On 02/16/2018 10:25 AM, Nadav Amit wrote: >> --- a/arch/x86/mm/pageattr.c~kpti-no-global-for-kernel-mappings >> 2018-02-13 15:17:56.148210060 -0800 >> +++ b/arch/x86/mm/pageattr.c 2018-02-13 15:17:56.153210060 -0800 >> @@ -593,7 +593,8 @@ try_preserve_large_page(pte_t *kpte, uns >> * different bit positions in the two formats. >> */ >> req_prot = pgprot_4k_2_large(req_prot); >> - req_prot = pgprot_set_on_present(req_prot, _PAGE_GLOBAL | _PAGE_PSE); >> + req_prot = pgprot_set_on_present(req_prot, >> + __PAGE_KERNEL_GLOBAL | _PAGE_PSE); >> req_prot = canon_pgprot(req_prot); > From these chunks, it seems to me as req_prot will not have the global bit > on when “nopti” parameter is provided. What am I missing?
BTW, this code is broken. It's trying to unconditionally set _PAGE_GLOBAL whenever set do change_page_attr() and friends. It gets fixed up by canon_pgprot(), but it's wrong to do in the first place. I've got a better fix for this coming.
