Messages in this thread | | | Subject | Re: [RFC PATCH v4 07/28] x86: Provide general kernel support for memory encryption | From | Tom Lendacky <> | Date | Thu, 23 Feb 2017 17:12:38 -0600 |
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On 2/22/2017 12:13 PM, Dave Hansen wrote: > On 02/16/2017 07:43 AM, Tom Lendacky wrote: >> static inline unsigned long pte_pfn(pte_t pte) >> { >> - return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT; >> + return (pte_val(pte) & ~sme_me_mask & PTE_PFN_MASK) >> PAGE_SHIFT; >> } >> >> static inline unsigned long pmd_pfn(pmd_t pmd) >> { >> - return (pmd_val(pmd) & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; >> + return (pmd_val(pmd) & ~sme_me_mask & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; >> } > > Could you talk a bit about why you chose to do the "~sme_me_mask" bit in > here instead of making it a part of PTE_PFN_MASK / pmd_pfn_mask(pmd)?
I think that's a good catch. Let me look at it, but I believe that it should be possible to do and avoid what you're worried about below.
Thanks, Tom
> > It might not matter, but I'd be worried that this ends up breaking > direct users of PTE_PFN_MASK / pmd_pfn_mask(pmd) since they now no > longer mask the PFN out of a PTE. >
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