igb: fix link state on resume

On resume igb_vm_state_change() always calls igb_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 igb,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 igb_vm_state_change()
into igb_core_post_load() as e1000 does.

Buglink: https://issues.redhat.com/browse/RHEL-21867
Fixes: 3a977de ("Intrdocue igb device emulation")
Cc: akihiko.odaki@daynix.com
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/igb_core.c

@@ -160,14 +160,6 @@ igb_intmgr_timer_resume(IGBIntrDelayTimer *timer)
     }
 }
 
-static void
-igb_intmgr_timer_pause(IGBIntrDelayTimer *timer)
-{
-    if (timer->running) {
-        timer_del(timer->timer);
-    }
-}
-
 static void
 igb_intrmgr_on_msix_throttling_timer(void *opaque)
 {
@@ -212,16 +204,6 @@ igb_intrmgr_resume(IGBCore *core)
     }
 }
 
-static void
-igb_intrmgr_pause(IGBCore *core)
-{
-    int i;
-
-    for (i = 0; i < IGB_INTR_NUM; i++) {
-        igb_intmgr_timer_pause(&core->eitr[i]);
-    }
-}
-
 static void
 igb_intrmgr_reset(IGBCore *core)
 {
@@ -4290,12 +4272,6 @@ igb_core_read(IGBCore *core, hwaddr addr, unsigned size)
     return 0;
 }
 
-static inline void
-igb_autoneg_pause(IGBCore *core)
-{
-    timer_del(core->autoneg_timer);
-}
-
 static void
 igb_autoneg_resume(IGBCore *core)
 {
@@ -4307,22 +4283,6 @@ igb_autoneg_resume(IGBCore *core)
     }
 }
 
-static void
-igb_vm_state_change(void *opaque, bool running, RunState state)
-{
-    IGBCore *core = opaque;
-
-    if (running) {
-        trace_e1000e_vm_state_running();
-        igb_intrmgr_resume(core);
-        igb_autoneg_resume(core);
-    } else {
-        trace_e1000e_vm_state_stopped();
-        igb_autoneg_pause(core);
-        igb_intrmgr_pause(core);
-    }
-}
-
 void
 igb_core_pci_realize(IGBCore        *core,
                      const uint16_t *eeprom_templ,
@@ -4335,8 +4295,6 @@ igb_core_pci_realize(IGBCore        *core,
                                        igb_autoneg_timer, core);
     igb_intrmgr_pci_realize(core);
 
-    core->vmstate = qemu_add_vm_change_state_handler(igb_vm_state_change, core);
-
     for (i = 0; i < IGB_NUM_QUEUES; i++) {
         net_tx_pkt_init(&core->tx[i].tx_pkt, E1000E_MAX_TX_FRAGS);
     }
@@ -4360,8 +4318,6 @@ igb_core_pci_uninit(IGBCore *core)
 
     igb_intrmgr_pci_unint(core);
 
-    qemu_del_vm_change_state_handler(core->vmstate);
-
     for (i = 0; i < IGB_NUM_QUEUES; i++) {
         net_tx_pkt_uninit(core->tx[i].tx_pkt);
     }
@@ -4586,5 +4542,12 @@ igb_core_post_load(IGBCore *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
+     */
+    igb_intrmgr_resume(core);
+    igb_autoneg_resume(core);
+
     return 0;
 }

hw/net/igb_core.h

@@ -90,8 +90,6 @@ struct IGBCore {
 
     IGBIntrDelayTimer eitr[IGB_INTR_NUM];
 
-    VMChangeStateEntry *vmstate;
-
     uint32_t eitr_guest_value[IGB_INTR_NUM];
 
     uint8_t permanent_mac[ETH_ALEN];