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

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

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>

--
Sincerely,
Andrii Anisov.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel