Re: [PATCH] xen: Add versions of rcu_lock_*_domain without IS_PRIV

[Keir Fraser <keir@xen.org>]

Must we have two new calls for translating a domid to a domain? It's getting
to be a confusing mess isn't it? Also, here, a more consistent name for
rcu_lock_domain_by_any_id would be rcu_lock_any_domain_by_id, I think?

 -- Keir


On 15/10/2012 15:02, "Daniel De Graaf" <dgdegra@tycho.nsa.gov> wrote:

> While this patch is a part of my XSM IS_PRIV series, I am reposting it
> alone because the XSM build of xen-unstable is currently broken. I can
> also repost the remaining patches series if that would be helpful.
> 
> --------------------------------->8----------------------------------
> 
> These functions will be used to avoid duplication of IS_PRIV calls
> that will be introduced in XSM hooks. This also fixes a build error
> with XSM enabled introduced by 25925:d1c3375c3f11 which depends on
> this patch.
> 
> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
> ---
>  xen/common/domain.c     | 21 +++++++++++++++++++++
>  xen/include/xen/sched.h | 11 +++++++++++
>  2 files changed, 32 insertions(+)
> 
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index a1aa05e..52489b3 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -420,6 +420,13 @@ struct domain *rcu_lock_domain_by_id(domid_t dom)
>      return d;
>  }
>  
> +struct domain *rcu_lock_domain_by_any_id(domid_t dom)
> +{
> +    if ( dom == DOMID_SELF )
> +        return rcu_lock_current_domain();
> +    return rcu_lock_domain_by_id(dom);
> +}
> +
>  int rcu_lock_target_domain_by_id(domid_t dom, struct domain **d)
>  {
>      if ( dom == DOMID_SELF )
> @@ -454,6 +461,20 @@ int rcu_lock_remote_target_domain_by_id(domid_t dom,
> struct domain **d)
>      return 0;
>  }
>  
> +int rcu_lock_remote_domain_by_id(domid_t dom, struct domain **d)
> +{
> +    if ( (*d = rcu_lock_domain_by_id(dom)) == NULL )
> +        return -ESRCH;
> +
> +    if ( *d == current->domain )
> +    {
> +        rcu_unlock_domain(*d);
> +        return -EPERM;
> +    }
> +
> +    return 0;
> +}
> +
>  int domain_kill(struct domain *d)
>  {
>      int rc = 0;
> diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
> index 53804c8..b0def4a 100644
> --- a/xen/include/xen/sched.h
> +++ b/xen/include/xen/sched.h
> @@ -447,6 +447,11 @@ struct domain *domain_create(
>  struct domain *rcu_lock_domain_by_id(domid_t dom);
>  
>  /*
> + * As above function, but resolves DOMID_SELF to current domain
> + */
> +struct domain *rcu_lock_domain_by_any_id(domid_t dom);
> +
> +/*
>   * As above function, but accounts for current domain context:
>   *  - Translates target DOMID_SELF into caller's domain id; and
>   *  - Checks that caller has permission to act on the target domain.
> @@ -460,6 +465,12 @@ int rcu_lock_target_domain_by_id(domid_t dom, struct
> domain **d);
>   */
>  int rcu_lock_remote_target_domain_by_id(domid_t dom, struct domain **d);
>  
> +/*
> + * As rcu_lock_domain_by_id(), but will fail EPERM or ESRCH rather than
> resolve
> + * to local domain.
> + */
> +int rcu_lock_remote_domain_by_id(domid_t dom, struct domain **d);
> +
>  /* Finish a RCU critical region started by rcu_lock_domain_by_id(). */
>  static inline void rcu_unlock_domain(struct domain *d)
>  {