linux-kernel - [tip: x86/paravirt] x86/paravirt: Avoid needless paravirt step clearing page table entries

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Message-ID: <159750640968.3192.2279401610614202728.tip-bot2@tip-bot2>
Date:   Sat, 15 Aug 2020 15:46:49 -0000
From:   "tip-bot2 for Juergen Gross" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Juergen Gross <jgross@...e.com>, Ingo Molnar <mingo@...nel.org>,
        x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: x86/paravirt] x86/paravirt: Avoid needless paravirt step
 clearing page table entries

The following commit has been merged into the x86/paravirt branch of tip:

Commit-ID:     7c9f80cb76ec9f14c3b25509168b1a2f7942e418
Gitweb:        https://git.kernel.org/tip/7c9f80cb76ec9f14c3b25509168b1a2f7942e418
Author:        Juergen Gross <jgross@...e.com>
AuthorDate:    Sat, 15 Aug 2020 12:06:41 +02:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Sat, 15 Aug 2020 13:52:12 +02:00

x86/paravirt: Avoid needless paravirt step clearing page table entries

pte_clear() et al are based on two paravirt steps today: one step to
create a page table entry with all zeroes, and one step to write this
entry value.

Drop the first step as it is completely useless.

Signed-off-by: Juergen Gross <jgross@...e.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20200815100641.26362-7-jgross@suse.com
---
 arch/x86/include/asm/paravirt.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index f0464b8..d25cc68 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -448,7 +448,7 @@ static inline pudval_t pud_val(pud_t pud)
 
 static inline void pud_clear(pud_t *pudp)
 {
-	set_pud(pudp, __pud(0));
+	set_pud(pudp, native_make_pud(0));
 }
 
 static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)
@@ -485,15 +485,15 @@ static inline void __set_pgd(pgd_t *pgdp, pgd_t pgd)
 } while (0)
 
 #define pgd_clear(pgdp) do {						\
-	if (pgtable_l5_enabled())						\
-		set_pgd(pgdp, __pgd(0));				\
+	if (pgtable_l5_enabled())					\
+		set_pgd(pgdp, native_make_pgd(0));			\
 } while (0)
 
 #endif  /* CONFIG_PGTABLE_LEVELS == 5 */
 
 static inline void p4d_clear(p4d_t *p4dp)
 {
-	set_p4d(p4dp, __p4d(0));
+	set_p4d(p4dp, native_make_p4d(0));
 }
 
 static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
@@ -504,12 +504,12 @@ static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
 static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
 			     pte_t *ptep)
 {
-	set_pte(ptep, __pte(0));
+	set_pte(ptep, native_make_pte(0));
 }
 
 static inline void pmd_clear(pmd_t *pmdp)
 {
-	set_pmd(pmdp, __pmd(0));
+	set_pmd(pmdp, native_make_pmd(0));
 }
 
 #define  __HAVE_ARCH_START_CONTEXT_SWITCH