diff options
| -rw-r--r-- | include/migration/vmstate.h | 19 | ||||
| -rw-r--r-- | migration/vmstate.c | 40 |
2 files changed, 59 insertions, 0 deletions
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h index 7339594337..63e7b02e05 100644 --- a/include/migration/vmstate.h +++ b/include/migration/vmstate.h @@ -259,6 +259,7 @@ extern const VMStateInfo vmstate_info_cpudouble; extern const VMStateInfo vmstate_info_timer; extern const VMStateInfo vmstate_info_buffer; extern const VMStateInfo vmstate_info_unused_buffer; +extern const VMStateInfo vmstate_info_tmp; extern const VMStateInfo vmstate_info_bitmap; extern const VMStateInfo vmstate_info_qtailq; @@ -649,6 +650,24 @@ extern const VMStateInfo vmstate_info_qtailq; .offset = offsetof(_state, _field), \ } +/* Allocate a temporary of type 'tmp_type', set tmp->parent to _state + * and execute the vmsd on the temporary. Note that we're working with + * the whole of _state here, not a field within it. + * We compile time check that: + * That _tmp_type contains a 'parent' member that's a pointer to the + * '_state' type + * That the pointer is right at the start of _tmp_type. + */ +#define VMSTATE_WITH_TMP(_state, _tmp_type, _vmsd) { \ + .name = "tmp", \ + .size = sizeof(_tmp_type) + \ + QEMU_BUILD_BUG_ON_ZERO(offsetof(_tmp_type, parent) != 0) + \ + type_check_pointer(_state, \ + typeof_field(_tmp_type, parent)), \ + .vmsd = &(_vmsd), \ + .info = &vmstate_info_tmp, \ +} + #define VMSTATE_UNUSED_BUFFER(_test, _version, _size) { \ .name = "unused", \ .field_exists = (_test), \ diff --git a/migration/vmstate.c b/migration/vmstate.c index 520341a2de..b4d8ae982a 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -935,6 +935,46 @@ const VMStateInfo vmstate_info_unused_buffer = { .put = put_unused_buffer, }; +/* vmstate_info_tmp, see VMSTATE_WITH_TMP, the idea is that we allocate + * a temporary buffer and the pre_load/pre_save methods in the child vmsd + * copy stuff from the parent into the child and do calculations to fill + * in fields that don't really exist in the parent but need to be in the + * stream. + */ +static int get_tmp(QEMUFile *f, void *pv, size_t size, VMStateField *field) +{ + int ret; + const VMStateDescription *vmsd = field->vmsd; + int version_id = field->version_id; + void *tmp = g_malloc(size); + + /* Writes the parent field which is at the start of the tmp */ + *(void **)tmp = pv; + ret = vmstate_load_state(f, vmsd, tmp, version_id); + g_free(tmp); + return ret; +} + +static int put_tmp(QEMUFile *f, void *pv, size_t size, VMStateField *field, + QJSON *vmdesc) +{ + const VMStateDescription *vmsd = field->vmsd; + void *tmp = g_malloc(size); + + /* Writes the parent field which is at the start of the tmp */ + *(void **)tmp = pv; + vmstate_save_state(f, vmsd, tmp, vmdesc); + g_free(tmp); + + return 0; +} + +const VMStateInfo vmstate_info_tmp = { + .name = "tmp", + .get = get_tmp, + .put = put_tmp, +}; + /* bitmaps (as defined by bitmap.h). Note that size here is the size * of the bitmap in bits. The on-the-wire format of a bitmap is 64 * bit words with the bits in big endian order. The in-memory format |