Re: [PATCH v3 6/7] xsm: drop generic event channel labeling exclusion

["Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>]

On 8/25/21 11:44 AM, Jan Beulich wrote:
> On 05.08.2021 16:06, Daniel P. Smith wrote:
>> The internal define flag is not used by any XSM module, removing the #ifdef
>> leaving the generic event channel labeling as always present.
> 
> With this description ...
> 
>> --- a/xen/include/xen/sched.h
>> +++ b/xen/include/xen/sched.h
>> @@ -120,15 +120,12 @@ struct evtchn
>>      unsigned short notify_vcpu_id; /* VCPU for local delivery notification 
>> */
>>      uint32_t fifo_lastq;           /* Data for identifying last queue. */
>>  
>> -#ifdef CONFIG_XSM
>>      union {
>> -#ifdef XSM_NEED_GENERIC_EVTCHN_SSID
>>          /*
>>           * If an XSM module needs more space for its event channel context,
>>           * this pointer stores the necessary data for the security server.
>>           */
>>          void *generic;
>> -#endif
>>  #ifdef CONFIG_XSM_FLASK
>>          /*
>>           * Inlining the contents of the structure for FLASK avoids unneeded
>> @@ -138,7 +135,6 @@ struct evtchn
>>          uint32_t flask_sid;
>>  #endif
>>      } ssid;
>> -#endif
>>  } __attribute__((aligned(64)));
> 
> ... I can see the inner #ifdef go away, but not the outer one. While
> the (imo bogus) attribute means you don't alter the size of the
> struct, I'm afraid that's not obvious at all without counting bits
> and bytes, and hence this may also want saying explicitly in the
> description.

I can put the #ifdef CONFIG_XSM back and in the subsequent patch change
it to CONFIG_XSM_CONFIGURABLE, making this the only difference between
being able to select the XSM policy in effect or not.

v/r,
dps