Re: [boot-wrapper v3 4/4] aarch64: Start Xen on Armv8-R at EL2

[Mark Rutland <mark.rutland@arm.com>]

On Wed, Jul 31, 2024 at 03:11:03PM +0100, Luca Fancellu wrote:
> When bootwrapper is compiled with Xen support and it is started
> at EL2 on Armv8-R AArch64, keep the current EL and jump to the
> Xen image using the SPSR_KERNEL as spsr_el2 value.
> 
> Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
> ---
> Changes from v2:
>  - Major rework, reason in the cover letter.
> ---
>  Makefile.am         | 1 +
>  arch/aarch64/boot.S | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/Makefile.am b/Makefile.am
> index 62e2988c0dd3..0aee117eb827 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -113,6 +113,7 @@ XEN_CHOSEN	:= xen,xen-bootargs = \"$(XEN_CMDLINE)\";		\
>  			compatible = \"xen,linux-zimage\", \"xen,multiboot-module\"; \
>  			reg = <0x0 $(DOM0_OFFSET) 0x0 $(KERNEL_SIZE)>;	\
>  		   };
> +DEFINES		+= -DXEN
>  endif
>  
>  if INITRD
> diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
> index 0b4f6824045a..d50ff48d83de 100644
> --- a/arch/aarch64/boot.S
> +++ b/arch/aarch64/boot.S
> @@ -100,7 +100,7 @@ ASM_FUNC(jump_kernel)
>  	mov	x1, x21
>  	mov	x2, x22
>  	mov	x3, x23
> -#if defined(BOOTWRAPPER_64R)
> +#if defined(BOOTWRAPPER_64R) && !defined(XEN)
>  	// On Armv8-R Linux needs to be booted at EL1
>  	mov	x4, #SPSR_KERNEL_EL1
>  #else

FWIW, this looks fine to me.

Mark.