On 07/12/2018 12:01 PM, Greg Kurz wrote: > Recent cleanup in commit a028dd423ee6 dropped the ICPStateClass::reset > handler. It is now up to child ICP classes to call the DeviceClass::reset > handler of the parent class, thanks to device_class_set_parent_reset(). > This is a better object programming pattern,
I think that the device_class_set_parent* routines just obfuscate a little more the object programming approach of QEMU. > but unfortunately it causes QEMU to crash during CPU hotplug: I guess I did not try that :/ Would it be complex to add a spapr unit test for CPU hotplug ? It would be useful. > (qemu) device_add host-spapr-cpu-core,id=core1,core-id=1 > Segmentation fault (core dumped) > > When the hotplug path tries to reset the ICP device, we end up calling: > > static void icp_kvm_reset(DeviceState *dev) > { > ICPStateClass *icpc = ICP_GET_CLASS(dev); > > icpc->parent_reset(dev); > > but icpc->parent_reset is NULL... This happens because icp_kvm_class_init() > calls: > > device_class_set_parent_reset(dc, icp_kvm_reset, > &icpc->parent_reset); > > but dc->reset, ie, DeviceClass::reset for the TYPE_ICP type, is > itself NULL.> > This patch hence sets DeviceClass::reset for the TYPE_ICP type to > point to icp_reset(). It then registers a reset handler that calls > DeviceClass::reset. If the ICP subtype has configured its own reset > handler with device_class_set_parent_reset(), this ensures it will > be called first and it can then call ICPStateClass::parent_reset > safely. This fixes the reset path for the TYPE_KVM_ICP type, which > is the only subtype that defines its own reset function. So, now, isn't ICP reset called twice on KVM ? Anyway, we can sort that out if necessary. Thanks, C. > Reported-by: Satheesh Rajendran <sathn...@linux.vnet.ibm.com> > Suggested-by: David Gibson <da...@gibson.dropbear.id.au> > Fixes: a028dd423ee6dfd091a8c63028240832bf10f671 > Signed-off-by: Greg Kurz <gr...@kaod.org> > --- > hw/intc/xics.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/hw/intc/xics.c b/hw/intc/xics.c > index b9f1a3c97214..c90c893228dc 100644 > --- a/hw/intc/xics.c > +++ b/hw/intc/xics.c > @@ -291,7 +291,7 @@ static const VMStateDescription vmstate_icp_server = { > }, > }; > > -static void icp_reset(void *dev) > +static void icp_reset(DeviceState *dev) > { > ICPState *icp = ICP(dev); > > @@ -303,6 +303,13 @@ static void icp_reset(void *dev) > qemu_set_irq(icp->output, 0); > } > > +static void icp_reset_handler(void *dev) > +{ > + DeviceClass *dc = DEVICE_GET_CLASS(dev); > + > + dc->reset(dev); > +} > + > static void icp_realize(DeviceState *dev, Error **errp) > { > ICPState *icp = ICP(dev); > @@ -345,7 +352,7 @@ static void icp_realize(DeviceState *dev, Error **errp) > return; > } > > - qemu_register_reset(icp_reset, dev); > + qemu_register_reset(icp_reset_handler, dev); > vmstate_register(NULL, icp->cs->cpu_index, &vmstate_icp_server, icp); > } > > @@ -354,7 +361,7 @@ static void icp_unrealize(DeviceState *dev, Error **errp) > ICPState *icp = ICP(dev); > > vmstate_unregister(NULL, &vmstate_icp_server, icp); > - qemu_unregister_reset(icp_reset, dev); > + qemu_unregister_reset(icp_reset_handler, dev); > } > > static void icp_class_init(ObjectClass *klass, void *data) > @@ -363,6 +370,7 @@ static void icp_class_init(ObjectClass *klass, void *data) > > dc->realize = icp_realize; > dc->unrealize = icp_unrealize; > + dc->reset = icp_reset; > } > > static const TypeInfo icp_info = { >