4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andy Lutomirski <[email protected]>

commit dbd68d8e84c606673ebbcf15862f8c155fa92326 upstream.

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 <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
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.l...@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/x86/mm/tlb.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -134,8 +134,6 @@ void native_flush_tlb_others(const struc
 {
        struct flush_tlb_info info;
 
-       if (end == 0)
-               end = start + PAGE_SIZE;
        info.flush_mm = mm;
        info.flush_start = start;
        info.flush_end = end;
@@ -264,7 +262,7 @@ void flush_tlb_page(struct vm_area_struc
        }
 
        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();
 }


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