Hi Bibo,
[snip]
> +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)``
What's the difference between arch_id and CPU index (CPUState.cpu_index)?
> static void virt_init(MachineState *machine)
> {
> - LoongArchCPU *lacpu;
> const char *cpu_model = machine->cpu_type;
> MemoryRegion *address_space_mem = get_system_memory();
> LoongArchVirtMachineState *lvms = LOONGARCH_VIRT_MACHINE(machine);
> @@ -1145,7 +1144,7 @@ static void virt_init(MachineState *machine)
> 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");
> @@ -1164,12 +1163,25 @@ static void virt_init(MachineState *machine)
>
> /* Init CPUs */
> possible_cpus = mc->possible_cpu_arch_ids(machine);
> - for (i = 0; i < possible_cpus->len; i++) {
> - cpu = cpu_create(machine->cpu_type);
> - cpu->cpu_index = i;
> - machine->possible_cpus->cpus[i].cpu = cpu;
> - lacpu = LOONGARCH_CPU(cpu);
> - lacpu->phy_id = machine->possible_cpus->cpus[i].arch_id;
> + for (i = 0; i < machine->smp.cpus; i++) {
> + cpuobj = object_new(machine->cpu_type);
> + object_property_set_uint(cpuobj, "phy-id",
> + possible_cpus->cpus[i].arch_id, NULL);
> + /*
> + * The CPU in place at the time of machine startup will also enter
> + * the CPU hot-plug process when it is created, but at this time,
> + * the GED device has not been created, resulting in exit in the CPU
> + * hot-plug process, which can avoid the incumbent CPU repeatedly
> + * applying for resources.
> + *
> + * The interrupt resource of the in-place CPU will be requested at
> + * the current function call virt_irq_init().
> + *
> + * The interrupt resource of the subsequently inserted CPU will be
> + * requested in the CPU hot-plug process.
> + */
> + qdev_realize(DEVICE(cpuobj), NULL, &error_fatal);
> + object_unref(cpuobj);
You can use qdev_realize_and_unref().
> }
> fdt_add_cpu_nodes(lvms);
> fdt_add_memory_nodes(machine);
> @@ -1286,6 +1298,35 @@ 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;
Looking at the calculations, arch_id looks the same as cpu_index, right?
> + 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 +1426,9 @@ 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 +1439,17 @@ 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 = ms->smp.threads;
In include/hw/boards.h, the doc of CPUArchId said:
vcpus_count - number of threads provided by @cpu object
And I undersatnd each element in possible_cpus->cpus[] is mapped to a
CPU object, so that here vcpus_count should be 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 7212fb5f8f..5dfc0d5c43 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"
> @@ -780,6 +781,15 @@ static int64_t loongarch_cpu_get_arch_id(CPUState *cs)
> }
> #endif
>
> +static Property loongarch_cpu_properties[] = {
> + DEFINE_PROP_UINT32("phy-id", LoongArchCPU, phy_id, UNSET_PHY_ID),
IIUC, the phy_id is kind of like the x86 apic_id, but the field is completely
derived from topology, so why do you need to define it as a property and then
expose it to the user?
Thanks,
Zhao
