[Qemu-devel] [PATCH 1/8] spapr-iommu: add a bus for spapr-iommu devices

[Alexey Kardashevskiy <aik@ozlabs.ru>]

At the moment sPAPR IOMMU table is a device which participates in
a migration stream. Normally QEMU uses a get_dev_path() hook from
the device's bus to compose the section name and @instance_id which are
used to match the section to the real device. This works till the user
changes the device order in the command line - if this happens,
devices get other instance_id's and migration fails.

This adds a TCE bridge bus device per sPAPR machine and places all sPAPR
IOMMU devices onto it.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 hw/ppc/spapr.c         |  3 +++
 hw/ppc/spapr_iommu.c   | 59 +++++++++++++++++++++++++++++++++++++++++++++++++-
 include/hw/ppc/spapr.h |  7 ++++++
 3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 5c9a154..12adc21 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1263,6 +1263,9 @@ static void ppc_spapr_init(QEMUMachineInitArgs *args)
     /* Set up EPOW events infrastructure */
     spapr_events_init(spapr);
 
+    /* Set up TCE IOMMUs bus */
+    spapr->tce_bus = spapr_tce_bus_init();
+
     /* Set up VIO bus */
     spapr->vio_bus = spapr_vio_bus_init();
 
diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index d9fe946..7db0acf 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -157,7 +157,7 @@ sPAPRTCETable *spapr_tce_new_table(DeviceState *owner, uint32_t liobn, size_t wi
         return NULL;
     }
 
-    tcet = SPAPR_TCE_TABLE(object_new(TYPE_SPAPR_TCE_TABLE));
+    tcet = SPAPR_TCE_TABLE(qdev_create(spapr->tce_bus, TYPE_SPAPR_TCE_TABLE));
     tcet->liobn = liobn;
     tcet->window_size = window_size;
 
@@ -342,9 +342,66 @@ static TypeInfo spapr_tce_table_info = {
     .instance_finalize = spapr_tce_table_finalize,
 };
 
+static char *spapr_tce_bus_get_dev_name(DeviceState *qdev)
+{
+    sPAPRTCETable *tcet = SPAPR_TCE_TABLE(qdev);
+    char *name;
+
+    name = g_strdup_printf("liobn@%x", tcet->liobn);
+    return name;
+}
+
+static void spapr_tce_bus_class_init(ObjectClass *klass, void *data)
+{
+    BusClass *k = BUS_CLASS(klass);
+
+    k->get_dev_path = spapr_tce_bus_get_dev_name;
+}
+
+static const TypeInfo spapr_tce_bus_info = {
+    .name = TYPE_SPAPR_TCE_BUS,
+    .parent = TYPE_BUS,
+    .class_init = spapr_tce_bus_class_init,
+    .instance_size = sizeof(BusState),
+};
+
+static int spapr_tce_bridge_init(SysBusDevice *dev)
+{
+    /* nothing */
+    return 0;
+}
+
+static void spapr_tce_bridge_class_init(ObjectClass *klass, void *data)
+{
+    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
+
+    k->init = spapr_tce_bridge_init;
+}
+
+static const TypeInfo spapr_tce_bridge_info = {
+    .name          = "spapr-tce-bridge",
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(SysBusDevice),
+    .class_init    = spapr_tce_bridge_class_init,
+};
+
 static void register_types(void)
 {
     type_register_static(&spapr_tce_table_info);
+    type_register_static(&spapr_tce_bridge_info);
+    type_register_static(&spapr_tce_bus_info);
+}
+
+BusState *spapr_tce_bus_init(void)
+{
+    DeviceState *dev;
+
+    /* Create bridge device */
+    dev = qdev_create(NULL, spapr_tce_bridge_info.name);
+    qdev_init_nofail(dev);
+
+    /* Create bus on bridge device */
+    return qbus_create(TYPE_SPAPR_TCE_BUS, dev, "spapr-tce");
 }
 
 type_init(register_types);
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 449fc7c..18332fd 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -12,6 +12,7 @@ struct sPAPRNVRAM;
 
 typedef struct sPAPREnvironment {
     struct VIOsPAPRBus *vio_bus;
+    BusState *tce_bus;
     QLIST_HEAD(, sPAPRPHBState) phbs;
     hwaddr msi_win_addr;
     MemoryRegion msiwindow;
@@ -405,4 +406,10 @@ int spapr_dma_dt(void *fdt, int node_off, const char *propname,
 int spapr_tcet_dma_dt(void *fdt, int node_off, const char *propname,
                       sPAPRTCETable *tcet);
 
+#define TYPE_SPAPR_TCE_BUS "spapr-tce-bus"
+#define SPAPR_TCE_BUS(obj) \
+    OBJECT_CHECK(BusState, (obj), TYPE_SPAPR_TCE_BUS)
+
+BusState *spapr_tce_bus_init(void);
+
 #endif /* !defined (__HW_SPAPR_H__) */
-- 
1.8.4.rc4