xen: clean up altp2m op comment

Delete trailing spaces and refer to XSM instead of an internal
function in the public header.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/hvm/hvm.c

@@ -4468,16 +4468,16 @@ static int hvmop_get_param(
 }
 
 /*
- * altp2m operations are envisioned as being used in several different 
+ * altp2m operations are envisioned as being used in several different
  * modes:
- * 
+ *
  * - external: All control and decisions are made by an external agent
  *   running domain 0.
  *
  * - internal: altp2m operations are used exclusively by an in-guest
  *   agent to protect itself from the guest kernel and in-guest
  *   attackers.
- * 
+ *
  * - coordinated: An in-guest agent handles #VE and VMFUNCs locally,
  *   but makes requests of an agent running outside the domain for
  *   bigger changes (such as modifying altp2m entires).
@@ -4491,7 +4491,7 @@ static int hvmop_get_param(
  * to properly enable the 'internal' use case, as well as to avoid
  * fragmentation, all altp2m subops should come under this single
  * HVMOP.
- * 
+ *
  * Note that 'internal' mode (HVM_PARAM_ALTP2M == XEN_ALTP2M_mixed)
  * has not been evaluated for safety from a security perspective.
  * Before using this mode in a security-critical environment, each

xen/include/public/hvm/params.h

@@ -243,7 +243,7 @@
  * Note that 'mixed' mode has not been evaluated for safety from a
  * security perspective.  Before using this mode in a
  * security-critical environment, each subop should be evaluated for
- * safety, with unsafe subops blacklisted in xsm_hvm_altp2mhvm_op().
+ * safety, with unsafe subops blacklisted in XSM.
  */
 #define HVM_PARAM_ALTP2M       35
 #define XEN_ALTP2M_disabled      0