xen/domctl: Merge set_max_evtchn into createdomain

set_max_evtchn is somewhat weird.  It was introduced with the event_fifo work,
but has never been used.  Still, it is a bounding on resources consumed by the
event channel infrastructure, and should be part of createdomain, rather than
editable after the fact.

Drop XEN_DOMCTL_set_max_evtchn completely (including XSM hooks and libxc
wrappers), and retain the functionality in XEN_DOMCTL_createdomain.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Christian Lindig <christian.lindig@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

tools/flask/policy/modules/dom0.te

@@ -38,7 +38,7 @@ allow dom0_t dom0_t:domain {
 	getpodtarget setpodtarget set_misc_info set_virq_handler
 };
 allow dom0_t dom0_t:domain2 {
-	set_cpuid gettsc settsc setscheduler set_max_evtchn set_vnumainfo
+	set_cpuid gettsc settsc setscheduler set_vnumainfo
 	get_vnumainfo psr_cmt_op psr_alloc set_gnttab_limits
 };
 allow dom0_t dom0_t:resource { add remove };

tools/flask/policy/modules/xen.if

@@ -51,7 +51,7 @@ define(`create_domain_common', `
 			getvcpuinfo getaddrsize getaffinity setaffinity
 			settime setdomainhandle getvcpucontext set_misc_info };
 	allow $1 $2:domain2 { set_cpuid settsc setscheduler setclaim
-			set_max_evtchn set_vnumainfo get_vnumainfo cacheflush
+			set_vnumainfo get_vnumainfo cacheflush
 			psr_cmt_op psr_alloc soft_reset set_gnttab_limits
 			resource_map };
 	allow $1 $2:security check_context;