Re: [PATCH v2 6/6] aarch64: Start Xen on Armv8-R at EL2

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

On Tue, Jul 16, 2024 at 03:29:06PM +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.
> 
> Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>

Just to check, this requires using spin-table, right?

I don't expect there to be interworking between the boot-wrapper and
Xen.

Mark.

> ---
> v2 changes:
>  - Don't write 1 on flag_keep_el since now the logic will jump to
>    reset_no_el3 and write it there.
>  - removed check for smc conduit when Xen is booted, change commit
>    message.
> ---
>  Makefile.am         | 1 +
>  arch/aarch64/boot.S | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/Makefile.am b/Makefile.am
> index 34fbfb1f4ff8..bafce34682c3 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -112,6 +112,7 @@ 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 2a8234f7a17d..38ed4ed48985 100644
> --- a/arch/aarch64/boot.S
> +++ b/arch/aarch64/boot.S
> @@ -88,6 +88,7 @@ reset_at_el2:
>  	cmp	x0, 0xf
>  	bne	reset_no_el3
>  
> +#if !defined(XEN)
>  	/*
>  	 * Armv8-R AArch64 is found, check if Linux can be booted.
>  	 * Check MSA_frac, bits [55:52]:
> @@ -107,6 +108,7 @@ reset_at_el2:
>  	mov	w0, #SPSR_KERNEL_EL1
>  	ldr	x1, =spsr_to_elx
>  	str	w0, [x1]
> +#endif
>  
>  	bl	cpu_init_armv8r_el2
>  
> -- 
> 2.34.1
>