On 09/08/2016 08:55 AM, Borislav Petkov wrote: > On Thu, Sep 08, 2016 at 08:26:27AM -0500, Tom Lendacky wrote: >> When does this value get initialized? Since _PAGE_ENC is #defined to >> sme_me_mask, which is not set until the boot process begins, I'm afraid >> we'd end up using the initial value of sme_me_mask, which is zero. Do >> I have that right? > > Hmm, but then that would hold true for all the other defines where you > OR-in _PAGE_ENC, no? As long as the #define is not a global variable like this one it's ok. > > In any case, the preprocessed source looks like this: > > pmdval_t early_pmd_flags = (((((((pteval_t)(1)) << 0) | (((pteval_t)(1)) << 1) | (((pteval_t)(1)) << 6) | (((pteval_t)(1)) << 5) | (((pteval_t)(1)) << 8)) | (((pteval_t)(1)) << 63)) | (((pteval_t)(1)) << 7)) | sme_me_mask) & ~((((pteval_t)(1)) << 8) | (((pteval_t)(1)) << 63)); > > but the problem is later, when building: > > arch/x86/kernel/head64.c:39:28: error: initializer element is not constant > pmdval_t early_pmd_flags = (__PAGE_KERNEL_LARGE | _PAGE_ENC) & ~(_PAGE_GLOBAL | _PAGE_NX); > ^ > scripts/Makefile.build:153: recipe for target 'arch/x86/kernel/head64.s' failed > > so I guess not. :-\ > > Ok, then at least please put the early_pmd_flags init after > sme_early_init() along with a small comment explaning what happens. Let me verify that we won't possibly take any kind of page fault during sme_early_init() and cause a page to be not be marked encrypted. Or... I can add a comment indicating I need to set this as early as possible to cover any page faults that might occur. Thanks, Tom > > Thanks. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>