Commit 44d691f7 authored by Greg Kurz's avatar Greg Kurz Committed by David Gibson
Browse files

spapr: fix core unplug crash 



If the host has 8 threads/core and the guest is started with:

-smp cores=1,threads=4,maxcpus=12

It is possible to crash QEMU by doing:

(qemu) device_add host-spapr-cpu-core,core-id=16,id=foo
(qemu) device_del foo
Segmentation fault

This happens because spapr_core_unplug() assumes cpu_dt_id == core_id.
As long as cpu_dt_id is derived from the non-table cpu_index, this is
only true when you plug cores with contiguous ids.

It is safer to be consistent: the DR connector was created with an
index that is immediately written to cc->core_id, and spapr_core_plug()
also relies on cc->core_id.

Let's use it also in spapr_core_unplug().

Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Reviewed-by: default avatarBharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 6b92bbfe

hw/ppc/spapr_cpu_core.c

+2 −4
Original line number Diff line number Diff line
@@ -126,11 +126,9 @@ static void spapr_core_release(DeviceState *dev, void *opaque) 
void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,

                       Error **errp)

{

    sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev));

    PowerPCCPU *cpu = POWERPC_CPU(core->threads);

    int id = ppc_get_vcpu_dt_id(cpu);

    CPUCore *cc = CPU_CORE(dev);

    sPAPRDRConnector *drc =

        spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, id);

        spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id);

    sPAPRDRConnectorClass *drck;

    Error *local_err = NULL;