- enable remembering of device memory ranges set by PCI and

told to kernel
  - makes VM ask the kernel if a certain process is allowed
    to map in a range of physical memory (VM rounds it to page
    boundaries afterwards - but it's impossible to map anything
    smaller otherwise so I assume this is safe, i.e. there won't
    be anything else in that page; certainly no regular memory)
  - VM permission check cleanup (no more hardcoded calls, less
    hardcoded logic, more readable main loop), a loose end left
    by GQ
  - remove do_copy warning, as the ipc server triggers this but
    it's no more harmful than the special cases already excluded
    explicitly (VFS, PM, etc).

lib/syslib/sys_privctl.c

@@ -10,3 +10,15 @@ int sys_privctl(endpoint_t proc_ep, int request, void *p)
 
   return _taskcall(SYSTASK, SYS_PRIVCTL, &m);
 }
+
+int sys_privquery_mem(endpoint_t proc_ep, phys_bytes start, phys_bytes len)
+{
+  message m;
+
+  m.CTL_ENDPT = proc_ep;
+  m.CTL_REQUEST = SYS_PRIV_QUERY_MEM;
+  m.CTL_PHYSSTART = start;
+  m.CTL_PHYSLEN = len;
+
+  return _taskcall(SYSTASK, SYS_PRIVCTL, &m);
+}