Re: [XEN v3 7/9] xen/arm: guest_walk: LPAE specific bits should be enclosed within "ifndef CONFIG_ARM_PA_32"

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 8 Feb 2023, Ayan Kumar Halder wrote:
> In the subsequent patch, we introduce "CONFIG_ARM_PA_32" to support
> 32 bit physical addresses. Thus, the code specific to
> "Large Physical Address Extension" (ie LPAE) should be enclosed within
> "ifndef CONFIG_ARM_PA_32".

this statement needs an  update


> Refer xen/arch/arm/include/asm/short-desc.h, "short_desc_l1_supersec_t"
> unsigned int extbase1:4;    /* Extended base address, PA[35:32] */
> unsigned int extbase2:4;    /* Extended base address, PA[39:36] */
> 
> Thus, extbase1 and extbase2 are not valid when 32 bit physical addresses
> are supported.
> 
> Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>

Aside from the above:

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> 
> Changes from -
> v1 - 1. Extracted from "[XEN v1 8/9] xen/arm: Other adaptations required to 
> support 32bit paddr".
> 
> v2 - 1. Reordered this patch so that it appears after CONFIG_ARM_PA_32 is
> introduced (in 6/9).
> 
>  xen/arch/arm/guest_walk.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/xen/arch/arm/guest_walk.c b/xen/arch/arm/guest_walk.c
> index 43d3215304..0feb7b76ec 100644
> --- a/xen/arch/arm/guest_walk.c
> +++ b/xen/arch/arm/guest_walk.c
> @@ -154,8 +154,10 @@ static bool guest_walk_sd(const struct vcpu *v,
>              mask = (1ULL << L1DESC_SUPERSECTION_SHIFT) - 1;
>              *ipa = gva & mask;
>              *ipa |= (paddr_t)(pte.supersec.base) << 
> L1DESC_SUPERSECTION_SHIFT;
> +#ifndef CONFIG_ARM_PA_32
>              *ipa |= (paddr_t)(pte.supersec.extbase1) << 
> L1DESC_SUPERSECTION_EXT_BASE1_SHIFT;
>              *ipa |= (paddr_t)(pte.supersec.extbase2) << 
> L1DESC_SUPERSECTION_EXT_BASE2_SHIFT;
> +#endif /* CONFIG_ARM_PA_32 */
>          }
>  
>          /* Set permissions so that the caller can check the flags by 
> herself. */
> -- 
> 2.17.1
> 
>