[Qemu-devel] [PATCH v16 10/14] pci: introduce pci bus pre reset

[Cao jin]

From: Chen Fan <address@hidden>

avoid repeat bus reset, here introduce a sequence ID for each time
bus hot reset, so each vfio device could know whether they've already
been reset for that sequence ID.

Signed-off-by: Chen Fan <address@hidden>
---
 hw/pci/pci.c             | 13 +++++++++++++
 hw/pci/pci_bridge.c      |  3 +++
 include/hw/pci/pci.h     |  1 +
 include/hw/pci/pci_bus.h |  3 +++
 4 files changed, 20 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index f6ca6ef..ceb72d5 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -91,6 +91,18 @@ static void pci_bus_unrealize(BusState *qbus, Error **errp)
     vmstate_unregister(NULL, &vmstate_pcibus, bus);
 }
 
+void pci_bus_pre_reset(PCIBus *bus, uint32_t seqid)
+{
+    PCIBus *sec;
+
+    bus->in_reset = true;
+    bus->reset_seqid = seqid;
+
+    QLIST_FOREACH(sec, &bus->child, sibling) {
+        pci_bus_pre_reset(sec, seqid);
+    }
+}
+
 static bool pcibus_is_root(PCIBus *bus)
 {
     return !bus->parent_dev;
@@ -276,6 +288,7 @@ static void pcibus_reset(BusState *qbus)
     for (i = 0; i < bus->nirq; i++) {
         assert(bus->irq_count[i] == 0);
     }
+    bus->in_reset = false;
 }
 
 static void pci_host_bus_register(PCIBus *bus, DeviceState *parent)
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index 40c97b1..c7f15a1 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -268,6 +268,9 @@ void pci_bridge_write_config(PCIDevice *d,
     newctl = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
     if (~oldctl & newctl & PCI_BRIDGE_CTL_BUS_RESET) {
         /* Trigger hot reset on 0->1 transition. */
+        uint32_t seqid = s->sec_bus.reset_seqid++;
+
+        pci_bus_pre_reset(&s->sec_bus, seqid ? seqid : 1);
         qbus_reset_all(&s->sec_bus.qbus);
     }
 }
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 379b6e1..b811279 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -381,6 +381,7 @@ void pci_bus_fire_intx_routing_notifier(PCIBus *bus);
 void pci_device_set_intx_routing_notifier(PCIDevice *dev,
                                           PCIINTxRoutingNotifier notifier);
 void pci_device_reset(PCIDevice *dev);
+void pci_bus_pre_reset(PCIBus *bus, uint32_t seqid);
 
 PCIDevice *pci_nic_init_nofail(NICInfo *nd, PCIBus *rootbus,
                                const char *default_model,
diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index 7812fa9..dd6aaf1 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -40,6 +40,9 @@ struct PCIBus {
     int nirq;
     int *irq_count;
 
+    bool in_reset;
+    uint32_t reset_seqid;
+
     NotifierWithReturnList hotplug_notifiers;
 };
 
-- 
1.9.3