Re: [Qemu-devel] [PATCH for-2.1 2/2] i386/acpi-build: support hotplug of VCPU with APIC ID 0xFF

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Mar 14, 2014 at 11:22:52PM +0100, Laszlo Ersek wrote:
> Building on the previous patch, raise the maximal count of processor
> objects / NTFY branches / CPON elements from 255 to 256. This allows the
> VCPU with APIC ID 0xFF to be hotplugged.
> 
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  hw/i386/acpi-build.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 2bbefb5..51162fc 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -999,11 +999,15 @@ build_ssdt(GArray *table_data, GArray *linker,
>             AcpiCpuInfo *cpu, AcpiPmInfo *pm, AcpiMiscInfo *misc,
>             PcPciInfo *pci, PcGuestInfo *guest_info)
>  {
> -    int acpi_cpus = MIN(0xff, guest_info->apic_id_limit);

Maybe just make this line
     int acpi_cpus = guest_info->apic_id_limit;
and then the patch will be smaller.

>      int ssdt_start = table_data->len;
>      uint8_t *ssdt_ptr;
>      int i;
>  
> +    /* The current AML generator can cover the APIC ID range [0..255],
> +     * inclusive, for VCPU hotplug. */
> +    QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
> +    g_assert(guest_info->apic_id_limit <= ACPI_CPU_HOTPLUG_ID_LIMIT);
> +
>      /* Copy header and patch values in the S3_ / S4_ / S5_ packages */
>      ssdt_ptr = acpi_data_push(table_data, sizeof(ssdp_misc_aml));
>      memcpy(ssdt_ptr, ssdp_misc_aml, sizeof(ssdp_misc_aml));
> @@ -1029,7 +1033,7 @@ build_ssdt(GArray *table_data, GArray *linker,
>          build_append_nameseg(sb_scope, "_SB_");
>  
>          /* build Processor object for each processor */
> -        for (i = 0; i < acpi_cpus; i++) {
> +        for (i = 0; i < guest_info->apic_id_limit; i++) {
>              uint8_t *proc = acpi_data_push(sb_scope, ACPI_PROC_SIZEOF);
>              memcpy(proc, ACPI_PROC_AML, ACPI_PROC_SIZEOF);
>              proc[ACPI_PROC_OFFSET_CPUHEX] = acpi_get_hex(i >> 4);
> @@ -1042,7 +1046,8 @@ build_ssdt(GArray *table_data, GArray *linker,
>           *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
>           */
>          /* Arg0 = Processor ID = APIC ID */
> -        build_append_notify_method(sb_scope, "NTFY", "CP%0.02X", acpi_cpus);
> +        build_append_notify_method(sb_scope, "NTFY", "CP%0.02X",
> +                                   guest_info->apic_id_limit);
>  
>          /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })" */
>          build_append_byte(sb_scope, 0x08); /* NameOp */
> @@ -1052,8 +1057,9 @@ build_ssdt(GArray *table_data, GArray *linker,
>              GArray *package = build_alloc_array();
>              uint8_t op = 0x13; /* VarPackageOp */
>  
> -            build_append_int(package, acpi_cpus); /* VarNumElements */
> -            for (i = 0; i < acpi_cpus; i++) {
> +            build_append_int(package,
> +                             guest_info->apic_id_limit); /* VarNumElements */
> +            for (i = 0; i < guest_info->apic_id_limit; i++) {
>                  uint8_t b = test_bit(i, cpu->found_cpus) ? 0x01 : 0x00;
>                  build_append_byte(package, b);
>              }
> -- 
> 1.8.3.1