Re: [PATCH v4 1/2] hw/smbios: add options for type 4 max-speed and current-speed

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 18 Mar 2020 14:48:19 +0800
Heyi Guo <guoheyi@huawei.com> wrote:

> Common VM users sometimes care about CPU speed, so we add two new
> options to allow VM vendors to present CPU speed to their users.
> Normally these information can be fetched from host smbios.
> 
> Strictly speaking, the "max speed" and "current speed" in type 4
> are not really for the max speed and current speed of processor, for
> "max speed" identifies a capability of the system, and "current speed"
> identifies the processor's speed at boot (see smbios spec), but some
> applications do not tell the differences.
> 
> Signed-off-by: Heyi Guo <guoheyi@huawei.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> 
> ---
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> v3 -> v4:
> - Fix the default value when not specifying "-smbios type=4" option;
>   it would be 0 instead of 2000 in previous versions
> - Use uint64_t type to check value overflow
> 
> v2 -> v3:
> - Refine comments per Igor's suggestion.
> 
> v1 -> v2:
> - change "_" in option names to "-"
> - check if option value is too large to fit in SMBIOS type 4 speed
> fields.
> ---
>  hw/smbios/smbios.c | 36 ++++++++++++++++++++++++++++++++----
>  qemu-options.hx    |  3 ++-
>  2 files changed, 34 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> index ffd98727ee..b95de935e8 100644
> --- a/hw/smbios/smbios.c
> +++ b/hw/smbios/smbios.c
> @@ -92,9 +92,21 @@ static struct {
>      const char *manufacturer, *version, *serial, *asset, *sku;
>  } type3;
>  
> +/*
> + * SVVP requires max_speed and current_speed to be set and not being
> + * 0 which counts as unknown (SMBIOS 3.1.0/Table 21). Set the
> + * default value to 2000MHz as we did before.
> + */
> +#define DEFAULT_CPU_SPEED 2000
> +
>  static struct {
>      const char *sock_pfx, *manufacturer, *version, *serial, *asset, *part;
> -} type4;
> +    uint64_t max_speed;
> +    uint64_t current_speed;
> +} type4 = {
> +    .max_speed = DEFAULT_CPU_SPEED,
> +    .current_speed = DEFAULT_CPU_SPEED
> +};
>  
>  static struct {
>      size_t nvalues;
> @@ -272,6 +284,14 @@ static const QemuOptDesc qemu_smbios_type4_opts[] = {
>          .name = "version",
>          .type = QEMU_OPT_STRING,
>          .help = "version number",
> +    },{
> +        .name = "max-speed",
> +        .type = QEMU_OPT_NUMBER,
> +        .help = "max speed in MHz",
> +    },{
> +        .name = "current-speed",
> +        .type = QEMU_OPT_NUMBER,
> +        .help = "speed at system boot in MHz",
>      },{
>          .name = "serial",
>          .type = QEMU_OPT_STRING,
> @@ -586,9 +606,8 @@ static void smbios_build_type_4_table(MachineState *ms, unsigned instance)
>      SMBIOS_TABLE_SET_STR(4, processor_version_str, type4.version);
>      t->voltage = 0;
>      t->external_clock = cpu_to_le16(0); /* Unknown */
> -    /* SVVP requires max_speed and current_speed to not be unknown. */
> -    t->max_speed = cpu_to_le16(2000); /* 2000 MHz */
> -    t->current_speed = cpu_to_le16(2000); /* 2000 MHz */
> +    t->max_speed = cpu_to_le16(type4.max_speed);
> +    t->current_speed = cpu_to_le16(type4.current_speed);
>      t->status = 0x41; /* Socket populated, CPU enabled */
>      t->processor_upgrade = 0x01; /* Other */
>      t->l1_cache_handle = cpu_to_le16(0xFFFF); /* N/A */
> @@ -1129,6 +1148,15 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
>              save_opt(&type4.serial, opts, "serial");
>              save_opt(&type4.asset, opts, "asset");
>              save_opt(&type4.part, opts, "part");
> +            type4.max_speed = qemu_opt_get_number(opts, "max-speed",
> +                                                  DEFAULT_CPU_SPEED);
> +            type4.current_speed = qemu_opt_get_number(opts, "current-speed",
> +                                                      DEFAULT_CPU_SPEED);
> +            if (type4.max_speed > UINT16_MAX ||
> +                type4.current_speed > UINT16_MAX) {
> +                error_setg(errp, "SMBIOS CPU speed is too large (> %d)",
> +                           UINT16_MAX);
> +            }
>              return;
>          case 11:
>              qemu_opts_validate(opts, qemu_smbios_type11_opts, &err);
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 962a5ebaa6..7665addc78 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2277,6 +2277,7 @@ DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
>      "                specify SMBIOS type 3 fields\n"
>      "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n"
>      "              [,asset=str][,part=str]\n"
> +    "              [,max-speed=%d][,current-speed=%d]\n"
>      "                specify SMBIOS type 4 fields\n"
>      "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
>      "               [,asset=str][,part=str][,speed=%d]\n"
> @@ -2298,7 +2299,7 @@ SRST
>  ``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]``
>      Specify SMBIOS type 3 fields
>  
> -``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]``
> +``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,max-speed=%d][,current-speed=%d]``
>      Specify SMBIOS type 4 fields
>  
>  ``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]``