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 --- migration/vmstate.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) (limited to 'migration/vmstate.c') diff --git a/migration/vmstate.c b/migration/vmstate.c index 7b4bd6e835..2f9d4ba160 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -5,6 +5,7 @@ #include "migration/vmstate.h" #include "qemu/bitops.h" #include "qemu/error-report.h" +#include "qemu/queue.h" #include "trace.h" #include "migration/qjson.h" @@ -965,3 +966,71 @@ const VMStateInfo vmstate_info_bitmap = { .get = get_bitmap, .put = put_bitmap, }; + +/* get for QTAILQ + * meta data about the QTAILQ is encoded in a VMStateField structure + */ +static int get_qtailq(QEMUFile *f, void *pv, size_t unused_size, + VMStateField *field) +{ + int ret = 0; + const VMStateDescription *vmsd = field->vmsd; + /* size of a QTAILQ element */ + size_t size = field->size; + /* offset of the QTAILQ entry in a QTAILQ element */ + size_t entry_offset = field->start; + int version_id = field->version_id; + void *elm; + + trace_get_qtailq(vmsd->name, version_id); + if (version_id > vmsd->version_id) { + error_report("%s %s", vmsd->name, "too new"); + trace_get_qtailq_end(vmsd->name, "too new", -EINVAL); + + return -EINVAL; + } + if (version_id < vmsd->minimum_version_id) { + error_report("%s %s", vmsd->name, "too old"); + trace_get_qtailq_end(vmsd->name, "too old", -EINVAL); + return -EINVAL; + } + + while (qemu_get_byte(f)) { + elm = g_malloc(size); + ret = vmstate_load_state(f, vmsd, elm, version_id); + if (ret) { + return ret; + } + QTAILQ_RAW_INSERT_TAIL(pv, elm, entry_offset); + } + + trace_get_qtailq_end(vmsd->name, "end", ret); + return ret; +} + +/* put for QTAILQ */ +static int put_qtailq(QEMUFile *f, void *pv, size_t unused_size, + VMStateField *field, QJSON *vmdesc) +{ + const VMStateDescription *vmsd = field->vmsd; + /* offset of the QTAILQ entry in a QTAILQ element*/ + size_t entry_offset = field->start; + void *elm; + + trace_put_qtailq(vmsd->name, vmsd->version_id); + + QTAILQ_RAW_FOREACH(elm, pv, entry_offset) { + qemu_put_byte(f, true); + vmstate_save_state(f, vmsd, elm, vmdesc); + } + qemu_put_byte(f, false); + + trace_put_qtailq_end(vmsd->name, "end"); + + return 0; +} +const VMStateInfo vmstate_info_qtailq = { + .name = "qtailq", + .get = get_qtailq, + .put = put_qtailq, +}; -- cgit v1.2.3