spapr: ensure device trees are always associated with DRC

There are possible racing situations involving hotplug events and
guest migration. For cases where a hotplug event is migrated, or
the guest is in the process of fetching device tree at the time of
migration, we need to ensure the device tree is created and
associated with the corresponding DRC for devices that were
hotplugged on the source, but 'coldplugged' on the target.

Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

2 files changed, 11 insertions, 17 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 3b0845f158..44e401ae99 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2136,15 +2136,6 @@ static void spapr_add_lmbs(DeviceState *dev, uint64_t addr, uint64_t size,
     int i, fdt_offset, fdt_size;
     void *fdt;
 
-    /*
-     * Check for DRC connectors and send hotplug notification to the
-     * guest only in case of hotplugged memory. This allows cold plugged
-     * memory to be specified at boot time.
-     */
-    if (!dev->hotplugged) {
-        return;
-    }
-
     for (i = 0; i < nr_lmbs; i++) {
         drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_LMB,
                 addr/SPAPR_MEMORY_BLOCK_SIZE);
@@ -2158,7 +2149,12 @@ static void spapr_add_lmbs(DeviceState *dev, uint64_t addr, uint64_t size,
         drck->attach(drc, dev, fdt, fdt_offset, !dev->hotplugged, errp);
         addr += SPAPR_MEMORY_BLOCK_SIZE;
     }
-    spapr_hotplug_req_add_by_count(SPAPR_DR_CONNECTOR_TYPE_LMB, nr_lmbs);
+    /* send hotplug notification to the
+     * guest only in case of hotplugged memory
+     */
+    if (dev->hotplugged) {
+       spapr_hotplug_req_add_by_count(SPAPR_DR_CONNECTOR_TYPE_LMB, nr_lmbs);
+    }
 }
 
 static void spapr_memory_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index e55b505c96..91a356f851 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -1093,13 +1093,11 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
         spapr_tce_set_need_vfio(tcet, true);
     }
 
-    if (dev->hotplugged) {
-        fdt = create_device_tree(&fdt_size);
-        fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0);
-        if (!fdt_start_offset) {
-            error_setg(errp, "Failed to create pci child device tree node");
-            goto out;
-        }
+    fdt = create_device_tree(&fdt_size);
+    fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0);
+    if (!fdt_start_offset) {
+        error_setg(errp, "Failed to create pci child device tree node");
+        goto out;
     }
 
     drck->attach(drc, DEVICE(pdev),