[PATCH] migration: Support QLIST migration

[Eric Auger <eric.auger@redhat.com>]

94869d5c52 ("migration: migrate QTAILQ") introduced support
for QTAILQ migration. Let's do the same for QLIST.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 include/migration/vmstate.h |  21 ++++++
 include/qemu/queue.h        |  30 ++++++++
 migration/vmstate-types.c   |  60 ++++++++++++++++
 tests/test-vmstate.c        | 133 ++++++++++++++++++++++++++++++++++++
 4 files changed, 244 insertions(+)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 1fbfd099dd..54ec9caeb0 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -224,6 +224,7 @@ 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;
+extern const VMStateInfo vmstate_info_qlist;
 
 #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0)
 /*
@@ -754,6 +755,26 @@ extern const VMStateInfo vmstate_info_qtailq;
     .start        = offsetof(_type, _next),                              \
 }
 
+/*
+ * For migrating a QLIST
+ * Target QLIST needs be properly initialized.
+ * _type: type of QLIST element
+ * _next: name of QLIST_ENTRY entry field in QLIST element
+ * _vmsd: VMSD for QLIST element
+ * size: size of QLIST element
+ * start: offset of QLIST_ENTRY in QTAILQ element
+ */
+#define VMSTATE_QLIST_V(_field, _state, _version, _vmsd, _type, _next)  \
+{                                                                        \
+    .name         = (stringify(_field)),                                 \
+    .version_id   = (_version),                                          \
+    .vmsd         = &(_vmsd),                                            \
+    .size         = sizeof(_type),                                       \
+    .info         = &vmstate_info_qlist,                                 \
+    .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 73bf4a984d..e965b4d18d 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -491,4 +491,34 @@ union {                                                                 \
         QTAILQ_RAW_TQH_CIRC(head)->tql_prev = QTAILQ_RAW_TQE_CIRC(elm, entry);  \
 } while (/*CONSTCOND*/0)
 
+#define QLIST_RAW_FIRST(head)                                                  \
+        field_at_offset(head, 0, void *)
+
+#define QLIST_RAW_NEXT(elm, entry)                                             \
+        field_at_offset(elm, entry, void *)
+
+#define QLIST_RAW_PREVIOUS(elm, entry)                                         \
+        field_at_offset(elm, entry + sizeof(void *), void *)
+
+#define QLIST_RAW_FOREACH(elm, head, entry)                                    \
+        for ((elm) = *QLIST_RAW_FIRST(head);                                   \
+             (elm);                                                            \
+             (elm) = *QLIST_RAW_NEXT(elm, entry))
+
+#define QLIST_RAW_INSERT_TAIL(head, elm, entry) do {                           \
+        void *iter, *last = NULL;                                              \
+        *QLIST_RAW_NEXT(elm, entry) = NULL;                                    \
+        if (!*QLIST_RAW_FIRST(head)) {                                         \
+            *QLIST_RAW_FIRST(head) = elm;                                      \
+            *QLIST_RAW_PREVIOUS(elm, entry) = head;                            \
+            break;                                                             \
+        }                                                                      \
+        for (iter = *QLIST_RAW_FIRST(head);                                    \
+             iter; last = iter, iter = *QLIST_RAW_NEXT(iter, entry))           \
+            { }                                                                \
+        *QLIST_RAW_NEXT(last, entry) = elm;                                    \
+        *QLIST_RAW_PREVIOUS(elm, entry) = last;                                \
+} while (0)
+
+
 #endif /* QEMU_SYS_QUEUE_H */
diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
index bee658a1b2..0eedc614f1 100644
--- a/migration/vmstate-types.c
+++ b/migration/vmstate-types.c
@@ -691,3 +691,63 @@ const VMStateInfo vmstate_info_qtailq = {
     .get  = get_qtailq,
     .put  = put_qtailq,
 };
+
+static int put_qlist(QEMUFile *f, void *pv, size_t unused_size,
+                     const 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;
+    int ret;
+
+    QLIST_RAW_FOREACH(elm, pv, entry_offset) {
+        qemu_put_byte(f, true);
+        ret = vmstate_save_state(f, vmsd, elm, vmdesc);
+        if (ret) {
+            return ret;
+        }
+    }
+    qemu_put_byte(f, false);
+
+    return 0;
+}
+
+static int get_qlist(QEMUFile *f, void *pv, size_t unused_size,
+                     const VMStateField *field)
+{
+    int ret = 0;
+    const VMStateDescription *vmsd = field->vmsd;
+    /* size of a QLIST element */
+    size_t size = field->size;
+    /* offset of the QLIST entry in a QLIST element */
+    size_t entry_offset = field->start;
+    int version_id = field->version_id;
+    void *elm;
+
+    if (version_id > vmsd->version_id) {
+        error_report("%s %s",  vmsd->name, "too new");
+        return -EINVAL;
+    }
+    if (version_id < vmsd->minimum_version_id) {
+        error_report("%s %s",  vmsd->name, "too old");
+        return -EINVAL;
+    }
+
+    while (qemu_get_byte(f)) {
+        elm = g_malloc(size);
+        ret = vmstate_load_state(f, vmsd, elm, version_id);
+        if (ret) {
+            return ret;
+        }
+        QLIST_RAW_INSERT_TAIL(pv, elm, entry_offset);
+    }
+
+    return ret;
+}
+
+const VMStateInfo vmstate_info_qlist = {
+    .name = "qlist",
+    .get  = get_qlist,
+    .put  = put_qlist,
+};
diff --git a/tests/test-vmstate.c b/tests/test-vmstate.c
index e80c4c6143..017eab4c8a 100644
--- a/tests/test-vmstate.c
+++ b/tests/test-vmstate.c
@@ -812,6 +812,137 @@ static void test_load_q(void)
     qemu_fclose(fload);
 }
 
+/* test QLIST Migration */
+
+typedef struct TestQListElement {
+    uint32_t  id;
+    QLIST_ENTRY(TestQListElement) next;
+} TestQListElement;
+
+typedef struct TestQListContainer {
+    uint32_t  id;
+    QLIST_HEAD(, TestQListElement) list;
+} TestQListContainer;
+
+static const VMStateDescription vmstate_qlist_element = {
+    .name = "test/queue list",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(id, TestQListElement),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_container = {
+    .name = "test/container/qlist",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(id, TestQListContainer),
+        VMSTATE_QLIST_V(list, TestQListContainer, 1, vmstate_qlist_element,
+                        TestQListElement, next),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static uint8_t qlist_dump[] = {
+    0x00, 0x00, 0x00, 0x01, /* container id */
+    0x1, /* start of a */
+    0x00, 0x00, 0x00, 0x0a,
+    0x1, /* start of b */
+    0x00, 0x00, 0x0b, 0x00,
+    0x1, /* start of c */
+    0x00, 0x0c, 0x00, 0x00,
+    0x1, /* start of d */
+    0x0d, 0x00, 0x00, 0x00,
+    0x0, /* end of list */
+    QEMU_VM_EOF, /* just to ensure we won't get EOF reported prematurely */
+};
+
+static TestQListContainer *alloc_container(void)
+{
+    TestQListElement *a = g_malloc(sizeof(TestQListElement));
+    TestQListElement *b = g_malloc(sizeof(TestQListElement));
+    TestQListElement *c = g_malloc(sizeof(TestQListElement));
+    TestQListElement *d = g_malloc(sizeof(TestQListElement));
+    TestQListContainer *container = g_malloc(sizeof(TestQListContainer));
+
+    a->id = 0x0a;
+    b->id = 0x0b00;
+    c->id = 0xc0000;
+    d->id = 0xd000000;
+    container->id = 1;
+
+    QLIST_INIT(&container->list);
+    QLIST_INSERT_HEAD(&container->list, d, next);
+    QLIST_INSERT_HEAD(&container->list, c, next);
+    QLIST_INSERT_HEAD(&container->list, b, next);
+    QLIST_INSERT_HEAD(&container->list, a, next);
+    return container;
+}
+
+static void free_container(TestQListContainer *container)
+{
+    TestQListElement *iter, *tmp;
+
+    QLIST_FOREACH_SAFE(iter, &container->list, next, tmp) {
+        QLIST_REMOVE(iter, next);
+        g_free(iter);
+    }
+    g_free(container);
+}
+
+static void compare_containers(TestQListContainer *c1, TestQListContainer *c2)
+{
+    TestQListElement *first_item_c1, *first_item_c2;
+
+    while (!QLIST_EMPTY(&c1->list)) {
+        first_item_c1 = QLIST_FIRST(&c1->list);
+        first_item_c2 = QLIST_FIRST(&c2->list);
+        assert(first_item_c2);
+        assert(first_item_c1->id == first_item_c2->id);
+        QLIST_REMOVE(first_item_c1, next);
+        QLIST_REMOVE(first_item_c2, next);
+        g_free(first_item_c1);
+        g_free(first_item_c2);
+    }
+    assert(QLIST_EMPTY(&c2->list));
+}
+
+static void test_save_qlist(void)
+{
+    TestQListContainer *container = alloc_container();
+
+    save_vmstate(&vmstate_container, container);
+    compare_vmstate(qlist_dump, sizeof(qlist_dump));
+    free_container(container);
+}
+
+static void test_load_qlist(void)
+{
+    QEMUFile *fsave, *fload;
+    TestQListContainer *orig_container = alloc_container();
+    TestQListContainer *dest_container = g_malloc0(sizeof(TestQListContainer));
+    char eof;
+
+    QLIST_INIT(&dest_container->list);
+
+    fsave = open_test_file(true);
+    qemu_put_buffer(fsave, qlist_dump, sizeof(qlist_dump));
+    g_assert(!qemu_file_get_error(fsave));
+    qemu_fclose(fsave);
+
+    fload = open_test_file(false);
+    vmstate_load_state(fload, &vmstate_container, dest_container, 1);
+    eof = qemu_get_byte(fload);
+    g_assert(!qemu_file_get_error(fload));
+    g_assert_cmpint(eof, ==, QEMU_VM_EOF);
+    compare_containers(orig_container, dest_container);
+    free_container(orig_container);
+    free_container(dest_container);
+}
+
 typedef struct TmpTestStruct {
     TestStruct *parent;
     int64_t diff;
@@ -932,6 +1063,8 @@ int main(int argc, char **argv)
                     test_arr_ptr_prim_0_load);
     g_test_add_func("/vmstate/qtailq/save/saveq", test_save_q);
     g_test_add_func("/vmstate/qtailq/load/loadq", test_load_q);
+    g_test_add_func("/vmstate/qlist/save/saveqlist", test_save_qlist);
+    g_test_add_func("/vmstate/qlist/load/loadqlist", test_load_qlist);
     g_test_add_func("/vmstate/tmp_struct", test_tmp_struct);
     g_test_run();
 
-- 
2.20.1