If CPU core addition or removal is allowed in random order leading to
holes in the core id range (and hence in the cpu_index range), migration
can fail as migration with holes in cpu_index range isn't yet handled
correctly.
Prevent this situation by enforcing the addition in contiguous order
and removal in LIFO order so that we never end up with holes in
cpu_index range.
Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
---
While there is work in progress to support migration when there are holes
in cpu_index range resulting from out-of-order plug or unplug, this patch
is intended as a last resort if no easy, risk-free and elegant solution
emerges before 2.7 dev cycle ends.
hw/ppc/spapr_cpu_core.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index bc52b3c..4bfc96b 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -126,12 +126,23 @@ static void spapr_core_release(DeviceState *dev, void
*opaque)
void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
Error **errp)
{
+ sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
CPUCore *cc = CPU_CORE(dev);
sPAPRDRConnector *drc =
spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id);
sPAPRDRConnectorClass *drck;
Error *local_err = NULL;
+ int smt = kvmppc_smt_threads();
+ int index = cc->core_id / smt;
+ int spapr_max_cores = max_cpus / smp_threads;
+ int i;
+ for (i = spapr_max_cores - 1; i > index; i--) {
+ if (spapr->cores[i]) {
+ error_setg(errp, "core-id %d should be removed first", i * smt);
+ return;
+ }
+ }
g_assert(drc);
drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
@@ -214,7 +225,7 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev,
DeviceState *dev,
sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(OBJECT(hotplug_dev));
sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
int spapr_max_cores = max_cpus / smp_threads;
- int index;
+ int index, i;
int smt = kvmppc_smt_threads();
Error *local_err = NULL;
CPUCore *cc = CPU_CORE(dev);
@@ -252,6 +263,14 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev,
DeviceState *dev,
goto out;
}
+ for (i = 0; i < index; i++) {
+ if (!spapr->cores[i]) {
+ error_setg(&local_err, "core-id %d should be added first",
+ i * smt);
+ goto out;
+ }
+ }
+
out:
g_free(base_core_type);
error_propagate(errp, local_err);
--
2.7.4
