Re: [Xen-devel] [PATCH 2/7] xen/arm: Remove flush_xen_text_tlb_local()

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

On 25.04.19 23:37, Julien Grall wrote:
> The understanding is correct. I am not entirely sure how I can improve
> the comment.
I've re-read the comment again, and realized it actually fits. So let it be.

> To be honest, I am not entirely sure whether the isb() is necessary
> here. At worst, an entry of an existing mappings is not cached with the
> SCTLR_EL2.WXN set. This may only defer the problem is an entry is
> incorrectly configured before the flush. This is done early at boot (and
> will be done much earlier in [1]).Well, following this logic we may finish with 
> TLB flush is not needed here at all. Because entries, already reached TLB, were 
> configured before, and are believed valid. All the next will have WXN set.
But in this case, ISB is needed as an exact point from which all new TLB 
entries will have WXN.

> So I am kind of tempted to drop the
> isb() here.
--
Sincerely,
Andrii Anisov.

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