Re: [PATCH v5 09/32] x86/mm: Provide general kernel support for memory encryption

Dave Hansen
2017-04-24T15:57:28Z

On 04/24/2017 08:53 AM, Tom Lendacky wrote:
> On 4/21/2017 4:52 PM, Dave Hansen wrote:
>> On 04/18/2017 02:17 PM, Tom Lendacky wrote:
>>> @@ -55,7 +57,7 @@ static inline void copy_user_page(void *to, void
>>> *from, unsigned long vaddr,
>>> __phys_addr_symbol(__phys_reloc_hide((unsigned long)(x)))
>>>
>>> #ifndef __va
>>> -#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
>>> +#define __va(x) ((void *)(__sme_clr(x) + PAGE_OFFSET))
>>> #endif
>>
>> It seems wrong to be modifying __va(). It currently takes a physical
>> address, and this modifies it to take a physical address plus the SME
>> bits.
>
> This actually modifies it to be sure the encryption bit is not part of
> the physical address.

If SME bits make it this far, we have a bug elsewhere. Right? Probably
best not to paper over it.