Re: [PATCH 2/7] xen/gntdev,x86: Remove apply_to_page_range() use from module

From: Juergen Gross
Date: Mon Apr 12 2021 - 05:45:24 EST


On 12.04.21 10:26, Christoph Hellwig wrote:
On Mon, Apr 12, 2021 at 10:00:14AM +0200, Peter Zijlstra wrote:
Instead of relying on apply_to_page_range() being available to
modules, move its use into core kernel code and export it's
application.

This doesn't exactly look great, but at least it contains the damage..


NOTE: ideally we do: use_ptemod = !auto_translate_physmap &&
gnttab_map_avail_bits and remove this hack.

Given how much pain the !auto_translate_physmap case causes all over
the kernel I wonder what a realistic timeline might be for dropping
support for this case might be..

Think in the order of years.

It is basically the Xen PV guest support you are speaking of here, and
the planned replacement PVH especially for dom0 is still lacking some
functionality and it has performance issues.


Juergen

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