Commit 32031489 authored by Philippe Mathieu-Daudé's avatar Philippe Mathieu-Daudé
Browse files

hw/nvram/fw_cfg: Add the FW_CFG_DATA_GENERATOR interface 



The FW_CFG_DATA_GENERATOR allows any object to produce
blob of data consumable by the fw_cfg device.

Reviewed-by: default avatarLaszlo Ersek <lersek@redhat.com>
Signed-off-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: default avatarDaniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200623172726.21040-3-philmd@redhat.com>
parent 993aec27

docs/specs/fw_cfg.txt

+8 −1
Original line number Diff line number Diff line
@@ -219,7 +219,7 @@ To check the result, read the "control" field: 


= Externally Provided Items =



As of v2.4, "file" fw_cfg items (i.e., items with selector keys above

Since v2.4, "file" fw_cfg items (i.e., items with selector keys above

FW_CFG_FILE_FIRST, and with a corresponding entry in the fw_cfg file

directory structure) may be inserted via the QEMU command line, using

the following syntax:
@@ -230,6 +230,13 @@ Or 


    -fw_cfg [name=]<item_name>,string=<string>



Since v5.1, QEMU allows some objects to generate fw_cfg-specific content,

the content is then associated with a "file" item using the 'gen_id' option

in the command line, using the following syntax:



    -object <generator-type>,id=<generated_id>,[generator-specific-options] \

    -fw_cfg [name=]<item_name>,gen_id=<generated_id>



See QEMU man page for more documentation.



Using item_name with plain ASCII characters only is recommended.

hw/nvram/fw_cfg.c

+35 −0
Original line number Diff line number Diff line
@@ -1032,6 +1032,35 @@ void *fw_cfg_modify_file(FWCfgState *s, const char *filename, 
    return NULL;

}



void fw_cfg_add_from_generator(FWCfgState *s, const char *filename,

                               const char *gen_id, Error **errp)

{

    FWCfgDataGeneratorClass *klass;

    Error *local_err = NULL;

    GByteArray *array;

    Object *obj;

    gsize size;



    obj = object_resolve_path_component(object_get_objects_root(), gen_id);

    if (!obj) {

        error_setg(errp, "Cannot find object ID '%s'", gen_id);

        return;

    }

    if (!object_dynamic_cast(obj, TYPE_FW_CFG_DATA_GENERATOR_INTERFACE)) {

        error_setg(errp, "Object ID '%s' is not a '%s' subclass",

                   gen_id, TYPE_FW_CFG_DATA_GENERATOR_INTERFACE);

        return;

    }

    klass = FW_CFG_DATA_GENERATOR_GET_CLASS(obj);

    array = klass->get_data(obj, &local_err);

    if (local_err) {

        error_propagate(errp, local_err);

        return;

    }

    size = array->len;

    fw_cfg_add_file(s, filename, g_byte_array_free(array, TRUE), size);

}



static void fw_cfg_machine_reset(void *opaque)

{

    MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
@@ -1333,12 +1362,18 @@ static const TypeInfo fw_cfg_mem_info = { 
    .class_init    = fw_cfg_mem_class_init,

};



static const TypeInfo fw_cfg_data_generator_interface_info = {

    .parent = TYPE_INTERFACE,

    .name = TYPE_FW_CFG_DATA_GENERATOR_INTERFACE,

    .class_size = sizeof(FWCfgDataGeneratorClass),

};



static void fw_cfg_register_types(void)

{

    type_register_static(&fw_cfg_info);

    type_register_static(&fw_cfg_io_info);

    type_register_static(&fw_cfg_mem_info);

    type_register_static(&fw_cfg_data_generator_interface_info);

}



type_init(fw_cfg_register_types)

include/hw/nvram/fw_cfg.h

+43 −0
Original line number Diff line number Diff line
@@ -9,11 +9,36 @@ 
#define TYPE_FW_CFG     "fw_cfg"

#define TYPE_FW_CFG_IO  "fw_cfg_io"

#define TYPE_FW_CFG_MEM "fw_cfg_mem"

#define TYPE_FW_CFG_DATA_GENERATOR_INTERFACE "fw_cfg-data-generator"



#define FW_CFG(obj)     OBJECT_CHECK(FWCfgState,    (obj), TYPE_FW_CFG)

#define FW_CFG_IO(obj)  OBJECT_CHECK(FWCfgIoState,  (obj), TYPE_FW_CFG_IO)

#define FW_CFG_MEM(obj) OBJECT_CHECK(FWCfgMemState, (obj), TYPE_FW_CFG_MEM)



#define FW_CFG_DATA_GENERATOR_CLASS(class) \

    OBJECT_CLASS_CHECK(FWCfgDataGeneratorClass, (class), \

                       TYPE_FW_CFG_DATA_GENERATOR_INTERFACE)

#define FW_CFG_DATA_GENERATOR_GET_CLASS(obj) \

    OBJECT_GET_CLASS(FWCfgDataGeneratorClass, (obj), \

                     TYPE_FW_CFG_DATA_GENERATOR_INTERFACE)



typedef struct FWCfgDataGeneratorClass {

    /*< private >*/

    InterfaceClass parent_class;

    /*< public >*/



    /**

     * get_data:

     * @obj: the object implementing this interface

     * @errp: pointer to a NULL-initialized error object

     *

     * Returns: reference to a byte array containing the data.

     * The caller should release the reference when no longer

     * required.

     */

    GByteArray *(*get_data)(Object *obj, Error **errp);

} FWCfgDataGeneratorClass;



typedef struct fw_cfg_file FWCfgFile;



#define FW_CFG_ORDER_OVERRIDE_VGA    70
@@ -263,6 +288,24 @@ void fw_cfg_add_file_callback(FWCfgState *s, const char *filename, 
void *fw_cfg_modify_file(FWCfgState *s, const char *filename, void *data,

                         size_t len);



/**

 * fw_cfg_add_from_generator:

 * @s: fw_cfg device being modified

 * @filename: name of new fw_cfg file item

 * @gen_id: name of object implementing FW_CFG_DATA_GENERATOR interface

 * @errp: pointer to a NULL initialized error object

 *

 * Add a new NAMED fw_cfg item with the content generated from the

 * @gen_id object. The data generated by the @gen_id object is copied

 * into the data structure of the fw_cfg device.

 * The next available (unused) selector key starting at FW_CFG_FILE_FIRST

 * will be used; also, a new entry will be added to the file directory

 * structure residing at key value FW_CFG_FILE_DIR, containing the item name,

 * data size, and assigned selector key value.

 */

void fw_cfg_add_from_generator(FWCfgState *s, const char *filename,

                               const char *gen_id, Error **errp);



FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,

                                AddressSpace *dma_as);

FWCfgState *fw_cfg_init_io(uint32_t iobase);