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 is caused because spapr_core_unplug() assumes cpu_dt_id == core_id. Even if it happens to be the case when the host and guest have the same number of threads per core, it is conceptually wrong and we may pass a bogus id to spapr_dr_connector_by_id() and spapr_core_release() crashes. Let's use cc->core_id, which is the id that was used to create th DR connector. Signed-off-by: Greg Kurz <[email protected]> --- hw/ppc/spapr_cpu_core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c index 70b6b0b5ee17..106eaf45b399 100644 --- a/hw/ppc/spapr_cpu_core.c +++ b/hw/ppc/spapr_cpu_core.c @@ -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;
