Re: [PATCH 2/2] arm/xen: Add misuse warning to virt_to_gfn

[Jan Beulich <jbeulich@xxxxxxxx>]

On 25.08.2020 11:31, Simon Leiner wrote:
> --- a/include/xen/arm/page.h
> +++ b/include/xen/arm/page.h
> @@ -76,7 +76,11 @@ static inline unsigned long bfn_to_pfn(unsigned long bfn)
>  #define bfn_to_local_pfn(bfn)        bfn_to_pfn(bfn)
>  
>  /* VIRT <-> GUEST conversion */
> -#define virt_to_gfn(v)               (pfn_to_gfn(virt_to_phys(v) >> 
> XEN_PAGE_SHIFT))
> +#define virt_to_gfn(v)                                                       
>   \
> +     ({                                                                     \
> +             WARN_ON_ONCE(is_vmalloc_addr(v));                              \
> +             pfn_to_gfn(virt_to_phys(v) >> XEN_PAGE_SHIFT);                 \
> +     })

Shouldn't such a check cover more than just the vmalloc range,
i.e. everything outside of what __va() can validly return?

Jan