linux-kernel - Re: [PATCH v2 3/3] x86/mm: Fix flush_tlb

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Date:   Fri, 21 Apr 2017 14:46:32 -0400
From:   Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:     Andy Lutomirski <luto@...nel.org>, x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, Borislav Petkov <bp@...en8.de>,
        Rik van Riel <riel@...hat.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Nadav Amit <namit@...are.com>, Michal Hocko <mhocko@...e.com>,
        Sasha Levin <sasha.levin@...cle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Juergen Gross <jgross@...e.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: Re: [PATCH v2 3/3] x86/mm: Fix flush_tlb_page() on Xen

On 04/21/2017 02:15 PM, Andy Lutomirski wrote:
> 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.
>
> Cc: Rik van Riel <riel@...hat.com>
> Cc: Dave Hansen <dave.hansen@...el.com>
> Cc: Nadav Amit <namit@...are.com>
> Cc: Michal Hocko <mhocko@...e.com>
> Cc: Sasha Levin <sasha.levin@...cle.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
> Cc: Juergen Gross <jgross@...e.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Fixes: e7b52ffd45a6 ("x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range")
> Signed-off-by: Andy Lutomirski <luto@...nel.org>
> ---
>  arch/x86/mm/tlb.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

Thanks, Andy.

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>