xsm, argo: XSM control for any access to argo by a domain

Will inhibit initialization of the domain's argo data structure to
prevent receiving any messages or notifications and access to any of
the argo hypercall operations.

Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Tested-by: Chris Patterson <pattersonc@ainfosec.com>
Release-acked-by: Juergen Gross <jgross@suse.com>

tools/flask/policy/modules/guest_features.te

@@ -5,11 +5,11 @@ allow domain_type xen_t:xen tmem_op;
 # pmu_ctrl is for)
 allow domain_type xen_t:xen2 pmu_use;
 
-# Allow all domains:
+# Allow all domains to enable the Argo interdomain communication hypercall;
 # to register single-sender (unicast) rings to partner with any domain;
 # to register any-sender (wildcard) rings that can be sent to by any domain;
 # and send messages to rings.
-allow domain_type xen_t:argo { register_any_source };
+allow domain_type xen_t:argo { enable register_any_source };
 allow domain_type domain_type:argo { send register_single_source };
 
 # Allow guest console output to the serial console.  This is used by PV Linux