Re: [Qemu-devel] [PATCH v3 07/19] pc: set APIC ID based on socket/core/thread ids if it's not been set yet

[Bandan Das]

Igor Mammedov <address@hidden> writes:

> CPU added with device_add help won't have APIC ID set,
> so set it according to socket/core/thread ids provided
> with device_add command.
>
> Signed-off-by: Igor Mammedov <address@hidden>
> ---
> v3:
>  - use %u for printing topo ids
> v2:
>  - add validity checks for socket-id/core-id/thread-id values
> ---
>  hw/i386/pc.c | 44 +++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 41 insertions(+), 3 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 24231ca..29da2d4 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1763,14 +1763,52 @@ static void pc_cpu_pre_plug(HotplugHandler 
> *hotplug_dev,
>                              DeviceState *dev, Error **errp)
>  {
>      int idx;
> +    CPUArchId *cpu_slot;
>      X86CPUTopoInfo topo;
>      X86CPU *cpu = X86_CPU(dev);
>      PCMachineState *pcms = PC_MACHINE(hotplug_dev);
> -    CPUArchId *cpu_slot = pc_find_cpu_slot(pcms, CPU(dev), &idx);
>  
> +    /* if APIC ID is not set, set it based on socket/core/thread properties 
> */
> +    if (cpu->apic_id == UNASSIGNED_APIC_ID) {
> +        int max_socket = (max_cpus - 1) / smp_threads / smp_cores;
> +
> +        if (cpu->socket_id < 0) {
> +            error_setg(errp, "CPU socket-id is not set");
> +            return;
> +        } else if (cpu->socket_id > max_socket) {
> +            error_setg(errp, "Invalid CPU socket-id: %u must be in range 
> 0:%u",
> +                       cpu->socket_id, max_socket);
> +            return;
> +        }
> +        if (cpu->core_id < 0) {
> +            error_setg(errp, "CPU core-id is not set");
> +            return;
> +        } else if (cpu->core_id > (smp_cores - 1)) {
> +            error_setg(errp, "Invalid CPU core-id: %u must be in range 0:%u",
> +                       cpu->core_id, smp_cores - 1);
> +            return;
> +        }
> +        if (cpu->thread_id < 0) {
> +            error_setg(errp, "CPU thread-id is not set");
> +            return;
> +        } else if (cpu->thread_id > (smp_threads - 1)) {
> +            error_setg(errp, "Invalid CPU thread-id: %u must be in range 
> 0:%u",
> +                       cpu->thread_id, smp_threads - 1);
> +            return;
> +        }

Just curoious, when any of these values < 0, the only other values that they
can take is -1, right ? I am wondering why decided to do the check differently
for in the preceeding patch.

Bandan
> +        topo.pkg_id = cpu->socket_id;
> +        topo.core_id = cpu->core_id;
> +        topo.smt_id = cpu->thread_id;
> +        cpu->apic_id = apicid_from_topo_ids(smp_cores, smp_threads, &topo);
> +    }
> +
> +    cpu_slot = pc_find_cpu_slot(pcms, CPU(dev), &idx);
>      if (!cpu_slot) {
> -        error_setg(errp, "Invalid CPU index with APIC ID (%" PRIu32
> -                   "), valid range 0:%d", cpu->apic_id,
> +        x86_topo_ids_from_apicid(cpu->apic_id, smp_cores, smp_threads, 
> &topo);
> +        error_setg(errp, "Invalid CPU[socket: %d, core: %d, thread: %d] with"
> +                  " APIC ID (%" PRIu32 "), valid index range 0:%d",
> +                   topo.pkg_id, topo.core_id, topo.smt_id, cpu->apic_id,
>                     pcms->possible_cpus->len - 1);
>          return;
>      }