem_encrypt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 4b01f7dbaf30..ae78cef79980 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -262,7 +262,7 @@ static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
>  	if (pgprot_val(old_prot) == pgprot_val(new_prot))
>  		return;
>  
> -	pa = pfn << page_level_shift(level);
> +	pa = pfn << PAGE_SHIFT;
>  	size = page_level_size(level);
>  
>  	/*
>