On Fri, 12 Apr 2013 09:44:09 -0300 Eduardo Habkost <ehabk...@redhat.com> wrote:
> On Fri, Apr 12, 2013 at 12:01:03PM +0200, Igor Mammedov wrote: > > On Thu, 11 Apr 2013 14:19:37 -0300 > > Eduardo Habkost <ehabk...@redhat.com> wrote: > > > > > On Thu, Apr 11, 2013 at 04:51:57PM +0200, Igor Mammedov wrote: > > > > ... and leave links for not present CPUs empty. > > > > > > > > It will allow users to query for possible APIC IDs and use them > > > > with cpu-add QMP command. > > > > > > > > Signed-off-by: Igor Mammedov <imamm...@redhat.com> > > > > > > I don't see anything wrong with having icc-bridge links as well, but I > > > would really like to have a target-independent namespace with links, > > > that could be used to query for the available/valid CPU IDs for cpu-add > > > commands instead of icc-bridge. The IDs on that namespace could be > > > considered completely opaque. > > > > Considering that -numa in present state is not compatible with cpu-add > > and that all CPU ID in this case are are sequence [0..maxcpus-1], this > > patch could be dropped without any harm. libvirt could just use > > numbers from this sequence like it's doing with current cpu_set without > > any ID discovery. > > But it's not -numa that makes APIC ID probing necessary, it's > non-power-of-2 core/thread counts on -smp (that make APIC IDs not match > CPU indexes). > > "Don't use CPU hotplug with -numa" is easy to be understood by users and > by libvirt, but "don't use CPU hotplug with non-power-of-2 cores/threads > counts" is harder to explain. > > > > > > So, I've postponed target independent until we have -numa reworked, > > then we could have /machine/node/socket/cpu containers with links. > > The problem that needs to be solved, is the links storage ownership. > > Who should allocate and own it? If machine was QOM object already, > > I'd go with machine but it's not yet. > > If we use CPU index as argument to cpu-add, we don't need to handle all > those problems right now, we don't need to expose an APIC ID discovery > interface, we make it work even with non-power-of-2 cores/threads yes, you will get non-power-of-2 working without ID look-up. > counts, and we make it work with -numa. But you won't get this since, only next non-plugged ID will work, due to how cpu_index is allocated. You can't just overwrite it with new value without breaking current code. > > So, my big question is: why are we trying so hard to avoid using CPU > indexes as argument to cpu-add, if it's so much easier, and it is an > obvious solution that makes the interface target-independent without any > extra effort? Using cpu_index instead of APIC ID definitely is not effort free and requires quite a bit of rewrite how its used currently, APIC ID is much much easier and less risky choice in this regard. As for target-independence, any kind of ID is target-independent if treated as opaque. Given that with unplug should come not-contiguous ID usage, the interface to track which CPUs are plugged would be needed anyway. So it could be introduced with this series and provide ID look-up meanwhile. That would give libvirt time actually to start using it, and just remove not-contiguous ID restriction when unplug is ready with all necessary infrastructure already around. > > > > > > > > > > --- > > > > v2: > > > > * s/get_firmware_id/get_arch_id/ due to rebase > > > > * rename cpu_add_notifier to cpu_added_notifier & > > > > icc_bridge_cpu_add_req -> icc_bridge_cpued_add_req > > > > --- > > > > hw/cpu/icc_bus.c | 46 > > > > ++++++++++++++++++++++++++++++++++++++++++++++ > > > > hw/i386/pc.c | 9 +++++++-- include/hw/i386/icc_bus.h | > > > > 2 ++ 3 files changed, 55 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/hw/cpu/icc_bus.c b/hw/cpu/icc_bus.c > > > > index ab9623d..5c0b9d4 100644 > > > > --- a/hw/cpu/icc_bus.c > > > > +++ b/hw/cpu/icc_bus.c > > > > @@ -18,6 +18,7 @@ > > > > */ > > > > #include "hw/i386/icc_bus.h" > > > > #include "hw/sysbus.h" > > > > +#include "sysemu/sysemu.h" > > > > > > > > static void icc_bus_initfn(Object *obj) > > > > { > > > > @@ -61,15 +62,39 @@ typedef struct ICCBridgeState { > > > > SysBusDevice busdev; > > > > MemoryRegion apic_container; > > > > MemoryRegion ioapic_container; > > > > + Notifier cpu_added_notifier; > > > > + Object **links; > > > > } ICCBridgeState; > > > > #define ICC_BRIGDE(obj) OBJECT_CHECK(ICCBridgeState, (obj), > > > > TYPE_ICC_BRIDGE) > > > > > > > > +void icc_bridge_set_cpu_link(Object *bridge, Object *cpu_obj) > > > > +{ > > > > + gchar *name; > > > > + Error *error = NULL; > > > > + CPUState *cpu = CPU(cpu_obj); > > > > + int64_t id = CPU_GET_CLASS(cpu)->get_arch_id(cpu); > > > > + > > > > + name = g_strdup_printf("cpu[%" PRIu32 "]", > > > > x86_cpu_apic_id_from_index(id)); > > > > + object_property_set_link(bridge, cpu_obj, name, &error); > > > > + g_free(name); > > > > + > > > > + g_assert(error == NULL); > > > > +} > > > > + > > > > +static void icc_bridge_cpu_added_req(Notifier *n, void *opaque) > > > > +{ > > > > + ICCBridgeState *s = container_of(n, ICCBridgeState, > > > > cpu_added_notifier); + > > > > + icc_bridge_set_cpu_link(OBJECT(s), OBJECT(opaque)); > > > > +} > > > > + > > > > static void icc_bridge_initfn(Object *obj) > > > > { > > > > ICCBridgeState *s = ICC_BRIGDE(obj); > > > > SysBusDevice *sb = SYS_BUS_DEVICE(obj); > > > > ICCBus *ibus; > > > > + int i; > > > > > > > > ibus = ICC_BUS(qbus_create(TYPE_ICC_BUS, DEVICE(obj), > > > > "icc-bus")); > > > > @@ -85,12 +110,33 @@ static void icc_bridge_initfn(Object *obj) > > > > memory_region_init(&s->ioapic_container, "icc-ioapic-container", > > > > 0x1000); sysbus_init_mmio(sb, &s->ioapic_container); > > > > ibus->ioapic_address_space = &s->ioapic_container; > > > > + > > > > + s->links = g_malloc0(sizeof(Object *) * max_cpus); > > > > + for (i = 0; i < max_cpus; i++) { > > > > + gchar *cpu_name; > > > > + > > > > + cpu_name = g_strdup_printf("cpu[%" PRIu32 "]", > > > > + x86_cpu_apic_id_from_index(i)); > > > > + object_property_add_link(obj, cpu_name, TYPE_CPU, > > > > &s->links[i], NULL); > > > > + g_free(cpu_name); > > > > + } > > > > + > > > > + s->cpu_added_notifier.notify = icc_bridge_cpu_added_req; > > > > + qemu_register_cpu_added_notifier(&s->cpu_added_notifier); > > > > +} > > > > + > > > > +static void icc_bridge_fini(Object *obj) > > > > +{ > > > > + ICCBridgeState *s = ICC_BRIGDE(obj); > > > > + > > > > + g_free(s->links); > > > > } > > > > > > > > static const TypeInfo icc_bridge_info = { > > > > .name = "icc-bridge", > > > > .parent = TYPE_SYS_BUS_DEVICE, > > > > .instance_init = icc_bridge_initfn, > > > > + .instance_finalize = icc_bridge_fini, > > > > .instance_size = sizeof(ICCBridgeState), > > > > }; > > > > > > > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > > > > index 6d5e164..ada235c 100644 > > > > --- a/hw/i386/pc.c > > > > +++ b/hw/i386/pc.c > > > > @@ -870,7 +870,8 @@ void pc_acpi_smi_interrupt(void *opaque, int irq, > > > > int level) } > > > > } > > > > > > > > -static X86CPU *pc_new_cpu(const char *cpu_model, int64_t apic_id, > > > > Error **errp) +static X86CPU *pc_new_cpu(const char *cpu_model, > > > > int64_t apic_id, > > > > + SysBusDevice *icc_bridge, Error **errp) > > > > { > > > > X86CPU *cpu; > > > > > > > > @@ -882,6 +883,10 @@ static X86CPU *pc_new_cpu(const char *cpu_model, > > > > int64_t apic_id, Error **errp) object_property_set_int(OBJECT(cpu), > > > > apic_id, "apic-id", errp); object_property_set_bool(OBJECT(cpu), > > > > true, "realized", errp); > > > > + if (icc_bridge != NULL) { > > > > + icc_bridge_set_cpu_link(OBJECT(icc_bridge), OBJECT(cpu)); > > > > + } > > > > + > > > > if (error_is_set(errp)) { > > > > if (cpu != NULL) { > > > > object_unref(OBJECT(cpu)); > > > > @@ -911,7 +916,7 @@ void pc_cpus_init(const char *cpu_model) > > > > TYPE_ICC_BRIDGE, > > > > NULL)); > > > > for (i = 0; i < smp_cpus; i++) { > > > > - cpu = pc_new_cpu(cpu_model, x86_cpu_apic_id_from_index(i), > > > > &error); > > > > + cpu = pc_new_cpu(cpu_model, x86_cpu_apic_id_from_index(i), > > > > ib, &error); if (error) { > > > > fprintf(stderr, "%s\n", error_get_pretty(error)); > > > > error_free(error); > > > > diff --git a/include/hw/i386/icc_bus.h b/include/hw/i386/icc_bus.h > > > > index 69a0278..bc31cd9 100644 > > > > --- a/include/hw/i386/icc_bus.h > > > > +++ b/include/hw/i386/icc_bus.h > > > > @@ -49,5 +49,7 @@ typedef struct ICCDeviceClass { > > > > > > > > #define TYPE_ICC_BRIDGE "icc-bridge" > > > > > > > > +void icc_bridge_set_cpu_link(Object *bridge, Object *cpu); > > > > + > > > > #endif /* CONFIG_USER_ONLY */ > > > > #endif > > > > -- > > > > 1.8.2 > > > > > > > > > > -- > > > Eduardo > > > > > > -- > > Regards, > > Igor >