From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58355) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3Xe8-0004sr-2z for qemu-devel@nongnu.org; Sat, 14 Oct 2017 21:23:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e3Xe4-0003Nj-N9 for qemu-devel@nongnu.org; Sat, 14 Oct 2017 21:23:16 -0400 Date: Sat, 14 Oct 2017 20:33:37 +1100 From: David Gibson Message-ID: <20171014093337.GG28032@umbus.fritz.box> References: <150789430473.4410.10317971414202753256.stgit@bahia.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="fCcDWlUEdh43YKr8" Content-Disposition: inline In-Reply-To: <150789430473.4410.10317971414202753256.stgit@bahia.lan> Subject: Re: [Qemu-devel] [PATCH] spapr_cpu_core: instantiate CPUs separately List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, Igor Mammedov --fCcDWlUEdh43YKr8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 13, 2017 at 01:31:44PM +0200, Greg Kurz 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. >=20 > Let's allocate all CPUs with object_new() and let QOM frees them > when their reference count reaches zero. This greatly simplify the > code as we don't have to fiddle with the instance size anymore. >=20 > Signed-off-by: Greg Kurz So, I'm pretty sure my first drafts of the core stuff did things this waym and it got nacked, for QOM lifetime reasons that I never really understood. > --- > v2: - mention code simplification in changelog > - use PowerPCCPU * and Object * instead of void * > --- > 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(-) >=20 > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index fd9813bde82f..d9555a3677be 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -3153,12 +3153,10 @@ void spapr_core_release(DeviceState *dev) > =20 > if (smc->pre_2_10_has_unused_icps) { > sPAPRCPUCore *sc =3D SPAPR_CPU_CORE(OBJECT(dev)); > - sPAPRCPUCoreClass *scc =3D SPAPR_CPU_CORE_GET_CLASS(OBJECT(cc)); > - size_t size =3D object_type_get_instance_size(scc->cpu_type); > int i; > =20 > for (i =3D 0; i < cc->nr_threads; i++) { > - CPUState *cs =3D CPU(sc->threads + i * size); > + CPUState *cs =3D CPU(sc->threads[i]); > =20 > pre_2_10_vmstate_register_dummy_icp(cs->cpu_index); > } > @@ -3204,7 +3202,7 @@ static void spapr_core_plug(HotplugHandler *hotplug= _dev, DeviceState *dev, > sPAPRMachineClass *smc =3D SPAPR_MACHINE_CLASS(mc); > sPAPRCPUCore *core =3D SPAPR_CPU_CORE(OBJECT(dev)); > CPUCore *cc =3D CPU_CORE(dev); > - CPUState *cs =3D CPU(core->threads); > + CPUState *cs =3D CPU(core->threads[0]); > sPAPRDRConnector *drc; > Error *local_err =3D NULL; > int smt =3D kvmppc_smt_threads(); > @@ -3249,15 +3247,12 @@ static void spapr_core_plug(HotplugHandler *hotpl= ug_dev, DeviceState *dev, > core_slot->cpu =3D OBJECT(dev); > =20 > if (smc->pre_2_10_has_unused_icps) { > - sPAPRCPUCoreClass *scc =3D SPAPR_CPU_CORE_GET_CLASS(OBJECT(cc)); > - size_t size =3D object_type_get_instance_size(scc->cpu_type); > int i; > =20 > for (i =3D 0; i < cc->nr_threads; i++) { > sPAPRCPUCore *sc =3D SPAPR_CPU_CORE(dev); > - void *obj =3D sc->threads + i * size; > =20 > - cs =3D CPU(obj); > + cs =3D 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_t= ype) > static void spapr_cpu_core_unrealizefn(DeviceState *dev, Error **errp) > { > sPAPRCPUCore *sc =3D SPAPR_CPU_CORE(OBJECT(dev)); > - sPAPRCPUCoreClass *scc =3D SPAPR_CPU_CORE_GET_CLASS(OBJECT(dev)); > - size_t size =3D object_type_get_instance_size(scc->cpu_type); > CPUCore *cc =3D CPU_CORE(dev); > int i; > =20 > for (i =3D 0; i < cc->nr_threads; i++) { > - void *obj =3D sc->threads + i * size; > + Object *obj =3D OBJECT(sc->threads[i]); > DeviceState *dev =3D DEVICE(obj); > CPUState *cs =3D CPU(dev); > PowerPCCPU *cpu =3D POWERPC_CPU(cs); > @@ -146,9 +144,8 @@ static void spapr_cpu_core_realize(DeviceState *dev, = Error **errp) > sPAPRCPUCore *sc =3D SPAPR_CPU_CORE(OBJECT(dev)); > sPAPRCPUCoreClass *scc =3D SPAPR_CPU_CORE_GET_CLASS(OBJECT(dev)); > CPUCore *cc =3D CPU_CORE(OBJECT(dev)); > - size_t size; > Error *local_err =3D NULL; > - void *obj; > + Object *obj; > int i, j; > =20 > if (!spapr) { > @@ -156,18 +153,16 @@ static void spapr_cpu_core_realize(DeviceState *dev= , Error **errp) > return; > } > =20 > - size =3D object_type_get_instance_size(scc->cpu_type); > - sc->threads =3D g_malloc0(size * cc->nr_threads); > + sc->threads =3D g_new(PowerPCCPU *, cc->nr_threads); > for (i =3D 0; i < cc->nr_threads; i++) { > char id[32]; > CPUState *cs; > PowerPCCPU *cpu; > =20 > - obj =3D sc->threads + i * size; > + obj =3D object_new(scc->cpu_type); > =20 > - object_initialize(obj, size, scc->cpu_type); > cs =3D CPU(obj); > - cpu =3D POWERPC_CPU(cs); > + cpu =3D sc->threads[i] =3D POWERPC_CPU(obj); > cs->cpu_index =3D cc->core_id + i; > cpu->vcpu_id =3D (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) > } > =20 > for (j =3D 0; j < cc->nr_threads; j++) { > - obj =3D sc->threads + j * size; > + obj =3D OBJECT(sc->threads[j]); > =20 > 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) > =20 > err: > while (--i >=3D 0) { > - obj =3D sc->threads + i * size; > + obj =3D 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_c= ore.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; > =20 > /*< public >*/ > - void *threads; > + PowerPCCPU **threads; > int node_id; > } sPAPRCPUCore; > =20 >=20 --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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