From 94869d5c528bf5df54f37cf5390bc979e6ed46fd Mon Sep 17 00:00:00 2001 From: Jianjun Duan Date: Thu, 19 Jan 2017 11:00:51 -0800 Subject: migration: migrate QTAILQ Currently we cannot directly transfer a QTAILQ instance because of the limitation in the migration code. Here we introduce an approach to transfer such structures. We created VMStateInfo vmstate_info_qtailq for QTAILQ. Similar VMStateInfo can be created for other data structures such as list. When a QTAILQ is migrated from source to target, it is appended to the corresponding QTAILQ structure, which is assumed to have been properly initialized. This approach will be used to transfer pending_events and ccs_list in spapr state. We also create some macros in qemu/queue.h to access a QTAILQ using pointer arithmetic. This ensures that we do not depend on the implementation details about QTAILQ in the migration code. Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Jianjun Duan Message-Id: <1484852453-12728-3-git-send-email-duanj@linux.vnet.ibm.com> Signed-off-by: Dr. David Alan Gilbert --- include/migration/vmstate.h | 20 +++++++++++++++ include/qemu/queue.h | 60 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) (limited to 'include') diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h index 7e61b1e..3bbe3ed 100644 --- a/include/migration/vmstate.h +++ b/include/migration/vmstate.h @@ -260,6 +260,7 @@ extern const VMStateInfo vmstate_info_timer; extern const VMStateInfo vmstate_info_buffer; extern const VMStateInfo vmstate_info_unused_buffer; extern const VMStateInfo vmstate_info_bitmap; +extern const VMStateInfo vmstate_info_qtailq; #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0) #define type_check_array(t1,t2,n) ((t1(*)[n])0 - (t2*)0) @@ -671,6 +672,25 @@ extern const VMStateInfo vmstate_info_bitmap; .offset = offsetof(_state, _field), \ } +/* For migrating a QTAILQ. + * Target QTAILQ needs be properly initialized. + * _type: type of QTAILQ element + * _next: name of QTAILQ entry field in QTAILQ element + * _vmsd: VMSD for QTAILQ element + * size: size of QTAILQ element + * start: offset of QTAILQ entry in QTAILQ element + */ +#define VMSTATE_QTAILQ_V(_field, _state, _version, _vmsd, _type, _next) \ +{ \ + .name = (stringify(_field)), \ + .version_id = (_version), \ + .vmsd = &(_vmsd), \ + .size = sizeof(_type), \ + .info = &vmstate_info_qtailq, \ + .offset = offsetof(_state, _field), \ + .start = offsetof(_type, _next), \ +} + /* _f : field name _f_n : num of elements field_name _n : num of elements diff --git a/include/qemu/queue.h b/include/qemu/queue.h index 342073f..35292c3 100644 --- a/include/qemu/queue.h +++ b/include/qemu/queue.h @@ -438,4 +438,64 @@ struct { \ #define QTAILQ_PREV(elm, headname, field) \ (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) +#define field_at_offset(base, offset, type) \ + ((type) (((char *) (base)) + (offset))) + +typedef struct DUMMY_Q_ENTRY DUMMY_Q_ENTRY; +typedef struct DUMMY_Q DUMMY_Q; + +struct DUMMY_Q_ENTRY { + QTAILQ_ENTRY(DUMMY_Q_ENTRY) next; +}; + +struct DUMMY_Q { + QTAILQ_HEAD(DUMMY_Q_HEAD, DUMMY_Q_ENTRY) head; +}; + +#define dummy_q ((DUMMY_Q *) 0) +#define dummy_qe ((DUMMY_Q_ENTRY *) 0) + +/* + * Offsets of layout of a tail queue head. + */ +#define QTAILQ_FIRST_OFFSET (offsetof(typeof(dummy_q->head), tqh_first)) +#define QTAILQ_LAST_OFFSET (offsetof(typeof(dummy_q->head), tqh_last)) +/* + * Raw access of elements of a tail queue + */ +#define QTAILQ_RAW_FIRST(head) \ + (*field_at_offset(head, QTAILQ_FIRST_OFFSET, void **)) +#define QTAILQ_RAW_TQH_LAST(head) \ + (*field_at_offset(head, QTAILQ_LAST_OFFSET, void ***)) + +/* + * Offsets of layout of a tail queue element. + */ +#define QTAILQ_NEXT_OFFSET (offsetof(typeof(dummy_qe->next), tqe_next)) +#define QTAILQ_PREV_OFFSET (offsetof(typeof(dummy_qe->next), tqe_prev)) + +/* + * Raw access of elements of a tail entry + */ +#define QTAILQ_RAW_NEXT(elm, entry) \ + (*field_at_offset(elm, entry + QTAILQ_NEXT_OFFSET, void **)) +#define QTAILQ_RAW_TQE_PREV(elm, entry) \ + (*field_at_offset(elm, entry + QTAILQ_PREV_OFFSET, void ***)) +/* + * Tail queue tranversal using pointer arithmetic. + */ +#define QTAILQ_RAW_FOREACH(elm, head, entry) \ + for ((elm) = QTAILQ_RAW_FIRST(head); \ + (elm); \ + (elm) = QTAILQ_RAW_NEXT(elm, entry)) +/* + * Tail queue insertion using pointer arithmetic. + */ +#define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do { \ + QTAILQ_RAW_NEXT(elm, entry) = NULL; \ + QTAILQ_RAW_TQE_PREV(elm, entry) = QTAILQ_RAW_TQH_LAST(head); \ + *QTAILQ_RAW_TQH_LAST(head) = (elm); \ + QTAILQ_RAW_TQH_LAST(head) = &QTAILQ_RAW_NEXT(elm, entry); \ +} while (/*CONSTCOND*/0) + #endif /* QEMU_SYS_QUEUE_H */ -- cgit v1.1