From a5b162b2ecb013ed517ab5ce90079117ada743f4 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Mon, 5 Mar 2018 11:16:41 +0300 Subject: [PATCH] x86/mm: Do not use paravirtualized calls in native_set_p4d() In 4-level paging mode, native_set_p4d() updates the entry in the top-level page table. With PTI, update to the top-level kernel page table requires update to the userspace copy of the table as well, using pti_set_user_pgd(). native_set_p4d() uses p4d_val() and pgd_val() to convert types between p4d_t and pgd_t. p4d_val() and pgd_val() are paravirtualized and we must not use them in native helpers, as they crash the boot in paravirtualized environments. Replace p4d_val() and pgd_val() with native_p4d_val() and native_pgd_val() in native_set_p4d(). Reported-by: Fengguang Wu Signed-off-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 91f606a8fa68 ("x86/mm: Replace compile-time checks for 5-level paging with runtime-time checks") Link: http://lkml.kernel.org/r/20180305081641.4290-1-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/pgtable_64.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index 81dda8d1d0bd..163e01a0631d 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -224,9 +224,9 @@ static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d) return; } - pgd = native_make_pgd(p4d_val(p4d)); + pgd = native_make_pgd(native_p4d_val(p4d)); pgd = pti_set_user_pgd((pgd_t *)p4dp, pgd); - *p4dp = native_make_p4d(pgd_val(pgd)); + *p4dp = native_make_p4d(native_pgd_val(pgd)); } static inline void native_p4d_clear(p4d_t *p4d)