Commit 2dc6660b authored by Corey Minyard's avatar Corey Minyard Committed by Paolo Bonzini
Browse files

vmstate: Add a VSTRUCT type 



The VMS_STRUCT has no way to specify which version of a structure
to use.  Add a type and a new field to allow the specific version
of a structure to be used.

Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
Message-Id: <1524670052-28373-2-git-send-email-minyard@acm.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8f971cf0

include/migration/vmstate.h

+45 −0
Original line number Diff line number Diff line
@@ -143,6 +143,11 @@ enum VMStateFlags { 
     * to determine the number of entries in the array. Only valid in

     * combination with one of VMS_VARRAY*. */

    VMS_MULTIPLY_ELEMENTS = 0x4000,



    /* A structure field that is like VMS_STRUCT, but uses

     * VMStateField.struct_version_id to tell which version of the

     * structure we are referencing to use. */

    VMS_VSTRUCT           = 0x8000,

};



typedef enum {
@@ -167,6 +172,7 @@ struct VMStateField { 
    enum VMStateFlags flags;

    const VMStateDescription *vmsd;

    int version_id;

    int struct_version_id;

    bool (*field_exists)(void *opaque, int version_id);

};
@@ -248,6 +254,25 @@ extern const VMStateInfo vmstate_info_qtailq; 
    vmstate_offset_array(_state, _field, uint8_t,                    \

                         sizeof(typeof_field(_state, _field)))



/* In the macros below, if there is a _version, that means the macro's

 * field will be processed only if the version being received is >=

 * the _version specified.  In general, if you add a new field, you

 * would increment the structure's version and put that version

 * number into the new field so it would only be processed with the

 * new version.

 *

 * In particular, for VMSTATE_STRUCT() and friends the _version does

 * *NOT* pick the version of the sub-structure.  It works just as

 * specified above.  The version of the top-level structure received

 * is passed down to all sub-structures.  This means that the

 * sub-structures must have version that are compatible with all the

 * structures that use them.

 *

 * If you want to specify the version of the sub-structure, use

 * VMSTATE_VSTRUCT(), which allows the specific sub-structure version

 * to be directly specified.

 */



#define VMSTATE_SINGLE_TEST(_field, _state, _test, _version, _info, _type) { \

    .name         = (stringify(_field)),                             \

    .version_id   = (_version),                                      \
@@ -395,6 +420,17 @@ extern const VMStateInfo vmstate_info_qtailq; 
    .offset     = offsetof(_state, _field),                          \

}



#define VMSTATE_VSTRUCT_TEST(_field, _state, _test, _version, _vmsd, _type, _struct_version) { \

    .name         = (stringify(_field)),                             \

    .version_id   = (_version),                                      \

    .struct_version_id = (_struct_version),                          \

    .field_exists = (_test),                                         \

    .vmsd         = &(_vmsd),                                        \

    .size         = sizeof(_type),                                   \

    .flags        = VMS_VSTRUCT,                                     \

    .offset       = vmstate_offset_value(_state, _field, _type),     \

}



#define VMSTATE_STRUCT_TEST(_field, _state, _test, _version, _vmsd, _type) { \

    .name         = (stringify(_field)),                             \

    .version_id   = (_version),                                      \
@@ -712,6 +748,13 @@ extern const VMStateInfo vmstate_info_qtailq; 
#define VMSTATE_SINGLE(_field, _state, _version, _info, _type)        \

    VMSTATE_SINGLE_TEST(_field, _state, NULL, _version, _info, _type)



#define VMSTATE_VSTRUCT(_field, _state, _vmsd, _type, _struct_version)\

    VMSTATE_VSTRUCT_TEST(_field, _state, NULL, 0, _vmsd, _type, _struct_version)



#define VMSTATE_VSTRUCT_V(_field, _state, _version, _vmsd, _type, _struct_version) \

    VMSTATE_VSTRUCT_TEST(_field, _state, NULL, _version, _vmsd, _type, \

                         _struct_version)



#define VMSTATE_STRUCT(_field, _state, _version, _vmsd, _type)        \

    VMSTATE_STRUCT_TEST(_field, _state, NULL, _version, _vmsd, _type)
@@ -1000,6 +1043,8 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, 
                       void *opaque, int version_id);

int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,

                       void *opaque, QJSON *vmdesc);

int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,

                         void *opaque, QJSON *vmdesc, int version_id);



bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque);

migration/vmstate.c

+21 −4
Original line number Diff line number Diff line
@@ -136,6 +136,9 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, 
                } else if (field->flags & VMS_STRUCT) {

                    ret = vmstate_load_state(f, field->vmsd, curr_elem,

                                             field->vmsd->version_id);

                } else if (field->flags & VMS_VSTRUCT) {

                    ret = vmstate_load_state(f, field->vmsd, curr_elem,

                                             field->struct_version_id);

                } else {

                    ret = field->info->get(f, curr_elem, size, field);

                }
@@ -209,6 +212,8 @@ static const char *vmfield_get_type_name(VMStateField *field) 


    if (field->flags & VMS_STRUCT) {

        type = "struct";

    } else if (field->flags & VMS_VSTRUCT) {

        type = "vstruct";

    } else if (field->info->name) {

        type = field->info->name;

    }
@@ -309,7 +314,13 @@ bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque) 




int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,

                        void *opaque, QJSON *vmdesc)

                       void *opaque, QJSON *vmdesc_id)

{

    return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id);

}



int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,

                         void *opaque, QJSON *vmdesc, int version_id)

{

    int ret = 0;

    VMStateField *field = vmsd->fields;
@@ -327,13 +338,15 @@ int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, 


    if (vmdesc) {

        json_prop_str(vmdesc, "vmsd_name", vmsd->name);

        json_prop_int(vmdesc, "version", vmsd->version_id);

        json_prop_int(vmdesc, "version", version_id);

        json_start_array(vmdesc, "fields");

    }



    while (field->name) {

        if (!field->field_exists ||

            field->field_exists(opaque, vmsd->version_id)) {

        if ((field->field_exists &&

             field->field_exists(opaque, version_id)) ||

            (!field->field_exists &&

             field->version_id <= version_id)) {

            void *first_elem = opaque + field->offset;

            int i, n_elems = vmstate_n_elems(opaque, field);

            int size = vmstate_size(opaque, field);
@@ -363,6 +376,10 @@ int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, 
                } else if (field->flags & VMS_STRUCT) {

                    ret = vmstate_save_state(f, field->vmsd, curr_elem,

                                             vmdesc_loop);

                } else if (field->flags & VMS_VSTRUCT) {

                    ret = vmstate_save_state_v(f, field->vmsd, curr_elem,

                                               vmdesc_loop,

                                               field->struct_version_id);

                } else {

                    ret = field->info->put(f, curr_elem, size, field,

                                     vmdesc_loop);