[Qemu-devel] [PATCH for 2.13 v3 2/2] Revert "spapr: Don't allow memory hotplug to memory less nodes"

[Serhii Popovych]

This reverts commit b556854bd8524c26b8be98ab1bfdf0826831e793.

Leave change @node type from uint32_t to to int from reverted commit
because node < 0 is always false.

Note that implementing capability or some trick to detect if guest
kernel does not support hot-add to memory: this returns previous
behavour where memory added to first non-empty node.

Signed-off-by: Serhii Popovych <address@hidden>
---
 hw/ppc/spapr.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index c05bbad..1e7983c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3488,28 +3488,6 @@ static void spapr_machine_device_plug(HotplugHandler 
*hotplug_dev,
             return;
         }
 
-        /*
-         * Currently PowerPC kernel doesn't allow hot-adding memory to
-         * memory-less node, but instead will silently add the memory
-         * to the first node that has some memory. This causes two
-         * unexpected behaviours for the user.
-         *
-         * - Memory gets hotplugged to a different node than what the user
-         *   specified.
-         * - Since pc-dimm subsystem in QEMU still thinks that memory belongs
-         *   to memory-less node, a reboot will set things accordingly
-         *   and the previously hotplugged memory now ends in the right node.
-         *   This appears as if some memory moved from one node to another.
-         *
-         * So until kernel starts supporting memory hotplug to memory-less
-         * nodes, just prevent such attempts upfront in QEMU.
-         */
-        if (nb_numa_nodes && !numa_info[node].node_mem) {
-            error_setg(errp, "Can't hotplug memory to memory-less node %d",
-                       node);
-            return;
-        }
-
         spapr_memory_plug(hotplug_dev, dev, node, errp);
     } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
         spapr_core_plug(hotplug_dev, dev, errp);
-- 
1.8.3.1