u8 partid;              /* partition ID from SAL */
        u8 version;
        u8 pad[6];              /* pad to u64 align */
-       u64 vars_pa;
+       volatile u64 vars_pa;
        u64 part_nasids[XP_NASID_MASK_WORDS] ____cacheline_aligned;
        u64 mach_nasids[XP_NASID_MASK_WORDS] ____cacheline_aligned;
 };
  * occupies half a cacheline.
  */
 struct xpc_vars_part {
-       u64 magic;
+       volatile u64 magic;
 
        u64 openclose_args_pa;  /* physical address of open and close args */
        u64 GPs_pa;             /* physical address of Get/Put values */
  * Define a Get/Put value pair (pointers) used with a message queue.
  */
 struct xpc_gp {
-       s64 get;        /* Get value */
-       s64 put;        /* Put value */
+       volatile s64 get;       /* Get value */
+       volatile s64 put;       /* Put value */
 };
 
 #define XPC_GP_SIZE \
  */
 struct xpc_notify {
        struct semaphore sema;          /* notify semaphore */
-       u8 type;                        /* type of notification */
+       volatile u8 type;                       /* type of notification */
 
        /* the following two fields are only used if type == XPC_N_CALL */
        xpc_notify_func func;           /* user's notify function */
 
        /* XPC infrastructure referencing and teardown control */
 
-       u8 setup_state;                 /* infrastructure setup state */
+       volatile u8 setup_state;                        /* infrastructure setup state */
        wait_queue_head_t teardown_wq;  /* kthread waiting to teardown infra */
        atomic_t references;            /* #of references to infrastructure */
 
 
         * With the setting of the partition setup_state to XPC_P_SETUP, we're
         * declaring that this partition is ready to go.
         */
-       (volatile u8) part->setup_state = XPC_P_SETUP;
+       part->setup_state = XPC_P_SETUP;
 
 
        /*
        xpc_vars_part[partid].IPI_phys_cpuid =
                                        cpu_physical_id(smp_processor_id());
        xpc_vars_part[partid].nchannels = part->nchannels;
-       (volatile u64) xpc_vars_part[partid].magic = XPC_VP_MAGIC1;
+       xpc_vars_part[partid].magic = XPC_VP_MAGIC1;
 
        return xpcSuccess;
 }
 
                /* let the other side know that we've pulled their variables */
 
-               (volatile u64) xpc_vars_part[partid].magic = XPC_VP_MAGIC2;
+               xpc_vars_part[partid].magic = XPC_VP_MAGIC2;
        }
 
        if (pulled_entry->magic == XPC_VP_MAGIC1) {
                 */
                xpc_clear_local_msgqueue_flags(ch);
 
-               (volatile s64) ch->w_remote_GP.get = ch->remote_GP.get;
+               ch->w_remote_GP.get = ch->remote_GP.get;
 
                dev_dbg(xpc_chan, "w_remote_GP.get changed to %ld, partid=%d, "
                        "channel=%d\n", ch->w_remote_GP.get, ch->partid,
                 */
                xpc_clear_remote_msgqueue_flags(ch);
 
-               (volatile s64) ch->w_remote_GP.put = ch->remote_GP.put;
+               ch->w_remote_GP.put = ch->remote_GP.put;
 
                dev_dbg(xpc_chan, "w_remote_GP.put changed to %ld, partid=%d, "
                        "channel=%d\n", ch->w_remote_GP.put, ch->partid,
                notify = &ch->notify_queue[msg_number % ch->local_nentries];
                notify->func = func;
                notify->key = key;
-               (volatile u8) notify->type = notify_type;
+               notify->type = notify_type;
 
                // >>> is a mb() needed here?