diff --git a/tools/libxc/xc_tmem.c b/tools/libxc/xc_tmem.c
index 74d2d85..cb0dfa1 100644
--- a/tools/libxc/xc_tmem.c
+++ b/tools/libxc/xc_tmem.c
@@ -87,7 +87,7 @@ int xc_tmem_control(xc_interface *xch,
         }
     }
 
-    set_xen_guest_handle(sysctl.u.tmem_op.buf, buf);
+    set_xen_guest_handle(sysctl.u.tmem_op.u.buf, buf);
 
     rc = do_sysctl(xch, &sysctl);
 
@@ -133,7 +133,7 @@ int xc_tmem_control_oid(xc_interface *xch,
         }
     }
 
-    set_xen_guest_handle(sysctl.u.tmem_op.buf, buf);
+    set_xen_guest_handle(sysctl.u.tmem_op.u.buf, buf);
 
     rc = do_sysctl(xch, &sysctl);
 
diff --git a/xen/common/tmem.c b/xen/common/tmem.c
index 27164ce..ab354b6 100644
--- a/xen/common/tmem.c
+++ b/xen/common/tmem.c
@@ -1843,19 +1843,19 @@ int do_tmem_control(struct xen_sysctl_tmem_op *op)
     case XEN_SYSCTL_TMEM_OP_RESTORE_BEGIN:
     case XEN_SYSCTL_TMEM_OP_SAVE_END:
         ret = tmemc_save_subop(op->cli_id, pool_id, cmd,
-                               guest_handle_cast(op->buf, char), op->arg1);
+                               guest_handle_cast(op->u.buf, char), op->arg1);
         break;
     case XEN_SYSCTL_TMEM_OP_SAVE_GET_NEXT_PAGE:
         ret = tmemc_save_get_next_page(op->cli_id, pool_id,
-                                       guest_handle_cast(op->buf, char), op->arg1);
+                                       guest_handle_cast(op->u.buf, char), op->arg1);
         break;
     case XEN_SYSCTL_TMEM_OP_SAVE_GET_NEXT_INV:
         ret = tmemc_save_get_next_inv(op->cli_id,
-                                      guest_handle_cast(op->buf, char), op->arg1);
+                                      guest_handle_cast(op->u.buf, char), op->arg1);
         break;
     case XEN_SYSCTL_TMEM_OP_RESTORE_PUT_PAGE:
         ret = tmemc_restore_put_page(op->cli_id, pool_id, oidp, op->arg2,
-                                     guest_handle_cast(op->buf, char), op->arg1);
+                                     guest_handle_cast(op->u.buf, char), op->arg1);
         break;
     case XEN_SYSCTL_TMEM_OP_RESTORE_FLUSH_PAGE:
         ret = tmemc_restore_flush_page(op->cli_id, pool_id, oidp, op->arg2);
diff --git a/xen/common/tmem_control.c b/xen/common/tmem_control.c
index 8bb9d48..942d4c9 100644
--- a/xen/common/tmem_control.c
+++ b/xen/common/tmem_control.c
@@ -258,7 +258,7 @@ static int tmemc_list(domid_t cli_id, tmem_cli_va_param_t buf, uint32_t len,
     return 0;
 }
 
-static int __tmemc_set_var(struct client *client, uint32_t subop,
+static int __tmemc_set_var(struct client *client,
                            XEN_GUEST_HANDLE_PARAM(xen_sysctl_tmem_client_t) buf)
 {
     domid_t cli_id = client->cli_id;
@@ -267,11 +267,6 @@ static int __tmemc_set_var(struct client *client, uint32_t subop,
 
     ASSERT(client);
 
-    if ( subop != XEN_SYSCTL_TMEM_OP_SET_CLIENT_INFO )
-    {
-        tmem_client_warn("tmem: unknown subop %d for tmemc_set_var\n", subop);
-        return -1;
-    }
     if ( copy_from_guest(&info, buf, 1) )
         return -EFAULT;
 
@@ -296,20 +291,17 @@ static int __tmemc_set_var(struct client *client, uint32_t subop,
     return 0;
 }
 
-static int tmemc_set_var(domid_t cli_id, uint32_t subop,
-                         XEN_GUEST_HANDLE_PARAM(void) buf)
+static int tmemc_set_client_info(domid_t cli_id,
+                                 XEN_GUEST_HANDLE_PARAM(xen_sysctl_tmem_client_t) info)
 {
     struct client *client;
     int ret = -ENOENT;
-    XEN_GUEST_HANDLE_PARAM(xen_sysctl_tmem_client_t) info;
-
-    info = guest_handle_cast(buf, xen_sysctl_tmem_client_t);
 
     if ( cli_id == TMEM_CLI_ID_NULL )
     {
         list_for_each_entry(client,&tmem_global.client_list,client_list)
         {
-            ret =  __tmemc_set_var(client, subop, info);
+            ret =  __tmemc_set_var(client, info);
             if (ret)
                 break;
         }
@@ -318,11 +310,32 @@ static int tmemc_set_var(domid_t cli_id, uint32_t subop,
     {
         client = tmem_client_from_cli_id(cli_id);
         if ( client )
-            ret = __tmemc_set_var(client, subop, info);
+            ret = __tmemc_set_var(client, info);
     }
     return ret;
 }
 
+static int tmemc_get_client_info(int cli_id,
+                                 XEN_GUEST_HANDLE_PARAM(xen_sysctl_tmem_client_t) info)
+{
+    struct client *client = tmem_client_from_cli_id(cli_id);
+
+    if ( client )
+    {
+        if ( copy_to_guest(info, &client->info, 1) )
+            return  -EFAULT;
+    }
+    else
+    {
+            xen_sysctl_tmem_client_t generic = { .version = TMEM_SPEC_VERSION,
+                                                 .maxpools = MAX_POOLS_PER_DOMAIN };
+        if ( copy_to_guest(info, &generic, 1) )
+            return -EFAULT;
+    }
+
+    return 0;
+}
+
 static int tmemc_save_subop(int cli_id, uint32_t pool_id, uint32_t subop,
                             XEN_GUEST_HANDLE_PARAM(void) buf, uint32_t arg1)
 {
@@ -330,27 +343,9 @@ static int tmemc_save_subop(int cli_id, uint32_t pool_id, uint32_t subop,
     struct tmem_pool *pool = (client == NULL || pool_id >= MAX_POOLS_PER_DOMAIN)
                    ? NULL : client->pools[pool_id];
     int rc = -1;
-    XEN_GUEST_HANDLE_PARAM(xen_sysctl_tmem_client_t) info;
 
     switch(subop)
     {
-    case XEN_SYSCTL_TMEM_OP_GET_CLIENT_INFO:
-        rc = 0;
-        info = guest_handle_cast(buf, xen_sysctl_tmem_client_t);
-        if ( client )
-        {
-            if ( copy_to_guest(info, &client->info, 1) )
-                rc = -EFAULT;
-        }
-        else
-        {
-            xen_sysctl_tmem_client_t generic = { .version = TMEM_SPEC_VERSION,
-                                                 .maxpools = MAX_POOLS_PER_DOMAIN };
-
-            if ( copy_to_guest(info, &generic, 1) )
-                rc = -EFAULT;
-        }
-        break;
     case XEN_SYSCTL_TMEM_OP_SAVE_GET_POOL_FLAGS:
          if ( pool == NULL )
              break;
@@ -400,21 +395,24 @@ int tmem_control(struct xen_sysctl_tmem_op *op)
         break;
     case XEN_SYSCTL_TMEM_OP_LIST:
         ret = tmemc_list(op->cli_id,
-                         guest_handle_cast(op->buf, char), op->arg1, op->arg2);
+                         guest_handle_cast(op->u.buf, char), op->arg1, op->arg2);
         break;
     case XEN_SYSCTL_TMEM_OP_SET_CLIENT_INFO:
-        ret = tmemc_set_var(op->cli_id, cmd,
-                            guest_handle_cast(op->buf, void));
+        ret = tmemc_set_client_info(op->cli_id,
+                                    guest_handle_cast(op->u.client, xen_sysctl_tmem_client_t));
         break;
     case XEN_SYSCTL_TMEM_OP_QUERY_FREEABLE_MB:
         ret = tmem_freeable_pages() >> (20 - PAGE_SHIFT);
         break;
     case XEN_SYSCTL_TMEM_OP_GET_CLIENT_INFO:
+        ret = tmemc_get_client_info(op->cli_id,
+                                    guest_handle_cast(op->u.client, xen_sysctl_tmem_client_t));
+        break;
     case XEN_SYSCTL_TMEM_OP_SAVE_GET_POOL_FLAGS:
     case XEN_SYSCTL_TMEM_OP_SAVE_GET_POOL_NPAGES:
     case XEN_SYSCTL_TMEM_OP_SAVE_GET_POOL_UUID:
         ret = tmemc_save_subop(op->cli_id, pool_id, cmd,
-                               guest_handle_cast(op->buf, void), op->arg1);
+                               guest_handle_cast(op->u.buf, void), op->arg1);
         break;
     default:
         ret = do_tmem_control(op);
diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 27e051b..52898a7 100644
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -782,8 +782,8 @@ struct tmem_handle {
 };
 
 /*
- * XEN_SYSCTL_TMEM_OP_[GET,SAVE]_CLIENT overrides the 'buf' in
- * xen_sysctl_tmem_op with this structure - and contain data used
+ * XEN_SYSCTL_TMEM_OP_[GET,SAVE]_CLIENT uses the 'client' in
+ * xen_sysctl_tmem_op with this structure - which is mostly used
  * during migration.
  */
 struct tmem_client {
@@ -812,8 +812,11 @@ struct xen_sysctl_tmem_op {
     uint32_t arg2;      /* IN: If not applicable to command use 0. */
     uint32_t pad;       /* Padding so structure is the same under 32 and 64. */
     xen_tmem_oid_t oid; /* IN: If not applicable to command use 0s. */
-    XEN_GUEST_HANDLE_64(char) buf; /* IN/OUT: Buffer to save/restore,
-                                      and set/get ops. */
+    union {
+        XEN_GUEST_HANDLE_64(char) buf; /* IN/OUT: Buffer to save/restore */
+        XEN_GUEST_HANDLE_64(xen_sysctl_tmem_client_t) client; /* IN/OUT for */
+                        /*  XEN_SYSCTL_TMEM_OP_[GET,SAVE]_CLIENT. */
+    } u;
 };
 typedef struct xen_sysctl_tmem_op xen_sysctl_tmem_op_t;
 DEFINE_XEN_GUEST_HANDLE(xen_sysctl_tmem_op_t);
