On 02/16/2018 10:25 AM, Nadav Amit wrote: >> +#ifdef CONFIG_PAGE_TABLE_ISOLATION >> +#define __PAGE_KERNEL_GLOBAL 0 >> +#else >> +#define __PAGE_KERNEL_GLOBAL _PAGE_GLOBAL >> +#endif > ... >> --- 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? That's a good point. The current patch does not allow the use of _PAGE_GLOBAL via _PAGE_KERNEL_GLOBAL when CONFIG_PAGE_TABLE_ISOLATION=y, but booted with nopti. It's a simple enough fix. Logically: #ifdef CONFIG_PAGE_TABLE_ISOLATION #define __PAGE_KERNEL_GLOBAL static_cpu_has(X86_FEATURE_PTI) ? 0 : _PAGE_GLOBAL #else #define __PAGE_KERNEL_GLOBAL _PAGE_GLOBAL #endif But I don't really want to hide that gunk in a macro like that. It might make more sense as a static inline. I'll give that a shot and resent. -- 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>
