linux-kernel - Re: [PATCH v6 3/5] x86/mm: add .data..decrypted section to hold shared variables

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Date:   Mon, 10 Sep 2018 07:33:13 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     Borislav Petkov <bp@...e.de>
Cc:     brijesh.singh@....com, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: Re: [PATCH v6 3/5] x86/mm: add .data..decrypted section to hold
 shared variables



On 9/10/18 6:54 AM, Borislav Petkov wrote:
...

>> @@ -487,28 +510,69 @@ static void __init teardown_workarea_map(struct sme_workarea_data *wa,
>>  	native_write_cr3(__native_read_cr3());
>>  }
>>  
>> +static void __init decrypt_shared_data(struct sme_workarea_data *wa,
>> +				       struct sme_populate_pgd_data *ppd)
>> +{
>> +	unsigned long decrypted_start, decrypted_end, decrypted_len;
>> +
>> +	/* Physical addresses of decrypted data section */
>> +	decrypted_start = __pa_symbol(__start_data_decrypted);
>> +	decrypted_end = ALIGN(__pa_symbol(__end_data_decrypted), PMD_PAGE_SIZE);
> Why?
>
> You have:
>
> +       . = ALIGN(PMD_SIZE);                                    \
> +       __end_data_decrypted = .;                               \
>
> It is already aligned by definition?!?
>

Right, there is no need to use ALIGN. I will remove it.

-Brijesh