From: David Gibson <david@gibson.dropbear.id.au>
To: Igor Mammedov <imammedo@redhat.com>
Cc: Greg Kurz <groug@kaod.org>, qemu-devel@nongnu.org, qemu-ppc@nongnu.org
Subject: Re: [Qemu-devel] [PATCH for-2.12 REPOST] spapr_cpu_core: instantiate CPUs separately
Date: Tue, 21 Nov 2017 11:14:06 +1100 [thread overview]
Message-ID: <20171121001406.GO19214@umbus.fritz.box> (raw)
In-Reply-To: <20171120155648.21bcbe5b@redhat.com>
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On Mon, Nov 20, 2017 at 03:56:48PM +0100, Igor Mammedov wrote:
> On Mon, 20 Nov 2017 10:19:54 +0100
> Greg Kurz <groug@kaod.org> wrote:
>
> > The current code assumes that only the CPU core object holds a
> > reference on each individual CPU object, and happily frees their
> > allocated memory when the core is unrealized. This is dangerous
> > as some other code can legitimely keep a pointer to a CPU if it
> > calls object_ref(), but it would end up with a dangling pointer.
> >
> > Let's allocate all CPUs with object_new() and let QOM frees them
> s/frees/free/
>
> > when their reference count reaches zero. This greatly simplify the
> > code as we don't have to fiddle with the instance size anymore.
> >
> > Signed-off-by: Greg Kurz <groug@kaod.org>
> Acked-by: Igor Mammedov <imammedo@redhat.com>
Applied to ppc-for-2.12 with the typo above fixed.
>
> > ---
> > hw/ppc/spapr.c | 11 +++--------
> > hw/ppc/spapr_cpu_core.c | 19 +++++++------------
> > include/hw/ppc/spapr_cpu_core.h | 2 +-
> > 3 files changed, 11 insertions(+), 21 deletions(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 174e7ff0678d..fc92b9d914a5 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -3173,12 +3173,10 @@ void spapr_core_release(DeviceState *dev)
> >
> > if (smc->pre_2_10_has_unused_icps) {
> > sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev));
> > - sPAPRCPUCoreClass *scc = SPAPR_CPU_CORE_GET_CLASS(OBJECT(cc));
> > - size_t size = object_type_get_instance_size(scc->cpu_type);
> > int i;
> >
> > for (i = 0; i < cc->nr_threads; i++) {
> > - CPUState *cs = CPU(sc->threads + i * size);
> > + CPUState *cs = CPU(sc->threads[i]);
> >
> > pre_2_10_vmstate_register_dummy_icp(cs->cpu_index);
> > }
> > @@ -3224,7 +3222,7 @@ static void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
> > sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev));
> > CPUCore *cc = CPU_CORE(dev);
> > - CPUState *cs = CPU(core->threads);
> > + CPUState *cs = CPU(core->threads[0]);
> > sPAPRDRConnector *drc;
> > Error *local_err = NULL;
> > int smt = kvmppc_smt_threads();
> > @@ -3269,15 +3267,12 @@ static void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > core_slot->cpu = OBJECT(dev);
> >
> > if (smc->pre_2_10_has_unused_icps) {
> > - sPAPRCPUCoreClass *scc = SPAPR_CPU_CORE_GET_CLASS(OBJECT(cc));
> > - size_t size = object_type_get_instance_size(scc->cpu_type);
> > int i;
> >
> > for (i = 0; i < cc->nr_threads; i++) {
> > sPAPRCPUCore *sc = SPAPR_CPU_CORE(dev);
> > - void *obj = sc->threads + i * size;
> >
> > - cs = CPU(obj);
> > + cs = CPU(sc->threads[i]);
> > pre_2_10_vmstate_unregister_dummy_icp(cs->cpu_index);
> > }
> > }
> > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> > index 3a4c17401226..588f9b45714a 100644
> > --- a/hw/ppc/spapr_cpu_core.c
> > +++ b/hw/ppc/spapr_cpu_core.c
> > @@ -79,13 +79,11 @@ const char *spapr_get_cpu_core_type(const char *cpu_type)
> > static void spapr_cpu_core_unrealizefn(DeviceState *dev, Error **errp)
> > {
> > sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev));
> > - sPAPRCPUCoreClass *scc = SPAPR_CPU_CORE_GET_CLASS(OBJECT(dev));
> > - size_t size = object_type_get_instance_size(scc->cpu_type);
> > CPUCore *cc = CPU_CORE(dev);
> > int i;
> >
> > for (i = 0; i < cc->nr_threads; i++) {
> > - void *obj = sc->threads + i * size;
> > + Object *obj = OBJECT(sc->threads[i]);
> > DeviceState *dev = DEVICE(obj);
> > CPUState *cs = CPU(dev);
> > PowerPCCPU *cpu = POWERPC_CPU(cs);
> > @@ -146,9 +144,8 @@ static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
> > sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev));
> > sPAPRCPUCoreClass *scc = SPAPR_CPU_CORE_GET_CLASS(OBJECT(dev));
> > CPUCore *cc = CPU_CORE(OBJECT(dev));
> > - size_t size;
> > Error *local_err = NULL;
> > - void *obj;
> > + Object *obj;
> > int i, j;
> >
> > if (!spapr) {
> > @@ -156,18 +153,16 @@ static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
> > return;
> > }
> >
> > - size = object_type_get_instance_size(scc->cpu_type);
> > - sc->threads = g_malloc0(size * cc->nr_threads);
> > + sc->threads = g_new(PowerPCCPU *, cc->nr_threads);
> > for (i = 0; i < cc->nr_threads; i++) {
> > char id[32];
> > CPUState *cs;
> > PowerPCCPU *cpu;
> >
> > - obj = sc->threads + i * size;
> > + obj = object_new(scc->cpu_type);
> >
> > - object_initialize(obj, size, scc->cpu_type);
> > cs = CPU(obj);
> > - cpu = POWERPC_CPU(cs);
> > + cpu = sc->threads[i] = POWERPC_CPU(obj);
> > cs->cpu_index = cc->core_id + i;
> > cpu->vcpu_id = (cc->core_id * spapr->vsmt / smp_threads) + i;
> > if (kvm_enabled() && !kvm_vcpu_id_is_valid(cpu->vcpu_id)) {
> > @@ -192,7 +187,7 @@ static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
> > }
> >
> > for (j = 0; j < cc->nr_threads; j++) {
> > - obj = sc->threads + j * size;
> > + obj = OBJECT(sc->threads[j]);
> >
> > spapr_cpu_core_realize_child(obj, spapr, &local_err);
> > if (local_err) {
> > @@ -203,7 +198,7 @@ static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
> >
> > err:
> > while (--i >= 0) {
> > - obj = sc->threads + i * size;
> > + obj = OBJECT(sc->threads[i]);
> > object_unparent(obj);
> > }
> > g_free(sc->threads);
> > diff --git a/include/hw/ppc/spapr_cpu_core.h b/include/hw/ppc/spapr_cpu_core.h
> > index f2d48d6a6786..1129f344aa0c 100644
> > --- a/include/hw/ppc/spapr_cpu_core.h
> > +++ b/include/hw/ppc/spapr_cpu_core.h
> > @@ -28,7 +28,7 @@ typedef struct sPAPRCPUCore {
> > CPUCore parent_obj;
> >
> > /*< public >*/
> > - void *threads;
> > + PowerPCCPU **threads;
> > int node_id;
> > } sPAPRCPUCore;
> >
> >
> >
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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prev parent reply other threads:[~2017-11-21 0:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-20 9:19 [Qemu-devel] [PATCH for-2.12 REPOST] spapr_cpu_core: instantiate CPUs separately Greg Kurz
2017-11-20 14:56 ` Igor Mammedov
2017-11-21 0:14 ` David Gibson [this message]
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