On Mon, 18 Nov 2024 17:10:29 +0100
Igor Mammedov <imamm...@redhat.com> wrote:
> On Tue, 12 Nov 2024 10:17:33 +0800
> Bibo Mao <maob...@loongson.cn> wrote:
>
> > Add topological relationships for Loongarch VCPU and initialize
> > topology member variables. Also physical cpu id calculation
> > method comes from its topo information.
hmm,
maybe split patch on 3 parts,
* initialize topo in possible CPUs
* add topo properties to CPU
* modify main cpu creation loop
(I'd reorder that after 2/6, so you'd have pre_plug handler in
place to move code to)
> >
> > Co-developed-by: Xianglai Li <lixiang...@loongson.cn>
> > Signed-off-by: Bibo Mao <maob...@loongson.cn>
> > ---
> > docs/system/loongarch/virt.rst | 31 +++++++++++++++
> > hw/loongarch/virt.c | 73 ++++++++++++++++++++++++++++------
> > target/loongarch/cpu.c | 12 ++++++
> > target/loongarch/cpu.h | 16 ++++++++
> > 4 files changed, 119 insertions(+), 13 deletions(-)
> >
> > diff --git a/docs/system/loongarch/virt.rst b/docs/system/loongarch/virt.rst
> > index 172fba079e..8daf60785f 100644
> > --- a/docs/system/loongarch/virt.rst
> > +++ b/docs/system/loongarch/virt.rst
> > @@ -28,6 +28,37 @@ The ``qemu-system-loongarch64`` provides emulation for
> > virt
> > machine. You can specify the machine type ``virt`` and
> > cpu type ``la464``.
> >
> > +CPU Topology
> > +------------
> > +
> > +The ``LA464`` type CPUs have the concept of Socket Core and Thread.
> > +
> > +For example:
> > +
> > +``-smp 1,maxcpus=M,sockets=S,cores=C,threads=T``
> > +
> > +The above parameters indicate that the machine has a maximum of ``M``
> > vCPUs and
> > +``S`` sockets, each socket has ``C`` cores, each core has ``T`` threads,
> > +and each thread corresponds to a vCPU.
> > +
> > +Then ``M`` ``S`` ``C`` ``T`` has the following relationship:
> > +
> > +``M = S * C * T``
> > +
> > +In the CPU topology relationship, When we know the ``socket_id``
> > ``core_id``
> > +and ``thread_id`` of the CPU, we can calculate its ``arch_id``:
> > +
> > +``arch_id = (socket_id * S) + (core_id * C) + (thread_id * T)``
>
> Is there a spec or some other reference where all of this is described?
> (or is that a made up just for QEMU?)
>
>
> > +
> > +Similarly, when we know the ``arch_id`` of the CPU,
> > +we can also get its ``socket_id`` ``core_id`` and ``thread_id``:
> > +
> > +``socket_id = arch_id / (C * T)``
> > +
> > +``core_id = (arch_id / T) % C``
> > +
> > +``thread_id = arch_id % T``
> > +
> > Boot options
> > ------------
> >
> > diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c
> > index 9a635d1d3d..1ed5130edf 100644
> > --- a/hw/loongarch/virt.c
> > +++ b/hw/loongarch/virt.c
> > @@ -1143,9 +1143,9 @@ static void virt_init(MachineState *machine)
> > LoongArchVirtMachineState *lvms = LOONGARCH_VIRT_MACHINE(machine);
> > int i;
> > hwaddr base, size, ram_size = machine->ram_size;
> > - const CPUArchIdList *possible_cpus;
> > MachineClass *mc = MACHINE_GET_CLASS(machine);
> > CPUState *cpu;
> > + Object *cpuobj;
> >
> > if (!cpu_model) {
> > cpu_model = LOONGARCH_CPU_TYPE_NAME("la464");
> > @@ -1163,13 +1163,30 @@ static void virt_init(MachineState *machine)
> > memory_region_add_subregion(&lvms->system_iocsr, 0, &lvms->iocsr_mem);
> >
> > /* Init CPUs */
> > - possible_cpus = mc->possible_cpu_arch_ids(machine);
> I'd keep this, and use below, it makes line shorter
>
>
> > - for (i = 0; i < possible_cpus->len; i++) {
> > - cpu = cpu_create(machine->cpu_type);
> > + mc->possible_cpu_arch_ids(machine);
> > + for (i = 0; i < machine->smp.cpus; i++) {
> > + cpuobj = object_new(machine->cpu_type);
> > + if (cpuobj == NULL) {
> > + error_report("Fail to create object with type %s ",
> > + machine->cpu_type);
> > + exit(EXIT_FAILURE);
> > + }
> > +
> > + cpu = CPU(cpuobj);
>
> > cpu->cpu_index = i;
> this probably should be in _pre_plug handler,
> also see
> (a15d2728a9aa pc: Init CPUState->cpu_index with index in possible_cpus[])
> for why x86 does it.
>
> > machine->possible_cpus->cpus[i].cpu = cpu;
> > - lacpu = LOONGARCH_CPU(cpu);
> > + lacpu = LOONGARCH_CPU(cpuobj);
>
> > lacpu->phy_id = machine->possible_cpus->cpus[i].arch_id;
> Given above is derived from topo data set below, I'd move above above
> to pre_plug time, and calculate/set it there based on topo data.
> There is no point in setting both at the same place.
>
> > + object_property_set_int(cpuobj, "socket-id",
> > +
> > machine->possible_cpus->cpus[i].props.socket_id,
> > + NULL);
> > + object_property_set_int(cpuobj, "core-id",
> > +
> > machine->possible_cpus->cpus[i].props.core_id,
> > + NULL);
> > + object_property_set_int(cpuobj, "thread-id",
> > +
> > machine->possible_cpus->cpus[i].props.thread_id,
> > + NULL);
> > + qdev_realize_and_unref(DEVICE(cpuobj), NULL, &error_fatal);
> > }
> > fdt_add_cpu_nodes(lvms);
> > fdt_add_memory_nodes(machine);
> > @@ -1286,6 +1303,35 @@ static void virt_initfn(Object *obj)
> > virt_flash_create(lvms);
> > }
> >
> > +static int virt_get_arch_id_from_topo(MachineState *ms, LoongArchCPUTopo
> > *topo)
> > +{
> > + int arch_id, sock_vcpu_num, core_vcpu_num;
> > +
> > + /*
> > + * calculate total logical cpus across socket/core/thread.
> > + * For more information on how to calculate the arch_id,
> > + * you can refer to the CPU Topology chapter of the
> > + * docs/system/loongarch/virt.rst document.
> > + */
> > + sock_vcpu_num = topo->socket_id * (ms->smp.threads * ms->smp.cores);
> > + core_vcpu_num = topo->core_id * ms->smp.threads;
> > +
> > + /* get vcpu-id(logical cpu index) for this vcpu from this topology */
> > + arch_id = (sock_vcpu_num + core_vcpu_num) + topo->thread_id;
> > +
> > + assert(arch_id >= 0 && arch_id < ms->possible_cpus->len);
> > +
> > + return arch_id;
> > +}
> > +
> > +static void virt_get_topo_from_index(MachineState *ms,
> > + LoongArchCPUTopo *topo, int index)
> > +{
> > + topo->socket_id = index / (ms->smp.cores * ms->smp.threads);
> > + topo->core_id = index / ms->smp.threads % ms->smp.cores;
> > + topo->thread_id = index % ms->smp.threads;
> > +}
> > +
> > static bool memhp_type_supported(DeviceState *dev)
> > {
> > /* we only support pc dimm now */
> > @@ -1385,8 +1431,9 @@ static HotplugHandler
> > *virt_get_hotplug_handler(MachineState *machine,
> >
> > static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
> > {
> > - int n;
> > + int n, arch_id;
> > unsigned int max_cpus = ms->smp.max_cpus;
> > + LoongArchCPUTopo topo;
> >
> > if (ms->possible_cpus) {
> > assert(ms->possible_cpus->len == max_cpus);
> > @@ -1397,17 +1444,17 @@ static const CPUArchIdList
> > *virt_possible_cpu_arch_ids(MachineState *ms)
> > sizeof(CPUArchId) * max_cpus);
> > ms->possible_cpus->len = max_cpus;
> > for (n = 0; n < ms->possible_cpus->len; n++) {
> > + virt_get_topo_from_index(ms, &topo, n);
> > + arch_id = virt_get_arch_id_from_topo(ms, &topo);
> > + ms->possible_cpus->cpus[n].vcpus_count = 1;
> > ms->possible_cpus->cpus[n].type = ms->cpu_type;
> > - ms->possible_cpus->cpus[n].arch_id = n;
> > -
> > + ms->possible_cpus->cpus[n].arch_id = arch_id;
> > ms->possible_cpus->cpus[n].props.has_socket_id = true;
> > - ms->possible_cpus->cpus[n].props.socket_id =
> > - n / (ms->smp.cores * ms->smp.threads);
> > + ms->possible_cpus->cpus[n].props.socket_id = topo.socket_id;
> > ms->possible_cpus->cpus[n].props.has_core_id = true;
> > - ms->possible_cpus->cpus[n].props.core_id =
> > - n / ms->smp.threads % ms->smp.cores;
> > + ms->possible_cpus->cpus[n].props.core_id = topo.core_id;
> > ms->possible_cpus->cpus[n].props.has_thread_id = true;
> > - ms->possible_cpus->cpus[n].props.thread_id = n % ms->smp.threads;
> > + ms->possible_cpus->cpus[n].props.thread_id = topo.thread_id;
> > }
> > return ms->possible_cpus;
> > }
> > diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
> > index 57cc4f314b..a99e22094e 100644
> > --- a/target/loongarch/cpu.c
> > +++ b/target/loongarch/cpu.c
> > @@ -16,6 +16,7 @@
> > #include "kvm/kvm_loongarch.h"
> > #include "exec/exec-all.h"
> > #include "cpu.h"
> > +#include "hw/qdev-properties.h"
> > #include "internals.h"
> > #include "fpu/softfloat-helpers.h"
> > #include "cpu-csr.h"
> > @@ -725,6 +726,7 @@ static void loongarch_cpu_init(Object *obj)
> > timer_init_ns(&cpu->timer, QEMU_CLOCK_VIRTUAL,
> > &loongarch_constant_timer_cb, cpu);
> > #endif
> > + cpu->phy_id = UNSET_PHY_ID;
> > #endif
> > }
> >
> > @@ -823,6 +825,14 @@ static int64_t loongarch_cpu_get_arch_id(CPUState *cs)
> > }
> > #endif
> >
> > +static Property loongarch_cpu_properties[] = {
> > + DEFINE_PROP_INT32("socket-id", LoongArchCPU, socket_id, 0),
> > + DEFINE_PROP_INT32("core-id", LoongArchCPU, core_id, 0),
> > + DEFINE_PROP_INT32("thread-id", LoongArchCPU, thread_id, 0),
> > + DEFINE_PROP_INT32("node-id", LoongArchCPU, node_id,
> > CPU_UNSET_NUMA_NODE_ID),
> > + DEFINE_PROP_END_OF_LIST()
> > +};
> > +
> > static void loongarch_cpu_class_init(ObjectClass *c, void *data)
> > {
> > LoongArchCPUClass *lacc = LOONGARCH_CPU_CLASS(c);
> > @@ -830,6 +840,7 @@ static void loongarch_cpu_class_init(ObjectClass *c,
> > void *data)
> > DeviceClass *dc = DEVICE_CLASS(c);
> > ResettableClass *rc = RESETTABLE_CLASS(c);
> >
> > + device_class_set_props(dc, loongarch_cpu_properties);
> > device_class_set_parent_realize(dc, loongarch_cpu_realizefn,
> > &lacc->parent_realize);
> > resettable_class_set_parent_phases(rc, NULL, loongarch_cpu_reset_hold,
> > NULL,
> > @@ -854,6 +865,7 @@ static void loongarch_cpu_class_init(ObjectClass *c,
> > void *data)
> > #ifdef CONFIG_TCG
> > cc->tcg_ops = &loongarch_tcg_ops;
> > #endif
> > + dc->user_creatable = true;
> > }
> >
> > static const gchar *loongarch32_gdb_arch_name(CPUState *cs)
> > diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
> > index 86c86c6c95..7472df0521 100644
> > --- a/target/loongarch/cpu.h
> > +++ b/target/loongarch/cpu.h
> > @@ -19,6 +19,12 @@
> > #include "cpu-csr.h"
> > #include "cpu-qom.h"
> >
> > +/*
> > + * CPU can't have 0xFFFFFFFF physical ID, use that value to distinguish
> > + * that physical ID hasn't been set yet
>
> pointer to CPU spec/doc here would be nice to have
>
> > + */
> > +#define UNSET_PHY_ID 0xFFFFFFFF
> > +
> > #define IOCSRF_TEMP 0
> > #define IOCSRF_NODECNT 1
> > #define IOCSRF_MSI 2
> > @@ -390,6 +396,12 @@ typedef struct CPUArchState {
> > #endif
> > } CPULoongArchState;
> >
> > +typedef struct LoongArchCPUTopo {
> > + int32_t socket_id; /* socket-id of this VCPU */
> > + int32_t core_id; /* core-id of this VCPU */
> > + int32_t thread_id; /* thread-id of this VCPU */
> > +} LoongArchCPUTopo;
> > +
> > /**
> > * LoongArchCPU:
> > * @env: #CPULoongArchState
> > @@ -404,6 +416,10 @@ struct ArchCPU {
> > uint32_t phy_id;
> > OnOffAuto lbt;
> > OnOffAuto pmu;
> > + int32_t socket_id; /* socket-id of this VCPU */
> > + int32_t core_id; /* core-id of this VCPU */
> > + int32_t thread_id; /* thread-id of this VCPU */
> > + int32_t node_id; /* NUMA node of this VCPU */
> >
> > /* 'compatible' string for this CPU for Linux device trees */
> > const char *dtb_compatible;
>
