linux-kernel - [PATCH] x86/mm: Avoid paravirtualization calls in native_set

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Date:   Wed, 28 Feb 2018 18:00:22 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>
Cc:     Fengguang Wu <fengguang.wu@...el.com>,
        linux-kernel@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCH] x86/mm: Avoid paravirtualization calls in native_set_p4d()

p4d_val() and pgd_val() are paravirtualized and we should avoid using
them in native_set_p4d().

Let's replace them with native_p4d_val() and native_pgd_val().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Reported-by: Fengguang Wu <fengguang.wu@...el.com>
Fixes: 91f606a8fa68 ("x86/mm: Replace compile-time checks for 5-level paging with runtime-time checks")
---
 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)
-- 
2.16.1