| Subject | Re: [PATCH v5 09/32] x86/mm: Provide general kernel support for memory encryption | From | Dave Hansen <> | Date | Fri, 21 Apr 2017 14:52:21 -0700 |
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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.
How does that end up ever happening? If we are pulling physical addresses out of the page tables, we use p??_phys(). I'd expect *those* to be masking off the SME bits.
Is it these cases?
pgd_t *base = __va(read_cr3());
For those, it seems like we really want to create two modes of reading cr3. One that truly reads CR3 and another that reads the pgd's physical address out of CR3. Then you only do the SME masking on the one fetching a physical address, and the SME bits never leak into __va().
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