Re: [Xen-devel] [PATCH v3 16/38] arm/p2m: Add HVMOP_altp2m_set_domain_state

[Julien Grall <julien.grall@xxxxxxx>]

Hello Sergej,

On 16/08/16 23:16, Sergej Proskurin wrote:
> +static int altp2m_init_helper(struct domain *d, unsigned int idx)
> +{
> +    int rc;
> +    struct p2m_domain *p2m = d->arch.altp2m_p2m[idx];
> +
> +    ASSERT(p2m == NULL);
> +
> +    /* Allocate a new, zeroed altp2m view. */
> +    p2m = xzalloc(struct p2m_domain);
> +    if ( p2m == NULL)
> +    {
> +        rc = -ENOMEM;
> +        goto err;
> +    }
This could be simplified with just return -ENOMEM.

> +
> +    p2m->p2m_class = p2m_alternate;
> +
> +    /* Initialize the new altp2m view. */
> +    rc = p2m_init_one(d, p2m);
> +    if ( rc )
> +        goto err;
> +
> +    p2m->access_required = false;
> +    _atomic_set(&p2m->active_vcpus, 0);
the p2m is initialized to 0, so both access_required and active_vcpus 
initialization is not necessary.
> +
> +    d->arch.altp2m_p2m[idx] = p2m;
> +
> +    return rc;
> +
> +err:
> +    if ( p2m )
> +        xfree(p2m);
xfree is able to handle NULL pointer.

> +
> +    d->arch.altp2m_p2m[idx] = NULL;
> +
> +    return rc;
> +}
> +
> +int altp2m_init_by_id(struct domain *d, unsigned int idx)
> +{
> +    int rc = -EINVAL;
> +
> +    if ( idx >= MAX_ALTP2M )
> +        return rc;
> +
> +    altp2m_lock(d);
> +
> +    if ( d->arch.altp2m_p2m[idx] == NULL )
> +        rc = altp2m_init_helper(d, idx);
> +
> +    altp2m_unlock(d);
> +
> +    return rc;
> +}
> +
Regards,

--
Julien Grall

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