[PATCH 4.11 72/84] x86/mm: Fix flush_tlb_page() on Xen

Greg Kroah-Hartman
2017-07-03T13:35:52Z

From: Andy Lutomirski <luto@kernel.org>

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 <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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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
@@ -263,8 +263,6 @@ 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;
@@ -393,7 +391,7 @@ 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();
}