From b65a2e8f5076b1bd0e11a18d13b1d6e0225e047f Mon Sep 17 00:00:00 2001
From: David Gibson <dgibson@redhat.com>
Date: Tue, 12 Jul 2016 07:42:00 +0200
Subject: [PATCH 27/34] spapr: fix core unplug crash
RH-Author: David Gibson <dgibson@redhat.com>
Message-id: <1468309320-14859-28-git-send-email-dgibson@redhat.com>
Patchwork-id: 71147
O-Subject: [RHEL7.3 qemu-kvm-rhev PATCHv2 27/27] spapr: fix core unplug crash
Bugzilla: 1172917
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
From: Greg Kurz <groug@kaod.org>
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: Greg Kurz <groug@kaod.org>
Reviewed-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit 44d691f7d9b6ebab102a31aa87fe59da8f7feff9)
Signed-off-by: David Gibson <dgibson@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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 106557d..733512a 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;
--
1.8.3.1