On 09/05/2016 10:22 AM, Borislav Petkov wrote:
> On Mon, Aug 22, 2016 at 05:36:46PM -0500, Tom Lendacky wrote:
>> Adding general kernel support for memory encryption includes:
>> - Modify and create some page table macros to include the Secure Memory
>>   Encryption (SME) memory encryption mask
>> - Update kernel boot support to call an SME routine that checks for and
>>   sets the SME capability (the SME routine will grow later and for now
>>   is just a stub routine)
>> - Update kernel boot support to call an SME routine that encrypts the
>>   kernel (the SME routine will grow later and for now is just a stub
>>   routine)
>> - Provide an SME initialization routine to update the protection map with
>>   the memory encryption mask so that it is used by default
>>
>> Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
> 
> ...
> 
>> diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
>> index c98a559..30f7715 100644
>> --- a/arch/x86/kernel/head_64.S
>> +++ b/arch/x86/kernel/head_64.S
>> @@ -95,6 +95,13 @@ startup_64:
>>      jnz     bad_address
>>  
>>      /*
>> +     * Enable memory encryption (if available). Add the memory encryption
>> +     * mask to %rbp to include it in the the page table fixup.
>> +     */
>> +    call    sme_enable
>> +    addq    sme_me_mask(%rip), %rbp
>> +
>> +    /*
>>       * Fixup the physical addresses in the page table
>>       */
>>      addq    %rbp, early_level4_pgt + (L4_START_KERNEL*8)(%rip)
>> @@ -116,7 +123,8 @@ startup_64:
>>      movq    %rdi, %rax
>>      shrq    $PGDIR_SHIFT, %rax
>>  
>> -    leaq    (4096 + _KERNPG_TABLE)(%rbx), %rdx
>> +    leaq    (4096 + __KERNPG_TABLE)(%rbx), %rdx
>> +    addq    sme_me_mask(%rip), %rdx         /* Apply mem encryption mask */
> 
> Please add comments over the line and not at the side...

Ok, will do.

Thanks,
Tom

> 
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