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Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU |
Date: |
Mon, 15 May 2017 15:16:02 +0200 |
On Mon, 15 May 2017 14:22:32 +0200
Cédric Le Goater <address@hidden> wrote:
> On 05/15/2017 01:40 PM, Greg Kurz wrote:
> > Commit 5bc8d26de20c ("spapr: allocate the ICPState object from under
> > sPAPRCPUCore") moved ICP objects from the machine to CPU cores. This
> > is an improvement since we no longer allocate ICP objects that will
> > never be used. But it has the side-effect of breaking migration of
> > older machine types from older QEMU versions.
> >
> > This patch introduces a compat flag in the sPAPR machine class so
> > that all pseries machine up to 2.9 go on with the previous behavior
> > of pre-allocating ICP objects.
>
> I think this is a quite elegant way to a handle the migration
> regression. Thanks for taking care of it.
>
> Have you tried to simply reparent the ICPs objects to OBJECT(spapr)
> instead of the OBJECT(cpu) ?
>
Do you mean to reparent unconditionally to OBJECT(spapr) for all
machine versions ? I'm not sure this would be beneficial, but I
might be missing something...
> See some minor comments below.
>
> > While here, we also ensure that object_property_add_child() errors cause
> > QEMU to abort for newer machines.
> >
> > Signed-off-by: Greg Kurz <address@hidden>
> > ---
> > hw/ppc/spapr.c | 36 ++++++++++++++++++++++++++++++++++++
> > hw/ppc/spapr_cpu_core.c | 28 ++++++++++++++++++++--------
> > include/hw/ppc/spapr.h | 2 ++
> > 3 files changed, 58 insertions(+), 8 deletions(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index c53989bb10b1..ab3683bcd677 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -126,6 +126,7 @@ error:
> > static void xics_system_init(MachineState *machine, int nr_irqs, Error
> > **errp)
> > {
> > sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
> > + sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
> > Error *local_err = NULL;
> >
> > if (kvm_enabled()) {
> > @@ -151,6 +152,38 @@ static void xics_system_init(MachineState *machine,
> > int nr_irqs, Error **errp)
> > &local_err);
> > }
> >
> > + if (!spapr->ics) {
> > + goto out;
> > + }
> > +
> > + if (smc->must_pre_allocate_icps) {
>
> I am not sure I like 'must', I think 'pre_allocate_icps' should be enough ?
> or simply 'allocate_legacy_icps' ?
>
Ok. I'll go for the latter if it's ok with David.
> > + int smt = kvmppc_smt_threads();
> > + int nr_servers = DIV_ROUND_UP(max_cpus * smt, smp_threads);
>
> may be we should reintroduce nr_servers at the machine level ?
>
I had reintroduced it but then I realized it was only used in this
function.
> > + int i;
> > +
> > + spapr->legacy_icps = g_malloc0(nr_servers * sizeof(ICPState));
> > +
> > + for (i = 0; i < nr_servers; i++) {
> > + void* obj = &spapr->legacy_icps[i];
>
> 'void *'
>
Yeah, patchew already yelled at me :)
> > +
> > + object_initialize(obj, sizeof(ICPState), spapr->icp_type);
> > + object_property_add_child(OBJECT(spapr), "icp[*]", obj,
> > + &error_abort);
>
> David does not like the "icp[*]" syntax.
>
Ah... I wasn't aware of that. But I agree that I should probably create
the object names based on 'i', rather than relying on the more complex
logic in object_property_add().
> > + object_unref(obj);
> > + object_property_add_const_link(obj, "xics", OBJECT(spapr),
> > + &error_abort);
> > + object_property_set_bool(obj, true, "realized", &local_err);
> > + if (local_err) {
> > + while (i--) {
> > + object_unparent(obj);
> > + }
> > + g_free(spapr->legacy_icps);
> > + break;
> > + }
> > + }
> > + }
> > +
> > +out:
> > error_propagate(errp, local_err);
> > }
> >
> > @@ -3256,8 +3289,11 @@ static void
> > spapr_machine_2_9_instance_options(MachineState *machine)
> >
> > static void spapr_machine_2_9_class_options(MachineClass *mc)
> > {
> > + sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
> > +
> > spapr_machine_2_10_class_options(mc);
> > SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_9);
> > + smc->must_pre_allocate_icps = true;
> > }
> >
> > DEFINE_SPAPR_MACHINE(2_9, "2.9", false);
> > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> > index 63d160f7e010..5476647efa06 100644
> > --- a/hw/ppc/spapr_cpu_core.c
> > +++ b/hw/ppc/spapr_cpu_core.c
> > @@ -119,6 +119,7 @@ static void spapr_cpu_core_unrealizefn(DeviceState
> > *dev, Error **errp)
> > size_t size = object_type_get_instance_size(typename);
> > CPUCore *cc = CPU_CORE(dev);
> > int i;
> > + sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> >
> > for (i = 0; i < cc->nr_threads; i++) {
> > void *obj = sc->threads + i * size;
> > @@ -127,7 +128,9 @@ static void spapr_cpu_core_unrealizefn(DeviceState
> > *dev, Error **errp)
> > PowerPCCPU *cpu = POWERPC_CPU(cs);
> >
> > spapr_cpu_destroy(cpu);
> > - object_unparent(cpu->intc);
> > + if (!spapr->legacy_icps) {
> > + object_unparent(cpu->intc);
> > + }
> > cpu_remove_sync(cs);
> > object_unparent(obj);
> > }
> > @@ -142,12 +145,19 @@ static void spapr_cpu_core_realize_child(Object
> > *child, Error **errp)
> > PowerPCCPU *cpu = POWERPC_CPU(cs);
> > Object *obj;
> >
> > - obj = object_new(spapr->icp_type);
> > - object_property_add_child(OBJECT(cpu), "icp", obj, NULL);
> > - object_property_add_const_link(obj, "xics", OBJECT(spapr),
> > &error_abort);
> > - object_property_set_bool(obj, true, "realized", &local_err);
> > - if (local_err) {
> > - goto error;
> > + if (spapr->legacy_icps) {
> > + int index = cpu->parent_obj.cpu_index;
> > +
> > + obj = OBJECT(&spapr->legacy_icps[index]);
> > + } else {
> > + obj = object_new(spapr->icp_type);
> > + object_property_add_child(OBJECT(cpu), "icp", obj, &error_abort);
> > + object_property_add_const_link(obj, "xics", OBJECT(spapr),
> > + &error_abort);
> > + object_property_set_bool(obj, true, "realized", &local_err);
> > + if (local_err) {
> > + goto error;
> > + }
> > }
> >
> > object_property_set_bool(child, true, "realized", &local_err);
> > @@ -164,7 +174,9 @@ static void spapr_cpu_core_realize_child(Object *child,
> > Error **errp)
> > return;
> >
> > error:
> > - object_unparent(obj);
> > + if (!spapr->legacy_icps) {
> > + object_unparent(obj);
> > + }
> > error_propagate(errp, local_err);
> > }
> >
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index 5802f888c39d..72cd5af2679b 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -53,6 +53,7 @@ struct sPAPRMachineClass {
> > bool dr_lmb_enabled; /* enable dynamic-reconfig/hotplug of LMBs
> > */
> > bool use_ohci_by_default; /* use USB-OHCI instead of XHCI */
> > const char *tcg_default_cpu; /* which (TCG) CPU to simulate by default
> > */
> > + bool must_pre_allocate_icps; /* only for pseries-2.9 and older */
> > void (*phb_placement)(sPAPRMachineState *spapr, uint32_t index,
> > uint64_t *buid, hwaddr *pio,
> > hwaddr *mmio32, hwaddr *mmio64,
> > @@ -109,6 +110,7 @@ struct sPAPRMachineState {
> > MemoryHotplugState hotplug_memory;
> >
> > const char *icp_type;
> > + ICPState *legacy_icps;
> > };
> >
> > #define H_SUCCESS 0
> >
>
pgpXqLyYi76VH.pgp
Description: OpenPGP digital signature
[Qemu-devel] [PATCH 5/6] spapr-cpu-core: release ICP object when realization fails, Greg Kurz, 2017/05/15
[Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, Greg Kurz, 2017/05/15
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, Cédric Le Goater, 2017/05/15
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, Greg Kurz, 2017/05/15
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, David Gibson, 2017/05/17
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, Greg Kurz, 2017/05/17
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, David Gibson, 2017/05/19
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, David Gibson, 2017/05/17
Re: [Qemu-devel] [PATCH 6/6] spapr: fix migration of ICP objects from/to older QEMU, David Gibson, 2017/05/17