linux-kernel - [tip:x86/mm] x86/mm: Fix flush_tlb

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Date:   Wed, 26 Apr 2017 01:28:04 -0700
From:   tip-bot for Andy Lutomirski <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, torvalds@...ux-foundation.org,
        konrad.wilk@...cle.com, riel@...hat.com, tglx@...utronix.de,
        luto@...nel.org, brgerst@...il.com, jpoimboe@...hat.com,
        peterz@...radead.org, namit@...are.com, mingo@...nel.org,
        boris.ostrovsky@...cle.com, linux-kernel@...r.kernel.org,
        dave.hansen@...el.com, jgross@...e.com, dvlasenk@...hat.com,
        akpm@...ux-foundation.org, bp@...en8.de, mhocko@...e.com
Subject: [tip:x86/mm] x86/mm: Fix flush_tlb_page() on Xen

Commit-ID:  dbd68d8e84c606673ebbcf15862f8c155fa92326
Gitweb:     http://git.kernel.org/tip/dbd68d8e84c606673ebbcf15862f8c155fa92326
Author:     Andy Lutomirski <luto@...nel.org>
AuthorDate: Sat, 22 Apr 2017 00:01:22 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 26 Apr 2017 10:02:06 +0200

x86/mm: Fix flush_tlb_page() on Xen

flush_tlb_page() passes a bogus range to flush_tlb_others() and
expects the latter to fix it up.  native_flush_tlb_others() has the
fixup but Xen's version doesn't.  Move the fixup to
flush_tlb_others().

AFAICS the only real effect is that, without this fix, Xen would
flush everything instead of just the one page on remote vCPUs in
when flush_tlb_page() was called.

Signed-off-by: Andy Lutomirski <luto@...nel.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Nadav Amit <namit@...are.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rik van Riel <riel@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Fixes: e7b52ffd45a6 ("x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range")
Link: http://lkml.kernel.org/r/10ed0e4dfea64daef10b87fb85df1746999b4dba.1492844372.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/mm/tlb.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 9db9260..6e7bedf 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -263,8 +263,6 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
 {
 	struct flush_tlb_info info;
 
-	if (end == 0)
-		end = start + PAGE_SIZE;
 	info.flush_mm = mm;
 	info.flush_start = start;
 	info.flush_end = end;
@@ -378,7 +376,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long start)
 	}
 
 	if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
-		flush_tlb_others(mm_cpumask(mm), mm, start, 0UL);
+		flush_tlb_others(mm_cpumask(mm), mm, start, start + PAGE_SIZE);
 
 	preempt_enable();
 }