[Qemu-devel] [RFC v8.1 08/13] pci: add bus reset_notifiers callbacks for host bus reset

[Chen Fan <chen.fan.fnst@cn.fujitsu.com>]

Particularly, For vfio devices, Once need to recovery devices
by bus reset such as AER, we always need to reset the host bus
to recovery the devices under the bus, so we need to add pci bus
callbacks to specify to do host bus reset.

Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
---
 hw/pci/pci.c             | 16 ++++++++++++++++
 hw/pci/pci_bridge.c      |  5 +++++
 include/hw/pci/pci.h     |  4 ++++
 include/hw/pci/pci_bus.h |  2 ++
 4 files changed, 27 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 48f19a3..0878834 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -74,11 +74,27 @@ static const VMStateDescription vmstate_pcibus = {
     }
 };
 
+void pci_bus_add_reset_notifier(PCIBus *bus, Notifier *notify)
+{
+    notifier_list_add(&bus->reset_notifiers, notify);
+}
+
+void pci_bus_remove_reset_notifier(Notifier *notify)
+{
+    notifier_remove(notify);
+}
+
+void pci_bus_run_reset_notifier(PCIBus *bus, void *opaque)
+{
+    notifier_list_notify(&bus->reset_notifiers, opaque);
+}
+
 static void pci_bus_realize(BusState *qbus, Error **errp)
 {
     PCIBus *bus = PCI_BUS(qbus);
 
     vmstate_register(NULL, -1, &vmstate_pcibus, bus);
+    notifier_list_init(&bus->reset_notifiers);
 }
 
 static void pci_bus_unrealize(BusState *qbus, Error **errp)
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index 40c97b1..75d2b4b 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -267,6 +267,11 @@ void pci_bridge_write_config(PCIDevice *d,
 
     newctl = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
     if (~oldctl & newctl & PCI_BRIDGE_CTL_BUS_RESET) {
+        /*
+         * Notify all vfio-pci devices under the bus
+         * to do physical bus reset.
+         */
+        pci_for_each_bus(&s->sec_bus, pci_bus_run_reset_notifier, NULL);
         /* Trigger hot reset on 0->1 transition. */
         qbus_reset_all(&s->sec_bus.qbus);
     }
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 5d050c8..5a9357c 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -7,6 +7,7 @@
 #include "exec/memory.h"
 #include "sysemu/dma.h"
 #include "qapi/error.h"
+#include "qemu/notify.h"
 
 /* PCI includes legacy ISA access.  */
 #include "hw/isa/isa.h"
@@ -371,6 +372,9 @@ 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_add_reset_notifier(PCIBus *bus, Notifier *notify);
+void pci_bus_remove_reset_notifier(Notifier *notify);
+void pci_bus_run_reset_notifier(PCIBus *bus, void *opaque);
 
 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 fabaeee..3b551d7 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -29,6 +29,8 @@ struct PCIBus {
        Keep a count of the number of devices with raised IRQs.  */
     int nirq;
     int *irq_count;
+
+    NotifierList reset_notifiers;
 };
 
 typedef struct PCIBridgeWindows PCIBridgeWindows;
-- 
1.9.3