Re: [Xen-devel] [XEN VMID PATCH 2/2 v3] xen/arm: Add support for 16 bit VMIDs

[Julien Grall <julien.grall@xxxxxxx>]

Hi Bhupinder,

On 12/12/16 07:26, Bhupinder Thakur wrote:

[...]

> -void p2m_vmid_allocator_init(void)
> +int p2m_vmid_allocator_init(void)
>  {
> -    set_bit(INVALID_VMID, vmid_mask);
> +    int ret = 0;
> +
> +    /*
> +     * allocate space for vmid_mask based on MAX_VMID
> +     */
> +    vmid_mask = xzalloc_array(unsigned long, BITS_TO_LONGS(MAX_VMID));
I would directly handle the panic within this function rather than 
return an error. I.e
if ( !vmid_mask )
  panic(....);

This would simplify the logic a bit.

> +
> +    if ( vmid_mask )
> +        set_bit(INVALID_VMID, vmid_mask);
> +    else
> +        ret = -1;
> +
> +    return ret;
>  }
>
>  static int p2m_alloc_vmid(struct domain *d)
> @@ -1632,20 +1653,36 @@ void __init setup_virt_paging(void)
>
>      unsigned int cpu;
>      unsigned int pa_range = 0x10; /* Larger than any possible value */
> +    unsigned int vmid_8_bit_flag = 0;
Please use bool:

bool vmid_8_bit_flag = false;

I would also drop _flag as it is not necessary.

>      for_each_online_cpu ( cpu )
>      {
>          const struct cpuinfo_arm *info = &cpu_data[cpu];
>          if ( info->mm64.pa_range < pa_range )
>              pa_range = info->mm64.pa_range;
> +
> +        /* set a flag if the current cpu does not suppot 16 bit VMIDs */
> +        if ( info->mm64.vmid_bits != MM64_VMID_16_BITS_SUPPORT )
> +            vmid_8_bit_flag = 1;
s/1/true/

The rest of the patch looks good to me.

Cheers,

--
Julien Grall

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