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@kernel.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.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@kernel.org>

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 9db9260a5e9fcf78cd7ffa33a6f393e187cf4401..6e7bedf69af78d4fd9fec1f4144542b91ce5892b 100644 (file)
--- 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();
 }