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Re: [Xen-devel] [PATCH for-4.12 v2 04/17] xen/arm: p2m: Introduce p2m_is_valid and use it

Hi Stefano,

On 04/12/2018 23:50, Stefano Stabellini wrote:
On Tue, 4 Dec 2018, Julien Grall wrote:
The LPAE format allows to store information in an entry even with the
valid bit unset. In a follow-up patch, we will take advantage of this
feature to re-purpose the valid bit for generating a translation fault
even if an entry contains valid information.

So we need a different way to know whether an entry contains valid
information. It is possible to use the information hold in the p2m_type
to know for that purpose. Indeed all entries containing valid
information will have a valid p2m type (i.e p2m_type != p2m_invalid).

This patch introduces a new helper p2m_is_valid, which implements that
idea, and replace most of lpae_is_valid call with the new helper. The ones
remaining are for TLBs handling and entries accounting.

With the renaming there are 2 others changes required:
     - Generate table entry with a valid p2m type
     - Detect new mapping for proper stats accounting

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

(This patch doesn't apply to master, please rebase)

Why are you trying to apply to master? This series (as most of my series) are based on staging at the time it was sent. I tried to apply this patch today on staging and I didn't find any issue.


Julien Grall

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