linux-kernel - [tip:x86/mm] x86/mm/cpa: Fix cpa_flush

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Message-ID: <tip-721066dfd4d5c0fee5772c777d6930d0f423b4eb@git.kernel.org>
Date:   Mon, 17 Dec 2018 10:20:38 -0800
From:   tip-bot for Peter Zijlstra <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     dave.hansen@...ux.intel.com, riel@...riel.com, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, peterz@...radead.org,
        torvalds@...ux-foundation.org, hpa@...or.com, Tom.StDenis@....com,
        bp@...en8.de, mingo@...nel.org, luto@...nel.org
Subject: [tip:x86/mm] x86/mm/cpa: Fix cpa_flush_array() TLB invalidation

Commit-ID:  721066dfd4d5c0fee5772c777d6930d0f423b4eb
Gitweb:     https://git.kernel.org/tip/721066dfd4d5c0fee5772c777d6930d0f423b4eb
Author:     Peter Zijlstra <peterz@...radead.org>
AuthorDate: Mon, 3 Dec 2018 18:03:44 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 17 Dec 2018 18:48:09 +0100

x86/mm/cpa: Fix cpa_flush_array() TLB invalidation

In commit:

  a7295fd53c39 ("x86/mm/cpa: Use flush_tlb_kernel_range()")

I misread the CAP array code and incorrectly used
tlb_flush_kernel_range(), resulting in missing TLB flushes and
consequent failures.

Instead do a full invalidate in this case -- for now.

Reported-by: StDenis, Tom <Tom.StDenis@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rik van Riel <riel@...riel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: dave.hansen@...el.com
Fixes: a7295fd53c39 ("x86/mm/cpa: Use flush_tlb_kernel_range()")
Link: http://lkml.kernel.org/r/20181203171043.089868285@infradead.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/mm/pageattr.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index db7a10082238..a1bcde35db4c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -285,20 +285,16 @@ static void cpa_flush_all(unsigned long cache)
 	on_each_cpu(__cpa_flush_all, (void *) cache, 1);
 }
 
-static bool __cpa_flush_range(unsigned long start, int numpages, int cache)
+static bool __inv_flush_all(int cache)
 {
 	BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
 
-	WARN_ON(PAGE_ALIGN(start) != start);
-
 	if (cache && !static_cpu_has(X86_FEATURE_CLFLUSH)) {
 		cpa_flush_all(cache);
 		return true;
 	}
 
-	flush_tlb_kernel_range(start, start + PAGE_SIZE * numpages);
-
-	return !cache;
+	return false;
 }
 
 static void cpa_flush_range(unsigned long start, int numpages, int cache)
@@ -306,7 +302,14 @@ static void cpa_flush_range(unsigned long start, int numpages, int cache)
 	unsigned int i, level;
 	unsigned long addr;
 
-	if (__cpa_flush_range(start, numpages, cache))
+	WARN_ON(PAGE_ALIGN(start) != start);
+
+	if (__inv_flush_all(cache))
+		return;
+
+	flush_tlb_kernel_range(start, start + PAGE_SIZE * numpages);
+
+	if (!cache)
 		return;
 
 	/*
@@ -332,7 +335,12 @@ static void cpa_flush_array(unsigned long baddr, unsigned long *start,
 {
 	unsigned int i, level;
 
-	if (__cpa_flush_range(baddr, numpages, cache))
+	if (__inv_flush_all(cache))
+		return;
+
+	flush_tlb_all();
+
+	if (!cache)
 		return;
 
 	/*