Re: [Qemu-devel] [PATCH 14/16] pc: Postpone adding ACPI and SMBIOS to fw_cfg

[Corey Minyard]

On 11/14/2013 07:38 AM, Michael S. Tsirkin wrote:
> On Thu, Nov 14, 2013 at 07:28:00AM -0600, Corey Minyard wrote:
>> On 11/14/2013 01:30 AM, Michael S. Tsirkin wrote:
>>> On Tue, Nov 12, 2013 at 10:33:13AM -0600, Corey Minyard wrote:
>>>> Postpone the addition of the ACPI and SMBIOS tables until after
>>>> device initialization.  This allows devices to add entries to these
>>>> tables.
>>>>
>>>> Signed-off-by: Corey Minyard <address@hidden>
>>> Why delay adding FW_CFG_ACPI_TABLES?
>>> These are normally specified by user so they are constant.
>> Because the IPMI device has to dynamically add an entry based on its
>> configuration.
> Where? Which patch does this? It would be a strange thing to do
> because FW_CFG_ACPI_TABLES is normally intended for user-supplied tables
> (though q35 misused it for other purposes).

I don't have that patch out yet.  I had written some code to dynamically
generate ACPI tables, but that was rejected and from what I understand
something was done recently so these tables can be dynamically generated
some other way.  I haven't had time to look into this, but I wanted to
get the main patch set out first.

I know that these tables are generally fixed, but the entry for IPMI
should only be present if the device is specified, and its contents
depend on the configuration supplied,

-corey

>
>> As it is the tables get added to the BIOS access before
>> devices initialize.
>>
>> -corey
>>
>>>> ---
>>>>  hw/i386/pc.c | 38 ++++++++++++++++++++++++++++++--------
>>>>  1 file changed, 30 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>>>> index dee409d..765c95e 100644
>>>> --- a/hw/i386/pc.c
>>>> +++ b/hw/i386/pc.c
>>>> @@ -607,8 +607,6 @@ static unsigned int pc_apic_id_limit(unsigned int 
>>>> max_cpus)
>>>>  static FWCfgState *bochs_bios_init(void)
>>>>  {
>>>>      FWCfgState *fw_cfg;
>>>> -    uint8_t *smbios_table;
>>>> -    size_t smbios_len;
>>>>      uint64_t *numa_fw_cfg;
>>>>      int i, j;
>>>>      unsigned int apic_id_limit = pc_apic_id_limit(max_cpus);
>>>> @@ -631,14 +629,8 @@ static FWCfgState *bochs_bios_init(void)
>>>>      fw_cfg_add_i16(fw_cfg, FW_CFG_MAX_CPUS, (uint16_t)apic_id_limit);
>>>>      fw_cfg_add_i32(fw_cfg, FW_CFG_ID, 1);
>>>>      fw_cfg_add_i64(fw_cfg, FW_CFG_RAM_SIZE, (uint64_t)ram_size);
>>>> -    fw_cfg_add_bytes(fw_cfg, FW_CFG_ACPI_TABLES,
>>>> -                     acpi_tables, acpi_tables_len);
>>>>      fw_cfg_add_i32(fw_cfg, FW_CFG_IRQ0_OVERRIDE, 
>>>> kvm_allows_irq0_override());
>>>>  
>>>> -    smbios_table = smbios_get_table(&smbios_len);
>>>> -    if (smbios_table)
>>>> -        fw_cfg_add_bytes(fw_cfg, FW_CFG_SMBIOS_ENTRIES,
>>>> -                         smbios_table, smbios_len);
>>>>      fw_cfg_add_bytes(fw_cfg, FW_CFG_E820_TABLE,
>>>>                       &e820_table, sizeof(e820_table));
>>>>  
>>>> @@ -1127,6 +1119,31 @@ void pc_acpi_init(const char *default_dsdt)
>>>>      }
>>>>  }
>>>>  
>>>> +struct pc_bios_post_init {
>>>> +    Notifier post_init;
>>>> +    void *fw_cfg;
>>>> +};
>>>> +
>>>> +/* Add the ACPI and SMBIOS tables after all the hardware has been 
>>>> initialized.
>>>> + * This gives devices a chance to add to those tables.
>>>> + */
>>>> +static void pc_bios_post_initfn(Notifier *n, void *opaque)
>>>> +{
>>>> +    struct pc_bios_post_init *p = container_of(n, struct 
>>>> pc_bios_post_init,
>>>> +                                               post_init);
>>>> +    uint8_t *smbios_table;
>>>> +    size_t smbios_len;
>>>> +
>>>> +    fw_cfg_add_bytes(p->fw_cfg, FW_CFG_ACPI_TABLES,
>>>> +                     acpi_tables, acpi_tables_len);
>>>> +    smbios_table = smbios_get_table(&smbios_len);
>>>> +    if (smbios_table)
>>>> +        fw_cfg_add_bytes(p->fw_cfg, FW_CFG_SMBIOS_ENTRIES,
>>>> +                         smbios_table, smbios_len);
>>>> +}
>>>> +
>>>> +static struct pc_bios_post_init post_init;
>>>> +
>>>>  FWCfgState *pc_memory_init(MemoryRegion *system_memory,
>>>>                             const char *kernel_filename,
>>>>                             const char *kernel_cmdline,
>>>> @@ -1196,6 +1213,11 @@ FWCfgState *pc_memory_init(MemoryRegion 
>>>> *system_memory,
>>>>          rom_add_option(option_rom[i].name, option_rom[i].bootindex);
>>>>      }
>>>>      guest_info->fw_cfg = fw_cfg;
>>>> +
>>>> +    post_init.fw_cfg = fw_cfg;
>>>> +    post_init.post_init.notify = pc_bios_post_initfn;
>>>> +    qemu_add_machine_init_done_notifier(&post_init.post_init);
>>>> +
>>>>      return fw_cfg;
>>>>  }
>>>>  
>>>> -- 
>>>> 1.8.3.1