Re: [PATCH v2 1/2] hw/smbios: support for type 41 (onboard devices extended information)

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Apr 01, 2021 at 10:25:43AM +0200, Vincent Bernat wrote:
> Type 41 defines the attributes of devices that are onboard. The
> original intent was to imply the BIOS had some level of control over
> the enablement of the associated devices.
> 
> If network devices are present in this table, by default, udev will
> name the corresponding interfaces enoX, X being the instance number.
> Without such information, udev will fallback to using the PCI ID and
> this usually gives ens3 or ens4. This can be a bit annoying as the
> name of the network card may depend on the order of options and may
> change if a new PCI device is added earlier on the commande line.
> Being able to provide SMBIOS type 41 entry ensure the name of the
> interface won't change and helps the user guess the right name without
> booting a first time.
> 
> This can be invoked with:
> 
>     $QEMU -netdev user,id=internet
>           -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet \
>           -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pci=0000:00:09.0
> 
> Which results in the guest seeing dmidecode data and the interface
> exposed as "eno1":
> 
>     $ dmidecode -t 41
>     # dmidecode 3.3
>     Getting SMBIOS data from sysfs.
>     SMBIOS 2.8 present.Handle 0x2900, DMI type 41, 11 bytes
>     Onboard Device
>             Reference Designation: Onboard LAN
>             Type: Ethernet
>             Status: Enabled
>             Type Instance: 1
>             Bus Address: 0000:00:09.0
>     $ udevadm info -p /sys/class/net/eno1 | grep ONBOARD
>     E: ID_NET_NAME_ONBOARD=eno1
>     E: ID_NET_LABEL_ONBOARD=Onboard LAN
> 
> Signed-off-by: Vincent Bernat <vincent@bernat.ch>
> ---
>  hw/smbios/smbios.c           | 119 +++++++++++++++++++++++++++++++++++
>  include/hw/firmware/smbios.h |  11 ++++
>  qemu-options.hx              |   7 ++-
>  3 files changed, 136 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> index f22c4f5b734e..46a08652dff4 100644
> --- a/hw/smbios/smbios.c
> +++ b/hw/smbios/smbios.c


>  static void smbios_register_config(void)
>  {
>      qemu_add_opts(&qemu_smbios_opts);
> @@ -773,6 +826,26 @@ static void smbios_build_type_32_table(void)
>      SMBIOS_BUILD_TABLE_POST;
>  }
>  
> +static void smbios_build_type_41_table(void)
> +{
> +    unsigned instance = 0;
> +    struct type41_instance *t41;
> +
> +    QTAILQ_FOREACH(t41, &type41, next) {
> +        SMBIOS_BUILD_TABLE_PRE(41, 0x2900 + instance, true);
> +
> +        SMBIOS_TABLE_SET_STR(41, reference_designation_str, t41->designation);
> +        t->device_type = t41->kind;
> +        t->device_type_instance = t41->instance;
> +        t->segment_group_number = cpu_to_le16(t41->pci.segment);
> +        t->bus_number = t41->pci.bus;
> +        t->device_number = t41->pci.device;
> +
> +        SMBIOS_BUILD_TABLE_POST;
> +        instance++;
> +    }
> +}
> +
>  static void smbios_build_type_127_table(void)
>  {
>      SMBIOS_BUILD_TABLE_PRE(127, 0x7F00, true); /* required */
> @@ -928,6 +1001,7 @@ void smbios_get_tables(MachineState *ms,
>  
>          smbios_build_type_32_table();
>          smbios_build_type_38_table();
> +        smbios_build_type_41_table();
>          smbios_build_type_127_table();
>  
>          smbios_validate_table(ms);
> @@ -1224,6 +1298,51 @@ void smbios_entry_add(QemuOpts *opts, Error **errp)
>              save_opt(&type17.part, opts, "part");
>              type17.speed = qemu_opt_get_number(opts, "speed", 0);
>              return;
> +        case 41: {
> +            struct type41_instance *t;
> +            Error *local_err = NULL;
> +            int pseg, pbus, pdevice, pfunction;
> +
> +            if (!qemu_opts_validate(opts, qemu_smbios_type41_opts, errp)) {
> +                return;
> +            }
> +            t = calloc(1, sizeof(struct type41_instance));
> +            if (!t) {
> +                error_setg(errp,
> +                           "Unable to allocate memory for a new type 41 instance");
> +                return;
> +            }

QEMU uses GLib allocation functions throughout, which abort
on OOM. So replace this with g_new0.


Regards,
Daniel
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