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Re: [Xen-devel] [PATCH for-4.12 v2 2/2] xen/arm: Stop relocating Xen

On 14.12.18 13:44, Julien Grall wrote:
At the moment, Xen is relocated towards the end of the memory. While
this has the advantage to free space in low memory, the code is not
compliant with the break-before-make because it requires to switch
between two sets of page-table. This is not entirely trivial to fix as
it would require us to go through an identity mapping and disabling MMU.

Furthermore, it looks like that some platform (such as the Hikey960)
may not be able to bring-up secondary CPUs if the entry is too high.

I don't believe the low memory is an issue because Xen is quite tiny
(< 2MB). So the best solution is to stop relocating Xen. This has the
advantage to simplify the code and should speed-up the boot as relocation
is not necessary anymore.

Note that the break-before-make issue is not fixed by this patch.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reported-by: Matthew Daley <mattd@xxxxxxxxxxx>
Tested-by: Matthew Daley <mattd@xxxxxxxxxxx>

Tested-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
Reviewed-by: Andrii Anisov <andrii_anisov@xxxxxxxx>

Andrii Anisov.

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