Re: [PATCH v2] hw/smbios: add options for type 4 max-speed and current-speed

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 2 Mar 2020 17:29:10 +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>

With comment fixed as suggested below:
  Reviewed-by: Igor Mammedov <imammedo@redhat.com>

PS:
pls add/extend test cases for these options (default and custom settings).
(see test_smbios_structs() for example)
I'd do it as an additional patch.


> ---
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> 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 | 28 +++++++++++++++++++++++++---
>  qemu-options.hx    |  3 ++-
>  2 files changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> index ffd98727ee..77135a1eca 100644
> --- a/hw/smbios/smbios.c
> +++ b/hw/smbios/smbios.c
> @@ -94,6 +94,8 @@ static struct {
>  
>  static struct {
>      const char *sock_pfx, *manufacturer, *version, *serial, *asset, *part;
> +    uint32_t max_speed;
> +    uint32_t current_speed;
>  } type4;
>  
>  static struct {
> @@ -272,6 +274,14 @@ 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 +596,8 @@ 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 +1138,19 @@ 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");
> +            /*
> +             * SVVP requires max_speed and current_speed to not be unknown, and
double negation is hard to read, so

s/
to not be unknown
/
to be set and not being 0 which counts as unknown (SMBIOS 3.1.0/Table 21)
/

> +             * we set the default value to 2000MHz as we did before.
s/,and we set/. Set/

> +             */
> +            type4.max_speed = qemu_opt_get_number(opts, "max-speed", 2000);
> +            type4.current_speed = qemu_opt_get_number(opts, "current-speed",
> +                                                      2000);
> +            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 ac315c1ac4..7a2f7c1f66 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2233,6 +2233,7 @@ 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"
> @@ -2255,7 +2256,7 @@ Specify SMBIOS type 2 fields
>  @item -smbios type=3[,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,sku=@var{str}]
>  Specify SMBIOS type 3 fields
>  
> -@item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}]
> +@item -smbios type=4[,sock_pfx=@var{str}][,manufacturer=@var{str}][,version=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}][,max-speed=@var{%d}][,current-speed=@var{%d}]
>  Specify SMBIOS type 4 fields
>  
>  @item -smbios type=17[,loc_pfx=@var{str}][,bank=@var{str}][,manufacturer=@var{str}][,serial=@var{str}][,asset=@var{str}][,part=@var{str}][,speed=@var{%d}]