numa: API to lookup NUMA node by address

Introduce an API numa_get_node(ram_addr_t addr, Error **errp) that
returns the NUMA node to which the given address belongs to. This
API works uniformly for both boot time as well as hotplugged memory.

This API is needed by sPAPR PowerPC to support
ibm,dynamic-reconfiguration-memory device tree node which is needed for
memory hotplug.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

diff --git a/include/sysemu/numa.h b/include/sysemu/numa.h
index 717636406295ccebb0dde43273c9bf7dab935e0d..a6392bc50f9a59a570813cc8d94868b812cf2ed6 100644 (file)
--- a/include/sysemu/numa.h
+++ b/include/sysemu/numa.h
@@ -31,5 +31,6 @@ void query_numa_node_mem(uint64_t node_mem[]);
 extern QemuOptsList qemu_numa_opts;
 void numa_set_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node);
 void numa_unset_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node);
+uint32_t numa_get_node(ram_addr_t addr, Error **errp);
 
 #endif

diff --git a/numa.c b/numa.c
index a73f6483ea27b0cc1818ca2a0d17eee0c0e9595c..3c8005913f2aa678bf2e05a2554e350afa4390c2 100644 (file)
--- a/numa.c
+++ b/numa.c
@@ -97,6 +97,47 @@ static void numa_set_mem_ranges(void)
     }
 }
 
+/*
+ * Check if @addr falls under NUMA @node.
+ */
+static bool numa_addr_belongs_to_node(ram_addr_t addr, uint32_t node)
+{
+    struct numa_addr_range *range;
+
+    QLIST_FOREACH(range, &numa_info[node].addr, entry) {
+        if (addr >= range->mem_start && addr <= range->mem_end) {
+            return true;
+        }
+    }
+    return false;
+}
+
+/*
+ * Given an address, return the index of the NUMA node to which the
+ * address belongs to.
+ */
+uint32_t numa_get_node(ram_addr_t addr, Error **errp)
+{
+    uint32_t i;
+
+    /* For non NUMA configurations, check if the addr falls under node 0 */
+    if (!nb_numa_nodes) {
+        if (numa_addr_belongs_to_node(addr, 0)) {
+            return 0;
+        }
+    }
+
+    for (i = 0; i < nb_numa_nodes; i++) {
+        if (numa_addr_belongs_to_node(addr, i)) {
+            return i;
+        }
+    }
+
+    error_setg(errp, "Address 0x" RAM_ADDR_FMT " doesn't belong to any "
+                "NUMA node", addr);
+    return -1;
+}
+
 static void numa_node_parse(NumaNodeOptions *node, QemuOpts *opts, Error **errp)
 {
     uint16_t nodenr;