Re: [Qemu-devel] [PATCH 6/9] pc: acpi: create MADT.lapic entries only for valid lapics

[Eduardo Habkost <ehabkost@redhat.com>]

On Thu, Feb 04, 2016 at 12:47:32PM +0100, Igor Mammedov wrote:
> do not assume that all lapics in range 0..apic_id_limit
> are valid and do not create lapic entries for not
> possible lapics in MADT.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

But there's one minor suggestion below:

> ---
>  hw/i386/acpi-build.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index df13c7d..9eeeffa 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -361,9 +361,11 @@ build_fadt(GArray *table_data, GArray *linker, AcpiPmInfo *pm,
>  }
>  
>  static void
> -build_madt(GArray *table_data, GArray *linker, AcpiCpuInfo *cpu,
> -           PcGuestInfo *guest_info)
> +build_madt(GArray *table_data, GArray *linker,
> +           MachineState *machine, PcGuestInfo *guest_info)
>  {
> +    MachineClass *mc = MACHINE_GET_CLASS(machine);
> +    GArray *apic_id_list = mc->possible_cpu_arch_ids();
>      int madt_start = table_data->len;
>  
>      AcpiMultipleApicTable *madt;
> @@ -376,18 +378,23 @@ build_madt(GArray *table_data, GArray *linker, AcpiCpuInfo *cpu,
>      madt->local_apic_address = cpu_to_le32(APIC_DEFAULT_ADDRESS);
>      madt->flags = cpu_to_le32(1);
>  
> -    for (i = 0; i < guest_info->apic_id_limit; i++) {
> +    for (i = 0; i < apic_id_list->len; i++) {
>          AcpiMadtProcessorApic *apic = acpi_data_push(table_data, sizeof *apic);
> +        CPUArchId id = FETCH_CPU_ARCH_ID(apic_id_list, i);
> +        int apic_id = id.arch_id;
> +
>          apic->type = ACPI_APIC_PROCESSOR;
>          apic->length = sizeof(*apic);
> -        apic->processor_id = i;
> -        apic->local_apic_id = i;
> -        if (test_bit(i, cpu->found_cpus)) {
> +        apic->processor_id = apic_id;
> +        apic->local_apic_id = apic_id;
> +        if (id.cpu != NULL) {

This seems to be the only place where CPUArchId.cpu is being used
(see my previous suggestion about making possible_cpu_arch_ids()
return just an uint64_t list).

Also, using the existing found_cpus bitmap is more efficient than
making multiple calls to qemu_get_cpu_by_arch_id(). I wouldn't
mind keeping the bitmap.

>              apic->flags = cpu_to_le32(1);
>          } else {
>              apic->flags = cpu_to_le32(0);
>          }
>      }
> +    g_array_free(apic_id_list, true);
> +
>      io_apic = acpi_data_push(table_data, sizeof *io_apic);
>      io_apic->type = ACPI_APIC_IO;
>      io_apic->length = sizeof(*io_apic);
> @@ -2659,7 +2666,7 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables)
>      aml_len += tables_blob->len - fadt;
>  
>      acpi_add_table(table_offsets, tables_blob);
> -    build_madt(tables_blob, tables->linker, &cpu, guest_info);
> +    build_madt(tables_blob, tables->linker, machine, guest_info);
>  
>      if (misc.has_hpet) {
>          acpi_add_table(table_offsets, tables_blob);
> -- 
> 1.8.3.1
> 

-- 
Eduardo