From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50057) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bLDTj-0006lr-Nm for qemu-devel@nongnu.org; Thu, 07 Jul 2016 13:52:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bLDTe-00021V-NU for qemu-devel@nongnu.org; Thu, 07 Jul 2016 13:52:46 -0400 Received: from 9.mo69.mail-out.ovh.net ([46.105.56.78]:35789) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bLDTe-00021I-Bm for qemu-devel@nongnu.org; Thu, 07 Jul 2016 13:52:42 -0400 Received: from player779.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo69.mail-out.ovh.net (Postfix) with ESMTP id 620041010F60 for ; Thu, 7 Jul 2016 19:52:41 +0200 (CEST) Date: Thu, 7 Jul 2016 19:52:32 +0200 From: Greg Kurz Message-ID: <20160707195232.6347b8ed@bahia.lan> In-Reply-To: <1467903025-13383-3-git-send-email-bharata@linux.vnet.ibm.com> References: <1467903025-13383-1-git-send-email-bharata@linux.vnet.ibm.com> <1467903025-13383-3-git-send-email-bharata@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v2 2/5] cpu: Introduce CPUState::stable_cpu_id List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bharata B Rao Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, david@gibson.dropbear.id.au, imammedo@redhat.com, nikunj@linux.vnet.ibm.com, pbonzini@redhat.com On Thu, 7 Jul 2016 20:20:22 +0530 Bharata B Rao wrote: > Add CPUState::stable_cpu_id and use that as instance_id in > vmstate_register() call. > > Introduce has-stable_cpu_id property that allows target machines to > optionally switch to using stable_cpu_id instead of cpu_index. If stable_cpu_id is in the [0..max_vcpus) range, then it does not really depend on the machine type or version. In this case, the property is not needed. > This will help allow successful migration in cases where holes are > introduced in cpu_index range after CPU hot removals. > > Suggested-by: Igor Mammedov > Signed-off-by: Bharata B Rao > --- > exec.c | 6 ++++-- > include/qom/cpu.h | 5 +++++ > qom/cpu.c | 6 ++++++ > 3 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/exec.c b/exec.c > index fb73910..3b36fe5 100644 > --- a/exec.c > +++ b/exec.c > @@ -619,12 +619,14 @@ static void cpu_release_index(CPUState *cpu) > void cpu_vmstate_register(CPUState *cpu) > { > CPUClass *cc = CPU_GET_CLASS(cpu); > + int instance_id = cpu->has_stable_cpu_id ? cpu->stable_cpu_id : > + cpu->cpu_index; > > if (qdev_get_vmsd(DEVICE(cpu)) == NULL) { > - vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu); > + vmstate_register(NULL, instance_id, &vmstate_cpu_common, cpu); > } > if (cc->vmsd != NULL) { > - vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu); > + vmstate_register(NULL, instance_id, cc->vmsd, cpu); > } > } > > diff --git a/include/qom/cpu.h b/include/qom/cpu.h > index 331386f..527c021 100644 > --- a/include/qom/cpu.h > +++ b/include/qom/cpu.h > @@ -273,6 +273,9 @@ struct qemu_work_item { > * @kvm_fd: vCPU file descriptor for KVM. > * @work_mutex: Lock to prevent multiple access to queued_work_*. > * @queued_work_first: First asynchronous work pending. > + * @stable_cpu_id: Use as instance_id argument in cpu vmstate_register calls > + * @has_stable_cpu_id: Set to enforce the use of @stable_cpu_id > + * over cpu_index during vmstate registration. > * > * State of one CPU core or thread. > */ > @@ -360,6 +363,8 @@ struct CPUState { > (absolute value) offset as small as possible. This reduces code > size, especially for hosts without large memory offsets. */ > uint32_t tcg_exit_req; > + int stable_cpu_id; > + bool has_stable_cpu_id; > }; > > QTAILQ_HEAD(CPUTailQ, CPUState); > diff --git a/qom/cpu.c b/qom/cpu.c > index 1095ea1..bae1bf7 100644 > --- a/qom/cpu.c > +++ b/qom/cpu.c > @@ -363,6 +363,11 @@ static int64_t cpu_common_get_arch_id(CPUState *cpu) > return cpu->cpu_index; > } > > +static Property cpu_common_properties[] = { > + DEFINE_PROP_BOOL("has-stable-cpu-id", CPUState, has_stable_cpu_id, false), > + DEFINE_PROP_END_OF_LIST() > +}; > + > static void cpu_class_init(ObjectClass *klass, void *data) > { > DeviceClass *dc = DEVICE_CLASS(klass); > @@ -394,6 +399,7 @@ static void cpu_class_init(ObjectClass *klass, void *data) > * IRQs, adding reset handlers, halting non-first CPUs, ... > */ > dc->cannot_instantiate_with_device_add_yet = true; > + dc->props = cpu_common_properties; > } > > static const TypeInfo cpu_type_info = {