e1000e: fix link state on resume

On resume e1000e_vm_state_change() always calls e1000e_autoneg_resume()
that sets link_down to false, and thus activates the link even
if we have disabled it.

The problem can be reproduced starting qemu in paused state (-S) and
then set the link to down. When we resume the machine the link appears
to be up.

Reproducer:

   # qemu-system-x86_64 ... -device e1000e,netdev=netdev0,id=net0 -S

   {"execute": "qmp_capabilities" }
   {"execute": "set_link", "arguments": {"name": "net0", "up": false}}
   {"execute": "cont" }

To fix the problem, merge the content of e1000e_vm_state_change()
into e1000e_core_post_load() as e1000 does.

Buglink: https://issues.redhat.com/browse/RHEL-21867
Fixes: 6f3fbe4 ("net: Introduce e1000e device emulation")
Suggested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

hw/net/e1000e_core.c

@@ -123,14 +123,6 @@ e1000e_intmgr_timer_resume(E1000IntrDelayTimer *timer)
     }
 }
 
-static void
-e1000e_intmgr_timer_pause(E1000IntrDelayTimer *timer)
-{
-    if (timer->running) {
-        timer_del(timer->timer);
-    }
-}
-
 static inline void
 e1000e_intrmgr_stop_timer(E1000IntrDelayTimer *timer)
 {
@@ -398,24 +390,6 @@ e1000e_intrmgr_resume(E1000ECore *core)
     }
 }
 
-static void
-e1000e_intrmgr_pause(E1000ECore *core)
-{
-    int i;
-
-    e1000e_intmgr_timer_pause(&core->radv);
-    e1000e_intmgr_timer_pause(&core->rdtr);
-    e1000e_intmgr_timer_pause(&core->raid);
-    e1000e_intmgr_timer_pause(&core->tidv);
-    e1000e_intmgr_timer_pause(&core->tadv);
-
-    e1000e_intmgr_timer_pause(&core->itr);
-
-    for (i = 0; i < E1000E_MSIX_VEC_NUM; i++) {
-        e1000e_intmgr_timer_pause(&core->eitr[i]);
-    }
-}
-
 static void
 e1000e_intrmgr_reset(E1000ECore *core)
 {
@@ -3334,12 +3308,6 @@ e1000e_core_read(E1000ECore *core, hwaddr addr, unsigned size)
     return 0;
 }
 
-static inline void
-e1000e_autoneg_pause(E1000ECore *core)
-{
-    timer_del(core->autoneg_timer);
-}
-
 static void
 e1000e_autoneg_resume(E1000ECore *core)
 {
@@ -3351,22 +3319,6 @@ e1000e_autoneg_resume(E1000ECore *core)
     }
 }
 
-static void
-e1000e_vm_state_change(void *opaque, bool running, RunState state)
-{
-    E1000ECore *core = opaque;
-
-    if (running) {
-        trace_e1000e_vm_state_running();
-        e1000e_intrmgr_resume(core);
-        e1000e_autoneg_resume(core);
-    } else {
-        trace_e1000e_vm_state_stopped();
-        e1000e_autoneg_pause(core);
-        e1000e_intrmgr_pause(core);
-    }
-}
-
 void
 e1000e_core_pci_realize(E1000ECore     *core,
                         const uint16_t *eeprom_templ,
@@ -3379,9 +3331,6 @@ e1000e_core_pci_realize(E1000ECore     *core,
                                        e1000e_autoneg_timer, core);
     e1000e_intrmgr_pci_realize(core);
 
-    core->vmstate =
-        qemu_add_vm_change_state_handler(e1000e_vm_state_change, core);
-
     for (i = 0; i < E1000E_NUM_QUEUES; i++) {
         net_tx_pkt_init(&core->tx[i].tx_pkt, E1000E_MAX_TX_FRAGS);
     }
@@ -3405,8 +3354,6 @@ e1000e_core_pci_uninit(E1000ECore *core)
 
     e1000e_intrmgr_pci_unint(core);
 
-    qemu_del_vm_change_state_handler(core->vmstate);
-
     for (i = 0; i < E1000E_NUM_QUEUES; i++) {
         net_tx_pkt_uninit(core->tx[i].tx_pkt);
     }
@@ -3576,5 +3523,12 @@ e1000e_core_post_load(E1000ECore *core)
      */
     nc->link_down = (core->mac[STATUS] & E1000_STATUS_LU) == 0;
 
+    /*
+     * we need to restart intrmgr timers, as an older version of
+     * QEMU can have stopped them before migration
+     */
+    e1000e_intrmgr_resume(core);
+    e1000e_autoneg_resume(core);
+
     return 0;
 }

hw/net/e1000e_core.h

@@ -98,8 +98,6 @@ struct E1000Core {
 
     E1000IntrDelayTimer eitr[E1000E_MSIX_VEC_NUM];
 
-    VMChangeStateEntry *vmstate;
-
     uint32_t itr_guest_value;
     uint32_t eitr_guest_value[E1000E_MSIX_VEC_NUM];