Re: [PATCH v5 1/6] docs/arm: Document Xen booting protocol on Armv8-R

[Julien Grall <julien@xxxxxxx>]

Hi Luca,

On 13/05/2025 09:45, Luca Fancellu wrote:
> Document the requirement needed to boot Xen on Armv8-R platforms.
>
> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
> Reviewed-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
> Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
> ---> v5 changes:
>   - restructured and removed some EL3 reference that might not
>     be there on Armv8-R aarch64
>   - add R-by Ayan and Michal
> v4 changes:
>   - New patch
> ---
>   docs/misc/arm/booting.txt | 11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/docs/misc/arm/booting.txt b/docs/misc/arm/booting.txt
> index 21ae74837dcc..ca05274392be 100644
> --- a/docs/misc/arm/booting.txt
> +++ b/docs/misc/arm/booting.txt
> @@ -56,12 +56,17 @@ image header to determine the load address, entry point, 
> etc.
>   Firmware/bootloader requirements
>   --------------------------------
>   
> -Xen relies on some settings the firmware has to configure in EL3 before starting Xen.
> +Xen relies on some settings the firmware has to configure before starting Xen.
>   
> -* Xen must be entered in NS EL2 mode
> +* Xen must be entered in:
> +  * Non-Secure EL2 mode for Armv8-A Arm64 and Arm32, Armv8-R Arm32.
> +  * Secure EL2 mode for Armv8-R Arm64.
>   
> -* The bit SCR_EL3.HCE (resp. SCR.HCE for 32-bit ARM) must be set to 1.
> +* When EL3 is supported, the bit SCR_EL3.HCE (resp. SCR.HCE for 32-bit ARM) 
> must
> +  be set to 1.
>   
> +* Xen must be entered with MMU/MPU off and data cache disabled (SCTLR_EL2.M bit
> +  and SCTLR_EL2.C set to 0).
The document read much better. Thanks for the update:

Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall