linux-kernel - [PATCH 5/8] x86/mm/cpa: Move CLFLUSH test into cpa_flush

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Date:   Wed, 19 Sep 2018 10:50:21 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Bin Yang <bin.yang@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Mark Gross <mark.gross@...el.com>
Subject: [PATCH 5/8] x86/mm/cpa: Move CLFLUSH test into cpa_flush_range()

Rather than guarding all cpa_flush_range() uses with a CLFLUSH test,
put it inside.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/mm/pageattr.c |   15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -293,6 +293,11 @@ static void cpa_flush_range(unsigned lon
 	BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
 	WARN_ON(PAGE_ALIGN(start) != start);
 
+	if (!static_cpu_has(X86_FEATURE_CLFLUSH)) {
+		cpa_flush_all(cache);
+		return;
+	}
+
 	flush_tlb_kernel_range(start, start + PAGE_SIZE * numpages);
 
 	if (!cache)
@@ -2075,10 +2080,7 @@ static int __set_memory_enc_dec(unsigned
 	/*
 	 * Before changing the encryption attribute, we need to flush caches.
 	 */
-	if (static_cpu_has(X86_FEATURE_CLFLUSH))
-		cpa_flush_range(start, numpages, 1);
-	else
-		cpa_flush_all(1);
+	cpa_flush_range(start, numpages, 1);
 
 	ret = __change_page_attr_set_clr(&cpa, 1);
 
@@ -2089,10 +2091,7 @@ static int __set_memory_enc_dec(unsigned
 	 * in case TLB flushing gets optimized in the cpa_flush_range()
 	 * path use the same logic as above.
 	 */
-	if (static_cpu_has(X86_FEATURE_CLFLUSH))
-		cpa_flush_range(start, numpages, 0);
-	else
-		cpa_flush_all(0);
+	cpa_flush_range(start, numpages, 0);
 
 	return ret;
 }