Re: [PATCH v3 1/2] hw/i386/pc: Default to use SMBIOS 3.0 for newer machine models

[Michael S. Tsirkin]

On Fri, Jun 02, 2023 at 10:22:54PM -0500, Suravee Suthikulpanit wrote:
> Currently, pc-q35 and pc-i44fx machine models are default to use SMBIOS 2.8
> (32-bit entry point). Since SMBIOS 3.0 (64-bit entry point) is now fully
> supported since QEMU 7.0, default to use SMBIOS 3.0 for newer machine
> models. This is necessary to avoid the following message when launching
> a VM with large number of vcpus.
> 
>    "SMBIOS 2.1 table length 66822 exceeds 65535"
> 
> Note that user can still override the entry point tyme w/ QEMU option
> "-M ..., smbios-entry-point-type=[32|64].
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
>  hw/i386/pc.c         |  5 ++++-
>  hw/i386/pc_piix.c    | 14 ++++++++++++++
>  hw/i386/pc_q35.c     | 14 ++++++++++++++
>  include/hw/i386/pc.h |  2 ++
>  4 files changed, 34 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index bb62c994fa..fced0ab0eb 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1770,7 +1770,10 @@ static void pc_machine_set_smbios_ep(Object *obj, 
> Visitor *v, const char *name,
>  {
>      PCMachineState *pcms = PC_MACHINE(obj);
>  
> -    visit_type_SmbiosEntryPointType(v, name, &pcms->smbios_entry_point_type, 
> errp);
> +    pcms->smbios_use_cmdline_ep_type =
> +        visit_type_SmbiosEntryPointType(v, name,
> +                                        &pcms->smbios_entry_point_type,
> +                                        errp);
>  }
>  
>  static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index d5b0dcd1fe..2905b26666 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -199,6 +199,14 @@ static void pc_init1(MachineState *machine,
>      pc_guest_info_init(pcms);
>  
>      if (pcmc->smbios_defaults) {
> +        /*
> +         * Check if user has specified command line option to override

a command line

> +         * the default SMBIOS default entry point type.

default twice

> +         */
> +        if (!pcms->smbios_use_cmdline_ep_type) {
> +            pcms->smbios_entry_point_type = pcmc->default_smbios_ep_type;
> +        }
> +
>          MachineClass *mc = MACHINE_GET_CLASS(machine);
>          /* These values are guest ABI, do not change */
>          smbios_set_defaults("QEMU", mc->desc,
> @@ -453,6 +461,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pcmc->pci_root_uid = 0;
>      pcmc->default_cpu_version = 1;
> +    pcmc->default_smbios_ep_type = SMBIOS_ENTRY_POINT_TYPE_64;
>  
>      m->family = "pc_piix";
>      m->desc = "Standard PC (i440FX + PIIX, 1996)";
> @@ -476,11 +485,16 @@ DEFINE_I440FX_MACHINE(v8_1, "pc-i440fx-8.1", NULL,
>  
>  static void pc_i440fx_8_0_machine_options(MachineClass *m)
>  {
> +    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_8_1_machine_options(m);
>      m->alias = NULL;
>      m->is_default = false;
>      compat_props_add(m->compat_props, hw_compat_8_0, hw_compat_8_0_len);
>      compat_props_add(m->compat_props, pc_compat_8_0, pc_compat_8_0_len);
> +
> +    /* For pc-i44fx-8.0 and older, use SMBIOS 2.8 by default */
> +    pcmc->default_smbios_ep_type = SMBIOS_ENTRY_POINT_TYPE_32;
>  }
>  
>  DEFINE_I440FX_MACHINE(v8_0, "pc-i440fx-8.0", NULL,
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 6155427e48..2d1bb5fde5 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -199,6 +199,14 @@ static void pc_q35_init(MachineState *machine)
>      pc_guest_info_init(pcms);
>  
>      if (pcmc->smbios_defaults) {
> +        /*
> +         * Check if user has specified command line option to override
> +         * the default SMBIOS default entry point type.

same

> +         */
> +        if (!pcms->smbios_use_cmdline_ep_type) {
> +            pcms->smbios_entry_point_type = pcmc->default_smbios_ep_type;
> +        }
> +
>          /* These values are guest ABI, do not change */
>          smbios_set_defaults("QEMU", mc->desc,
>                              mc->name, pcmc->smbios_legacy_mode,
> @@ -359,6 +367,7 @@ static void pc_q35_machine_options(MachineClass *m)
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pcmc->pci_root_uid = 0;
>      pcmc->default_cpu_version = 1;
> +    pcmc->default_smbios_ep_type = SMBIOS_ENTRY_POINT_TYPE_64;
>  
>      m->family = "pc_q35";
>      m->desc = "Standard PC (Q35 + ICH9, 2009)";
> @@ -387,10 +396,15 @@ DEFINE_Q35_MACHINE(v8_1, "pc-q35-8.1", NULL,
>  
>  static void pc_q35_8_0_machine_options(MachineClass *m)
>  {
> +    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_q35_8_1_machine_options(m);
>      m->alias = NULL;
>      compat_props_add(m->compat_props, hw_compat_8_0, hw_compat_8_0_len);
>      compat_props_add(m->compat_props, pc_compat_8_0, pc_compat_8_0_len);
> +
> +    /* For pc-q35-8.0 and older, use SMBIOS 2.8 by default */
> +    pcmc->default_smbios_ep_type = SMBIOS_ENTRY_POINT_TYPE_32;
>  }
>  
>  DEFINE_Q35_MACHINE(v8_0, "pc-q35-8.0", NULL,
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index c661e9cc80..f754da5a38 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -50,6 +50,7 @@ typedef struct PCMachineState {
>      bool i8042_enabled;
>      bool default_bus_bypass_iommu;
>      uint64_t max_fw_size;
> +    bool smbios_use_cmdline_ep_type;
>  
>      /* ACPI Memory hotplug IO base address */
>      hwaddr memhp_io_base;
> @@ -110,6 +111,7 @@ struct PCMachineClass {
>      bool smbios_defaults;
>      bool smbios_legacy_mode;
>      bool smbios_uuid_encoded;
> +    SmbiosEntryPointType default_smbios_ep_type;
>  
>      /* RAM / address space compat: */
>      bool gigabyte_align;


Can't we avoid this code duplication?

E.g. can't we use the pc_compat_8_0 machinery?

> -- 
> 2.34.1