numa: cpu: calculate/set default node-ids after all -numa CLI options are parsed

Calculating default node-ids for CPUs in possible_cpu_arch_ids()
is rather fragile since defaults calculation uses nb_numa_nodes but
callback might be potentially called early before all -numa CLI
options are parsed, which would lead to cpus assigned only upto
nb_numa_nodes at the time possible_cpu_arch_ids() is called.

Issue was introduced by
(7c88e65 numa: mirror cpu to node mapping in MachineState::possible_cpus)
and for example CLI:
  -smp 4 -numa node,cpus=0 -numa node
would set props.node-id in possible_cpus array for every non
explicitly mapped CPU to the first node.

Issue is not visible to guest nor to mgmt interface due to
  1) implictly mapped cpus are forced to the first node in
     case of partial mapping
  2) in case of default mapping possible_cpu_arch_ids() is
     called after all -numa options are parsed (resulting
     in correct mapping).

However it's fragile to rely on late execution of
possible_cpu_arch_ids(), therefore add machine specific
callback that returns node-id for CPU and use it to calculate/
set defaults at machine_numa_finish_init() time when all -numa
options are parsed.

Reported-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1496314408-163972-1-git-send-email-imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 65d68bc50d517ff03da5e38d3eb371b483b0e9c9..9e18b410d7b85e9cfae6268a17f30480be6aa3ec 100644 (file)
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1554,6 +1554,11 @@ virt_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
     return possible_cpus->cpus[cpu_index].props;
 }
 
+static int64_t virt_get_default_cpu_node_id(const MachineState *ms, int idx)
+{
+    return idx % nb_numa_nodes;
+}
+
 static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
 {
     int n;
@@ -1572,14 +1577,6 @@ static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
             virt_cpu_mp_affinity(vms, n);
         ms->possible_cpus->cpus[n].props.has_thread_id = true;
         ms->possible_cpus->cpus[n].props.thread_id = n;
-
-        /* default distribution of CPUs over NUMA nodes */
-        if (nb_numa_nodes) {
-            /* preset values but do not enable them i.e. 'has_node_id = false',
-             * numa init code will enable them later if manual mapping wasn't
-             * present on CLI */
-            ms->possible_cpus->cpus[n].props.node_id = n % nb_numa_nodes;
-        }
     }
     return ms->possible_cpus;
 }
@@ -1603,6 +1600,7 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
     mc->possible_cpu_arch_ids = virt_possible_cpu_arch_ids;
     mc->cpu_index_to_instance_props = virt_cpu_index_to_props;
     mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a15");
+    mc->get_default_cpu_node_id = virt_get_default_cpu_node_id;
 }
 
 static const TypeInfo virt_machine_info = {

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 41b53a17ad3220d1b3b3b28a79f8fe673cc2193e..80647edc2a873da84d56775d0ffd48783a152224 100644 (file)
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -724,6 +724,7 @@ static void machine_numa_finish_init(MachineState *machine)
             /* fetch default mapping from board and enable it */
             CpuInstanceProperties props = cpu_slot->props;
 
+            props.node_id = mc->get_default_cpu_node_id(machine, i);
             if (!default_mapping) {
                 /* record slots with not set mapping,
                  * TODO: make it hard error in future */

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 2247ac0a01fc397d11fc549c36760b1b6a98bb46..610c65aeabb5574d640f80ecfe5d8534b6d9c007 100644 (file)
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2234,6 +2234,16 @@ pc_cpu_index_to_props(MachineState *ms, unsigned cpu_index)
     return possible_cpus->cpus[cpu_index].props;
 }
 
+static int64_t pc_get_default_cpu_node_id(const MachineState *ms, int idx)
+{
+   X86CPUTopoInfo topo;
+
+   assert(idx < ms->possible_cpus->len);
+   x86_topo_ids_from_apicid(ms->possible_cpus->cpus[idx].arch_id,
+                            smp_cores, smp_threads, &topo);
+   return topo.pkg_id % nb_numa_nodes;
+}
+
 static const CPUArchIdList *pc_possible_cpu_arch_ids(MachineState *ms)
 {
     int i;
@@ -2263,15 +2273,6 @@ static const CPUArchIdList *pc_possible_cpu_arch_ids(MachineState *ms)
         ms->possible_cpus->cpus[i].props.core_id = topo.core_id;
         ms->possible_cpus->cpus[i].props.has_thread_id = true;
         ms->possible_cpus->cpus[i].props.thread_id = topo.smt_id;
-
-        /* default distribution of CPUs over NUMA nodes */
-        if (nb_numa_nodes) {
-            /* preset values but do not enable them i.e. 'has_node_id = false',
-             * numa init code will enable them later if manual mapping wasn't
-             * present on CLI */
-            ms->possible_cpus->cpus[i].props.node_id =
-                topo.pkg_id % nb_numa_nodes;
-        }
     }
     return ms->possible_cpus;
 }
@@ -2316,6 +2317,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
     pcmc->linuxboot_dma_enabled = true;
     mc->get_hotplug_handler = pc_get_hotpug_handler;
     mc->cpu_index_to_instance_props = pc_cpu_index_to_props;
+    mc->get_default_cpu_node_id = pc_get_default_cpu_node_id;
     mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids;
     mc->has_hotpluggable_cpus = true;
     mc->default_boot_order = "cad";

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index f680f28a15eabc90f13a18e5e6a3ac27c213a355..17ea77618cb9c721cbc13f9bce2f0e411237b5c9 100644 (file)
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3404,6 +3404,11 @@ spapr_cpu_index_to_props(MachineState *machine, unsigned cpu_index)
     return core_slot->props;
 }
 
+static int64_t spapr_get_default_cpu_node_id(const MachineState *ms, int idx)
+{
+    return idx / smp_cores % nb_numa_nodes;
+}
+
 static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
 {
     int i;
@@ -3428,15 +3433,6 @@ static const CPUArchIdList *spapr_possible_cpu_arch_ids(MachineState *machine)
         machine->possible_cpus->cpus[i].arch_id = core_id;
         machine->possible_cpus->cpus[i].props.has_core_id = true;
         machine->possible_cpus->cpus[i].props.core_id = core_id;
-
-        /* default distribution of CPUs over NUMA nodes */
-        if (nb_numa_nodes) {
-            /* preset values but do not enable them i.e. 'has_node_id = false',
-             * numa init code will enable them later if manual mapping wasn't
-             * present on CLI */
-            machine->possible_cpus->cpus[i].props.node_id =
-                core_id / smp_threads / smp_cores % nb_numa_nodes;
-        }
     }
     return machine->possible_cpus;
 }
@@ -3587,6 +3583,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     hc->pre_plug = spapr_machine_device_pre_plug;
     hc->plug = spapr_machine_device_plug;
     mc->cpu_index_to_instance_props = spapr_cpu_index_to_props;
+    mc->get_default_cpu_node_id = spapr_get_default_cpu_node_id;
     mc->possible_cpu_arch_ids = spapr_possible_cpu_arch_ids;
     hc->unplug_request = spapr_machine_device_unplug_request;
 

diff --git a/include/hw/boards.h b/include/hw/boards.h
index 6b67adaef68b6d7a1cad2202189fbfc1fee85e16..156e0a57014f4944ea251aac8e1a83e8a58ba152 100644 (file)
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -123,6 +123,9 @@ typedef struct {
  *    Returns an array of @CPUArchId architecture-dependent CPU IDs
  *    which includes CPU IDs for present and possible to hotplug CPUs.
  *    Caller is responsible for freeing returned list.
+ * @get_default_cpu_node_id:
+ *    returns default board specific node_id value for CPU slot specified by
+ *    index @idx in @ms->possible_cpus[]
  * @has_hotpluggable_cpus:
  *    If true, board supports CPUs creation with -device/device_add.
  * @default_cpu_type:
@@ -196,6 +199,7 @@ struct MachineClass {
     CpuInstanceProperties (*cpu_index_to_instance_props)(MachineState *machine,
                                                          unsigned cpu_index);
     const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine);
+    int64_t (*get_default_cpu_node_id)(const MachineState *ms, int idx);
 };
 
 /**