hw/xen: use qemu_create_nic_bus_devices() to instantiate Xen NICs

When instantiating XenBus itself, for each NIC which is configured with
either the model unspecified, or set to to "xen" or "xen-net-device",
create a corresponding xen-net-device for it.

Now we can revert the previous more hackish version which relied on the
platform code explicitly registering the NICs on its own XenBus, having
returned the BusState* from xen_bus_init() itself.

This also fixes the setup for Xen PV guests, which was previously broken
in various ways and never actually managed to peer with the netdev.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

hw/i386/pc.c

@@ -1269,7 +1269,7 @@ void pc_basic_device_init(struct PCMachineState *pcms,
         if (pcms->bus) {
             pci_create_simple(pcms->bus, -1, "xen-platform");
         }
-        pcms->xenbus = xen_bus_init();
+        xen_bus_init();
         xen_be_init();
     }
 #endif
@@ -1297,8 +1297,7 @@ void pc_basic_device_init(struct PCMachineState *pcms,
                     pcms->vmport != ON_OFF_AUTO_ON);
 }
 
-void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus,
-                 BusState *xen_bus)
+void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus)
 {
     MachineClass *mc = MACHINE_CLASS(pcmc);
     bool default_is_ne2k = g_str_equal(mc->default_nic, TYPE_ISA_NE2000);
@@ -1306,14 +1305,6 @@ void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus,
 
     rom_set_order_override(FW_CFG_ORDER_OVERRIDE_NIC);
 
-    if (xen_bus) {
-        while ((nd = qemu_find_nic_info("xen-net-device", true, NULL))) {
-            DeviceState *dev = qdev_new("xen-net-device");
-            qdev_set_nic_properties(dev, nd);
-            qdev_realize_and_unref(dev, xen_bus, &error_fatal);
-        }
-    }
-
     while ((nd = qemu_find_nic_info(TYPE_ISA_NE2000, default_is_ne2k, NULL))) {
         pc_init_ne2k_isa(isa_bus, nd, &error_fatal);
     }

hw/i386/pc_piix.c

@@ -339,7 +339,7 @@ static void pc_init1(MachineState *machine,
     pc_basic_device_init(pcms, isa_bus, x86ms->gsi, rtc_state, true,
                          0x4);
 
-    pc_nic_init(pcmc, isa_bus, pci_bus, pcms->xenbus);
+    pc_nic_init(pcmc, isa_bus, pci_bus);
 
     if (pcmc->pci_enabled) {
         pc_cmos_init(pcms, idebus[0], idebus[1], rtc_state);

hw/i386/pc_q35.c

@@ -340,7 +340,7 @@ static void pc_q35_init(MachineState *machine)
 
     /* the rest devices to which pci devfn is automatically assigned */
     pc_vga_init(isa_bus, host_bus);
-    pc_nic_init(pcmc, isa_bus, host_bus, pcms->xenbus);
+    pc_nic_init(pcmc, isa_bus, host_bus);
 
     if (machine->nvdimms_state->is_enabled) {
         nvdimm_init_acpi_state(machine->nvdimms_state, system_io,

hw/xen/xen-bus.c

@@ -19,6 +19,7 @@
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "sysemu/sysemu.h"
+#include "net/net.h"
 #include "trace.h"
 
 static char *xen_device_get_backend_path(XenDevice *xendev)
@@ -1133,7 +1134,7 @@ static void xen_register_types(void)
 
 type_init(xen_register_types)
 
-BusState *xen_bus_init(void)
+void xen_bus_init(void)
 {
     DeviceState *dev = qdev_new(TYPE_XEN_BRIDGE);
     BusState *bus = qbus_new(TYPE_XEN_BUS, dev, NULL);
@@ -1141,5 +1142,6 @@ BusState *xen_bus_init(void)
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
     qbus_set_bus_hotplug_handler(bus);
 
-    return bus;
+    qemu_create_nic_bus_devices(bus, TYPE_XEN_DEVICE, "xen-net-device",
+                                "xen", "xen-net-device");
 }

hw/xen/xen_devconfig.c

@@ -46,31 +46,6 @@ static int xen_config_dev_all(char *fe, char *be)
 
 /* ------------------------------------------------------------- */
 
-int xen_config_dev_nic(NICInfo *nic)
-{
-    char fe[256], be[256];
-    char mac[20];
-    int vlan_id = -1;
-
-    net_hub_id_for_client(nic->netdev, &vlan_id);
-    snprintf(mac, sizeof(mac), "%02x:%02x:%02x:%02x:%02x:%02x",
-             nic->macaddr.a[0], nic->macaddr.a[1], nic->macaddr.a[2],
-             nic->macaddr.a[3], nic->macaddr.a[4], nic->macaddr.a[5]);
-    xen_pv_printf(NULL, 1, "config nic %d: mac=\"%s\"\n", vlan_id, mac);
-    xen_config_dev_dirs("vif", "qnic", vlan_id, fe, be, sizeof(fe));
-
-    /* frontend */
-    xenstore_write_int(fe, "handle",     vlan_id);
-    xenstore_write_str(fe, "mac",        mac);
-
-    /* backend */
-    xenstore_write_int(be, "handle",     vlan_id);
-    xenstore_write_str(be, "mac",        mac);
-
-    /* common stuff */
-    return xen_config_dev_all(fe, be);
-}
-
 int xen_config_dev_vfb(int vdev, const char *type)
 {
     char fe[256], be[256];

hw/xenpv/xen_machine_pv.c

@@ -32,8 +32,6 @@
 
 static void xen_init_pv(MachineState *machine)
 {
-    int i;
-
     setup_xen_backend_ops();
 
     /* Initialize backend core & drivers */
@@ -62,13 +60,6 @@ static void xen_init_pv(MachineState *machine)
         vga_interface_created = true;
     }
 
-    /* configure nics */
-    for (i = 0; i < nb_nics; i++) {
-        if (!nd_table[i].model || 0 != strcmp(nd_table[i].model, "xen"))
-            continue;
-        xen_config_dev_nic(nd_table + i);
-    }
-
     xen_bus_init();
 
     /* config cleanup hook */

include/hw/i386/pc.h

@@ -33,7 +33,6 @@ typedef struct PCMachineState {
 
     /* Pointers to devices and objects: */
     PCIBus *bus;
-    BusState *xenbus;
     I2CBus *smbus;
     PFlashCFI01 *flash[2];
     ISADevice *pcspk;
@@ -185,8 +184,7 @@ void pc_basic_device_init(struct PCMachineState *pcms,
 void pc_cmos_init(PCMachineState *pcms,
                   BusState *ide0, BusState *ide1,
                   ISADevice *s);
-void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus,
-                 BusState *xen_bus);
+void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus);
 
 void pc_i8259_create(ISABus *isa_bus, qemu_irq *i8259_irqs);
 

include/hw/xen/xen-bus.h

@@ -75,7 +75,7 @@ struct XenBusClass {
 OBJECT_DECLARE_TYPE(XenBus, XenBusClass,
                     XEN_BUS)
 
-BusState *xen_bus_init(void);
+void xen_bus_init(void);
 
 void xen_device_backend_set_state(XenDevice *xendev,
                                   enum xenbus_state state);

include/hw/xen/xen-legacy-backend.h

@@ -81,7 +81,6 @@ extern struct XenDevOps xen_usb_ops;          /* xen-usb.c         */
 
 /* configuration (aka xenbus setup) */
 void xen_config_cleanup(void);
-int xen_config_dev_nic(NICInfo *nic);
 int xen_config_dev_vfb(int vdev, const char *type);
 int xen_config_dev_vkbd(int vdev);
 int xen_config_dev_console(int vdev);