Re: [PATCH] x86/HVM: tidy _hvm_load_entry() for style

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 31/07/2023 2:31 pm, Jan Beulich wrote:
> The primary goal is to eliminate the Misra-non-compliance of "desc"
> shadowing at least the local variable in hvm_load(). Suffix both local
> variables with underscores, while also
> - dropping leading underscores from parameter names (applying this also
>   to the two wrapper macros),
> - correcting indentation,
> - correcting brace placement,
> - dropping unnecessary parentheses around parameter uses when those are
>   passed on as plain arguments.
>
> No functional change intended.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/x86/include/asm/hvm/save.h
> +++ b/xen/arch/x86/include/asm/hvm/save.h
> @@ -47,30 +47,32 @@ void _hvm_read_entry(struct hvm_domain_c
>   * Unmarshalling: check, then copy. Evaluates to zero on success. This load
>   * function requires the save entry to be the same size as the dest 
> structure.
>   */
> -#define _hvm_load_entry(_x, _h, _dst, _strict) ({                       \
> -    int r;                                                              \
> -    struct hvm_save_descriptor *desc                                    \
> -        = (struct hvm_save_descriptor *)&(_h)->data[(_h)->cur];         \
> -    if ( (r = _hvm_check_entry((_h), HVM_SAVE_CODE(_x),                 \
> -               HVM_SAVE_LENGTH(_x), (_strict))) == 0 )                  \
> +#define _hvm_load_entry(x, h, dst, strict) ({                           \
> +    int r_;                                                             \
> +    struct hvm_save_descriptor *desc_                                   \
> +        = (struct hvm_save_descriptor *)&(h)->data[(h)->cur];           \
> +    if ( (r_ = _hvm_check_entry(h, HVM_SAVE_CODE(x),                    \
> +                                HVM_SAVE_LENGTH(x), strict)) == 0 )     \
>      {                                                                   \
> -        _hvm_read_entry((_h), (_dst), HVM_SAVE_LENGTH(_x));             \
> -        if ( HVM_SAVE_HAS_COMPAT(_x) &&                                 \
> -             desc->length != HVM_SAVE_LENGTH(_x) )                      \
> -            r = HVM_SAVE_FIX_COMPAT(_x, (_dst), desc->length);          \
> +        _hvm_read_entry(h, dst, HVM_SAVE_LENGTH(x));                    \
> +        if ( HVM_SAVE_HAS_COMPAT(x) &&                                  \
> +             desc_->length != HVM_SAVE_LENGTH(x) )                      \
> +            r_ = HVM_SAVE_FIX_COMPAT(x, dst, desc_->length);            \
>      }                                                                   \
> -    else if (HVM_SAVE_HAS_COMPAT(_x)                                    \
> -             && (r = _hvm_check_entry((_h), HVM_SAVE_CODE(_x),          \
> -                       HVM_SAVE_LENGTH_COMPAT(_x), (_strict))) == 0 ) { \
> -        _hvm_read_entry((_h), (_dst), HVM_SAVE_LENGTH_COMPAT(_x));      \
> -        r = HVM_SAVE_FIX_COMPAT(_x, (_dst), desc->length);              \
> +    else if (HVM_SAVE_HAS_COMPAT(x)                                     \
> +             && (r_ = _hvm_check_entry(h, HVM_SAVE_CODE(x),             \

&& on prev line, and an extra space before HVM_SAVE_HAS_COMPAT()

With that, Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

This code re-enforces my firm belief that this has no business living in
the hypervisor at all.  All of this can live in userspace, with a
slightly improved hypercall interface.

~Andrew