From 2dc6660bd8db0bfab0be91135cb0f6d83940d190 Mon Sep 17 00:00:00 2001 From: Corey Minyard Date: Wed, 25 Apr 2018 10:27:30 -0500 Subject: [PATCH] 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 Message-Id: <1524670052-28373-2-git-send-email-minyard@acm.org> Signed-off-by: Paolo Bonzini --- include/migration/vmstate.h | 45 +++++++++++++++++++++++++++++++++++++ migration/vmstate.c | 25 +++++++++++++++++---- 2 files changed, 66 insertions(+), 4 deletions(-) diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h index df463fd33d..efa0a1150e 100644 --- a/include/migration/vmstate.h +++ b/include/migration/vmstate.h @@ -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); diff --git a/migration/vmstate.c b/migration/vmstate.c index 0b3282c9df..f0b07f4ea1 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -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);