Re: [XEN PATCH v2 2/4] x86/mtrr: address MISRA C:2012 Rule 5.3

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 4 Aug 2023, Nicola Vetrini wrote:
> Rename variables to avoid shadowing and thus address
> MISRA C:2012 Rule 5.3:
> "An identifier declared in an inner scope shall not hide an
> identifier declared in an outer scope".
> 
> The shadowing happens between the struct declaration 'mtrr_state' in
> 'xen/arch/x86/include/asm/mtrr.h' and local variable names.
> The latter are renamed to 'm', which is used elsewhere in
> 'xen/arch/x86/hvm/mtrr.c' for the same purpose.
> 
> No functional changes.
> 
> Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> Changes in v2:
> - Renamed 'mtrr' local variables to 'm'.
> - Added references in the commit message.
> ---
>  xen/arch/x86/hvm/mtrr.c | 32 ++++++++++++++++----------------
>  1 file changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c
> index 29f3fb1607..7f486358b1 100644
> --- a/xen/arch/x86/hvm/mtrr.c
> +++ b/xen/arch/x86/hvm/mtrr.c
> @@ -687,13 +687,13 @@ int hvm_set_mem_pinned_cacheattr(struct domain *d, 
> uint64_t gfn_start,
> 
>  static int cf_check hvm_save_mtrr_msr(struct vcpu *v, hvm_domain_context_t 
> *h)
>  {
> -    const struct mtrr_state *mtrr_state = &v->arch.hvm.mtrr;
> +    const struct mtrr_state *m = &v->arch.hvm.mtrr;
>      struct hvm_hw_mtrr hw_mtrr = {
> -        .msr_mtrr_def_type = mtrr_state->def_type |
> -                             MASK_INSR(mtrr_state->fixed_enabled,
> +        .msr_mtrr_def_type = m->def_type |
> +                             MASK_INSR(m->fixed_enabled,
>                                         MTRRdefType_FE) |
> -                            MASK_INSR(mtrr_state->enabled, MTRRdefType_E),
> -        .msr_mtrr_cap      = mtrr_state->mtrr_cap,
> +                            MASK_INSR(m->enabled, MTRRdefType_E),
> +        .msr_mtrr_cap      = m->mtrr_cap,
>      };
>      unsigned int i;
> 
> @@ -710,14 +710,14 @@ static int cf_check hvm_save_mtrr_msr(struct vcpu *v, 
> hvm_domain_context_t *h)
> 
>      for ( i = 0; i < MASK_EXTR(hw_mtrr.msr_mtrr_cap, MTRRcap_VCNT); i++ )
>      {
> -        hw_mtrr.msr_mtrr_var[i * 2] = mtrr_state->var_ranges->base;
> -        hw_mtrr.msr_mtrr_var[i * 2 + 1] = mtrr_state->var_ranges->mask;
> +        hw_mtrr.msr_mtrr_var[i * 2] = m->var_ranges->base;
> +        hw_mtrr.msr_mtrr_var[i * 2 + 1] = m->var_ranges->mask;
>      }
> 
>      BUILD_BUG_ON(sizeof(hw_mtrr.msr_mtrr_fixed) !=
> -                 sizeof(mtrr_state->fixed_ranges));
> +                 sizeof(m->fixed_ranges));
> 
> -    memcpy(hw_mtrr.msr_mtrr_fixed, mtrr_state->fixed_ranges,
> +    memcpy(hw_mtrr.msr_mtrr_fixed, m->fixed_ranges,
>             sizeof(hw_mtrr.msr_mtrr_fixed));
> 
>      return hvm_save_entry(MTRR, v->vcpu_id, h, &hw_mtrr);
> @@ -727,7 +727,7 @@ static int cf_check hvm_load_mtrr_msr(struct domain *d, 
> hvm_domain_context_t *h)
>  {
>      unsigned int vcpuid, i;
>      struct vcpu *v;
> -    struct mtrr_state *mtrr_state;
> +    struct mtrr_state *m;
>      struct hvm_hw_mtrr hw_mtrr;
> 
>      vcpuid = hvm_load_instance(h);
> @@ -749,26 +749,26 @@ static int cf_check hvm_load_mtrr_msr(struct domain *d, 
> hvm_domain_context_t *h)
>          return -EINVAL;
>      }
> 
> -    mtrr_state = &v->arch.hvm.mtrr;
> +    m = &v->arch.hvm.mtrr;
> 
>      hvm_set_guest_pat(v, hw_mtrr.msr_pat_cr);
> 
> -    mtrr_state->mtrr_cap = hw_mtrr.msr_mtrr_cap;
> +    m->mtrr_cap = hw_mtrr.msr_mtrr_cap;
> 
>      for ( i = 0; i < NUM_FIXED_MSR; i++ )
> -        mtrr_fix_range_msr_set(d, mtrr_state, i, hw_mtrr.msr_mtrr_fixed[i]);
> +        mtrr_fix_range_msr_set(d, m, i, hw_mtrr.msr_mtrr_fixed[i]);
> 
>      for ( i = 0; i < MASK_EXTR(hw_mtrr.msr_mtrr_cap, MTRRcap_VCNT); i++ )
>      {
> -        mtrr_var_range_msr_set(d, mtrr_state,
> +        mtrr_var_range_msr_set(d, m,
>                                 MSR_IA32_MTRR_PHYSBASE(i),
>                                 hw_mtrr.msr_mtrr_var[i * 2]);
> -        mtrr_var_range_msr_set(d, mtrr_state,
> +        mtrr_var_range_msr_set(d, m,
>                                 MSR_IA32_MTRR_PHYSMASK(i),
>                                 hw_mtrr.msr_mtrr_var[i * 2 + 1]);
>      }
> 
> -    mtrr_def_type_msr_set(d, mtrr_state, hw_mtrr.msr_mtrr_def_type);
> +    mtrr_def_type_msr_set(d, m, hw_mtrr.msr_mtrr_def_type);
> 
>      return 0;
>  }
> --
> 2.34.1
>