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

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

On 10/15/2012 11:26 AM, Keir Fraser wrote:
> 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

The original version of this patch queue removed the two _target_ calls;
that removal is not in the current versions to avoid breaking code that is
not yet converted (ARM and two other callers not converted).

The name rcu_lock_any_domain_by_id is also fine, although it seems to imply
that rcu_lock_domain_by_id cannot lock any domain, when the real difference
is if they accept DOMID_SELF (hence why I chose to say any_id). Would you
like me to send a patch changing the name?
 
> 
> On 15/10/2012 15:02, "Daniel De Graaf" <dgdegra@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
>> ---
>>  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)
>>  {
> 


-- 
Daniel De Graaf
National Security Agency

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