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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: Corey Minyard <cminyard@mvista.com>
Message-Id: <1524670052-28373-2-git-send-email-minyard@acm.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Corey Minyard 2018-04-25 10:27:30 -05:00 committed by Paolo Bonzini
parent 8f971cf0c9
commit 2dc6660bd8
2 changed files with 66 additions and 4 deletions
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45
include/migration/vmstate.h
View File

@ -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);

25
migration/vmstate.c
View File

@ -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);