[qemu-s390x] [PATCH v3 07/19] spapr_pci: add PHB unrealize

[Greg Kurz]

To support PHB hotplug we need to clean up lingering references,
memory, child properties, etc. prior to the PHB object being
finalized. Generally this will be called as a result of calling
object_unparent() on the PHB object, which in turn would normally
be called as the result of an unplug() operation.

When the PHB is finalized, child objects will be unparented in
turn, and finalized if the PHB was the only reference holder. so
we don't bother to explicitly unparent child objects of the PHB
(spapr_iommu, spapr_drc, etc).

The formula that gives the number of DMA windows is moved to an
inline function in the hw/pci-host/spapr.h header because it
will have other users.

The unrealize function is able to cope with partially realized PHBs.
It is hence used to implement proper rollback on the realize error
path. Note that older machines that used the legacy irq allocation
cannot support PHB hotplug, so we don't care to free their LSIs in
the unrealize function.

Signed-off-by: Michael Roth <address@hidden>
Signed-off-by: Greg Kurz <address@hidden>
---
v3: - don't free LSIs at unrealize
v2: - implement rollback with unrealize function
---
 hw/ppc/spapr_pci.c          |   63 ++++++++++++++++++++++++++++++++++++++++---
 include/hw/pci-host/spapr.h |    5 +++
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index f5f13a4d4816..0f6a173d5323 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -1559,6 +1559,56 @@ static void spapr_pci_unplug_request(HotplugHandler 
*plug_handler,
     }
 }
 
+static void spapr_phb_finalizefn(Object *obj)
+{
+    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(obj);
+
+    g_free(sphb->dtbusname);
+    sphb->dtbusname = NULL;
+}
+
+static void spapr_phb_unrealize(DeviceState *dev, Error **errp)
+{
+    SysBusDevice *s = SYS_BUS_DEVICE(dev);
+    PCIHostState *phb = PCI_HOST_BRIDGE(s);
+    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(phb);
+    sPAPRTCETable *tcet;
+    int i;
+    const unsigned windows_supported = spapr_phb_windows_supported(sphb);
+
+    if (sphb->msi) {
+        g_hash_table_unref(sphb->msi);
+        sphb->msi = NULL;
+    }
+
+    /*
+     * Remove IO/MMIO subregions and aliases, rest should get cleaned
+     * via PHB's unrealize->object_finalize
+     */
+    for (i = windows_supported - 1; i >= 0; i--) {
+        tcet = spapr_tce_find_by_liobn(sphb->dma_liobn[i]);
+        if (tcet) {
+            memory_region_del_subregion(&sphb->iommu_root,
+                                        spapr_tce_get_iommu(tcet));
+        }
+    }
+
+    QLIST_REMOVE(sphb, list);
+
+    memory_region_del_subregion(&sphb->iommu_root, &sphb->msiwindow);
+
+    address_space_destroy(&sphb->iommu_as);
+
+    qbus_set_hotplug_handler(BUS(phb->bus), NULL, &error_abort);
+    pci_unregister_root_bus(phb->bus);
+
+    memory_region_del_subregion(get_system_memory(), &sphb->iowindow);
+    if (sphb->mem64_win_pciaddr != (hwaddr)-1) {
+        memory_region_del_subregion(get_system_memory(), &sphb->mem64window);
+    }
+    memory_region_del_subregion(get_system_memory(), &sphb->mem32window);
+}
+
 static uint32_t spapr_phb_index_to_lsi(int phb_index, int irq_index)
 {
     return SPAPR_IRQ_PCI_LSI + phb_index * PCI_NUM_PINS + irq_index;
@@ -1592,8 +1642,7 @@ static void spapr_phb_realize(DeviceState *dev, Error 
**errp)
     PCIBus *bus;
     uint64_t msi_window_size = 4096;
     sPAPRTCETable *tcet;
-    const unsigned windows_supported =
-        sphb->ddw_enabled ? SPAPR_PCI_DMA_MAX_WINDOWS : 1;
+    const unsigned windows_supported = spapr_phb_windows_supported(sphb);
 
     if (!spapr) {
         error_setg(errp, TYPE_SPAPR_PCI_HOST_BRIDGE " needs a pseries 
machine");
@@ -1750,7 +1799,7 @@ static void spapr_phb_realize(DeviceState *dev, Error 
**errp)
             if (local_err) {
                 error_propagate_prepend(errp, local_err,
                                         "can't allocate LSIs: ");
-                return;
+                goto unrealize;
             }
             spapr_irq_set_type(spapr, irq, true);
         }
@@ -1778,13 +1827,17 @@ static void spapr_phb_realize(DeviceState *dev, Error 
**errp)
         if (!tcet) {
             error_setg(errp, "Creating window#%d failed for %s",
                        i, sphb->dtbusname);
-            return;
+            goto unrealize;
         }
         memory_region_add_subregion(&sphb->iommu_root, 0,
                                     spapr_tce_get_iommu(tcet));
     }
 
     sphb->msi = g_hash_table_new_full(g_int_hash, g_int_equal, g_free, g_free);
+    return;
+
+unrealize:
+    spapr_phb_unrealize(dev, NULL);
 }
 
 static int spapr_phb_children_reset(Object *child, void *opaque)
@@ -1983,6 +2036,7 @@ static void spapr_phb_class_init(ObjectClass *klass, void 
*data)
 
     hc->root_bus_path = spapr_phb_root_bus_path;
     dc->realize = spapr_phb_realize;
+    dc->unrealize = spapr_phb_unrealize;
     dc->props = spapr_phb_properties;
     dc->reset = spapr_phb_reset;
     dc->vmsd = &vmstate_spapr_pci;
@@ -1998,6 +2052,7 @@ static const TypeInfo spapr_phb_info = {
     .name          = TYPE_SPAPR_PCI_HOST_BRIDGE,
     .parent        = TYPE_PCI_HOST_BRIDGE,
     .instance_size = sizeof(sPAPRPHBState),
+    .instance_finalize = spapr_phb_finalizefn,
     .class_init    = spapr_phb_class_init,
     .interfaces    = (InterfaceInfo[]) {
         { TYPE_HOTPLUG_HANDLER },
diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index bb0ae7fdd41d..2ab75e28dbb5 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -166,4 +166,9 @@ void spapr_phb_dma_reset(sPAPRPHBState *sphb);
 
 void spapr_phb_set_lsis(int index, sPAPRMachineState *spapr);
 
+static inline unsigned spapr_phb_windows_supported(sPAPRPHBState *sphb)
+{
+    return sphb->ddw_enabled ? SPAPR_PCI_DMA_MAX_WINDOWS : 1;
+}
+
 #endif /* PCI_HOST_SPAPR_H */