Re: [PATCH 3/5] x86/shadow: conditionalize / rename local variables

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Wed, May 13, 2026 at 01:45:12PM +0200, Jan Beulich wrote:
> ... shadowing a function scope one in one case and the global _end[] in
> another, thus violating Misra C:2012 rule 5.3 ("An identifier declared in
> an inner scope shall not hide an identifier declared in an outer scope").
> No difference in generated code.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

> 
> --- a/xen/arch/x86/mm/shadow/multi.c
> +++ b/xen/arch/x86/mm/shadow/multi.c
> @@ -857,13 +857,13 @@ do {
>  /* 64-bit l2: touch all entries except for PAE compat guests. */
>  #define FOREACH_PRESENT_L2E(_sl2mfn, _sl2e, _gl2p, _done, _dom, _code)      \
>  do {                                                                        \
> -    unsigned int _i, _end = SHADOW_L2_PAGETABLE_ENTRIES;                    \
> +    unsigned int _i, _nr = SHADOW_L2_PAGETABLE_ENTRIES;                     \
>      shadow_l2e_t *_sp = map_domain_page((_sl2mfn));                         \
>      ASSERT_VALID_L2(mfn_to_page(_sl2mfn)->u.sh.type);                       \
>      if ( is_pv_32bit_domain(_dom) /* implies !paging_mode_external */ &&    \
>           mfn_to_page(_sl2mfn)->u.sh.type != SH_type_l2_64_shadow )          \
> -        _end = COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(_dom);                    \
> -    for ( _i = 0; _i < _end; ++_i )                                         \
> +        _nr = COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(_dom);                     \
> +    for ( _i = 0; _i < _nr; ++_i )                                          \
>      {                                                                       \
>          (_sl2e) = _sp + _i;                                                 \
>          if ( shadow_l2e_get_flags(*(_sl2e)) & _PAGE_PRESENT )               \
> @@ -3349,7 +3349,9 @@ static pagetable_t cf_check sh_update_cr
>  #if SHADOW_PAGING_LEVELS == 3
>          {
>              mfn_t smfn = 
> pagetable_get_mfn(v->arch.paging.shadow.shadow_table[0]);
> +#if GUEST_PAGING_LEVELS != 3
>              unsigned int i;
> +#endif

Hm, that one is nasty, we would better use a different variable name,
but that would be more churn.

Thanks, Roger.