X-Git-Url: https://repo.jachan.dev/qemu.git/blobdiff_plain/1393a48526078cda985759c459de9bc803e0e4fe..dd4339c540285b3a0904c631f8174a59d04be767:/migration/vmstate.c

diff --git a/migration/vmstate.c b/migration/vmstate.c
index bf3d5db301..7b4a607c51 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -5,8 +5,9 @@
 #include "migration/vmstate.h"
 #include "qemu/bitops.h"
 #include "qemu/error-report.h"
+#include "qemu/queue.h"
 #include "trace.h"
-#include "qjson.h"
+#include "migration/qjson.h"
 
 static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
                                     void *opaque, QJSON *vmdesc);
@@ -33,6 +34,7 @@ static int vmstate_n_elems(void *opaque, VMStateField *field)
         n_elems *= field->num;
     }
 
+    trace_vmstate_n_elems(field->name, n_elems);
     return n_elems;
 }
 
@@ -50,29 +52,15 @@ static int vmstate_size(void *opaque, VMStateField *field)
     return size;
 }
 
-static void *vmstate_base_addr(void *opaque, VMStateField *field, bool alloc)
+static void vmstate_handle_alloc(void *ptr, VMStateField *field, void *opaque)
 {
-    void *base_addr = opaque + field->offset;
-
-    if (field->flags & VMS_POINTER) {
-        if (alloc && (field->flags & VMS_ALLOC)) {
-            gsize size = 0;
-            if (field->flags & VMS_VBUFFER) {
-                size = vmstate_size(opaque, field);
-            } else {
-                int n_elems = vmstate_n_elems(opaque, field);
-                if (n_elems) {
-                    size = n_elems * field->size;
-                }
-            }
-            if (size) {
-                *((void **)base_addr + field->start) = g_malloc(size);
-            }
+    if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) {
+        gsize size = vmstate_size(opaque, field);
+        size *= vmstate_n_elems(opaque, field);
+        if (size) {
+            *(void **)ptr = g_malloc(size);
         }
-        base_addr = *(void **)base_addr + field->start;
     }
-
-    return base_addr;
 }
 
 int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
@@ -83,6 +71,9 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
 
     trace_vmstate_load_state(vmsd->name, version_id);
     if (version_id > vmsd->version_id) {
+        error_report("%s: incoming version_id %d is too new "
+                     "for local version_id %d",
+                     vmsd->name, version_id, vmsd->version_id);
         trace_vmstate_load_state_end(vmsd->name, "too new", -EINVAL);
         return -EINVAL;
     }
@@ -93,6 +84,9 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
             trace_vmstate_load_state_end(vmsd->name, "old path", ret);
             return ret;
         }
+        error_report("%s: incoming version_id %d is too old "
+                     "for local minimum version_id  %d",
+                     vmsd->name, version_id, vmsd->minimum_version_id);
         trace_vmstate_load_state_end(vmsd->name, "too old", -EINVAL);
         return -EINVAL;
     }
@@ -108,28 +102,38 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
              field->field_exists(opaque, version_id)) ||
             (!field->field_exists &&
              field->version_id <= version_id)) {
-            void *base_addr = vmstate_base_addr(opaque, field, true);
+            void *first_elem = opaque + field->offset;
             int i, n_elems = vmstate_n_elems(opaque, field);
             int size = vmstate_size(opaque, field);
 
+            vmstate_handle_alloc(first_elem, field, opaque);
+            if (field->flags & VMS_POINTER) {
+                first_elem = *(void **)first_elem;
+                assert(first_elem || !n_elems || !size);
+            }
             for (i = 0; i < n_elems; i++) {
-                void *addr = base_addr + size * i;
+                void *curr_elem = first_elem + size * i;
 
                 if (field->flags & VMS_ARRAY_OF_POINTER) {
-                    addr = *(void **)addr;
+                    curr_elem = *(void **)curr_elem;
                 }
-                if (field->flags & VMS_STRUCT) {
-                    ret = vmstate_load_state(f, field->vmsd, addr,
+                if (!curr_elem && size) {
+                    /* if null pointer check placeholder and do not follow */
+                    assert(field->flags & VMS_ARRAY_OF_POINTER);
+                    ret = vmstate_info_nullptr.get(f, curr_elem, size, NULL);
+                } else if (field->flags & VMS_STRUCT) {
+                    ret = vmstate_load_state(f, field->vmsd, curr_elem,
                                              field->vmsd->version_id);
                 } else {
-                    ret = field->info->get(f, addr, size);
-
+                    ret = field->info->get(f, curr_elem, size, field);
                 }
                 if (ret >= 0) {
                     ret = qemu_file_get_error(f);
                 }
                 if (ret < 0) {
                     qemu_file_set_error(f, ret);
+                    error_report("Failed to load %s:%s", vmsd->name,
+                                 field->name);
                     trace_vmstate_load_field_error(field->name, ret);
                     return ret;
                 }
@@ -297,6 +301,8 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
 {
     VMStateField *field = vmsd->fields;
 
+    trace_vmstate_save_state_top(vmsd->name);
+
     if (vmsd->pre_save) {
         vmsd->pre_save(opaque);
     }
@@ -310,25 +316,34 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
     while (field->name) {
         if (!field->field_exists ||
             field->field_exists(opaque, vmsd->version_id)) {
-            void *base_addr = vmstate_base_addr(opaque, field, false);
+            void *first_elem = opaque + field->offset;
             int i, n_elems = vmstate_n_elems(opaque, field);
             int size = vmstate_size(opaque, field);
             int64_t old_offset, written_bytes;
             QJSON *vmdesc_loop = vmdesc;
 
+            trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems);
+            if (field->flags & VMS_POINTER) {
+                first_elem = *(void **)first_elem;
+                assert(first_elem || !n_elems || !size);
+            }
             for (i = 0; i < n_elems; i++) {
-                void *addr = base_addr + size * i;
+                void *curr_elem = first_elem + size * i;
 
                 vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems);
                 old_offset = qemu_ftell_fast(f);
-
                 if (field->flags & VMS_ARRAY_OF_POINTER) {
-                    addr = *(void **)addr;
+                    assert(curr_elem);
+                    curr_elem = *(void **)curr_elem;
                 }
-                if (field->flags & VMS_STRUCT) {
-                    vmstate_save_state(f, field->vmsd, addr, vmdesc_loop);
+                if (!curr_elem && size) {
+                    /* if null pointer write placeholder and do not follow */
+                    assert(field->flags & VMS_ARRAY_OF_POINTER);
+                    vmstate_info_nullptr.put(f, curr_elem, size, NULL, NULL);
+                } else if (field->flags & VMS_STRUCT) {
+                    vmstate_save_state(f, field->vmsd, curr_elem, vmdesc_loop);
                 } else {
-                    field->info->put(f, addr, size);
+                    field->info->put(f, curr_elem, size, field, vmdesc_loop);
                 }
 
                 written_bytes = qemu_ftell_fast(f) - old_offset;
@@ -382,25 +397,25 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
         len = qemu_peek_byte(f, 1);
         if (len < strlen(vmsd->name) + 1) {
             /* subsection name has be be "section_name/a" */
-            trace_vmstate_subsection_load_bad(vmsd->name, "(short)");
+            trace_vmstate_subsection_load_bad(vmsd->name, "(short)", "");
             return 0;
         }
         size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2);
         if (size != len) {
-            trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)");
+            trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", "");
             return 0;
         }
         memcpy(idstr, idstr_ret, size);
         idstr[size] = 0;
 
         if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) {
-            trace_vmstate_subsection_load_bad(vmsd->name, idstr);
-            /* it don't have a valid subsection name */
+            trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)");
+            /* it doesn't have a valid subsection name */
             return 0;
         }
         sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr);
         if (sub_vmsd == NULL) {
-            trace_vmstate_subsection_load_bad(vmsd->name, "(lookup)");
+            trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)");
             return -ENOENT;
         }
         qemu_file_skip(f, 1); /* subsection */
@@ -410,7 +425,7 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
 
         ret = vmstate_load_state(f, sub_vmsd, opaque, version_id);
         if (ret) {
-            trace_vmstate_subsection_load_bad(vmsd->name, "(child)");
+            trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)");
             return ret;
         }
     }
@@ -425,11 +440,13 @@ static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
     const VMStateDescription **sub = vmsd->subsections;
     bool subsection_found = false;
 
+    trace_vmstate_subsection_save_top(vmsd->name);
     while (sub && *sub && (*sub)->needed) {
         if ((*sub)->needed(opaque)) {
-            const VMStateDescription *vmsd = *sub;
+            const VMStateDescription *vmsdsub = *sub;
             uint8_t len;
 
+            trace_vmstate_subsection_save_loop(vmsd->name, vmsdsub->name);
             if (vmdesc) {
                 /* Only create subsection array when we have any */
                 if (!subsection_found) {
@@ -441,11 +458,11 @@ static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
             }
 
             qemu_put_byte(f, QEMU_VM_SUBSECTION);
-            len = strlen(vmsd->name);
+            len = strlen(vmsdsub->name);
             qemu_put_byte(f, len);
-            qemu_put_buffer(f, (uint8_t *)vmsd->name, len);
-            qemu_put_be32(f, vmsd->version_id);
-            vmstate_save_state(f, vmsd, opaque, vmdesc);
+            qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len);
+            qemu_put_be32(f, vmsdsub->version_id);
+            vmstate_save_state(f, vmsdsub, opaque, vmdesc);
 
             if (vmdesc) {
                 json_end_object(vmdesc);
@@ -461,17 +478,19 @@ static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
 
 /* bool */
 
-static int get_bool(QEMUFile *f, void *pv, size_t size)
+static int get_bool(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     bool *v = pv;
     *v = qemu_get_byte(f);
     return 0;
 }
 
-static void put_bool(QEMUFile *f, void *pv, size_t size)
+static int put_bool(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                    QJSON *vmdesc)
 {
     bool *v = pv;
     qemu_put_byte(f, *v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_bool = {
@@ -482,17 +501,19 @@ const VMStateInfo vmstate_info_bool = {
 
 /* 8 bit int */
 
-static int get_int8(QEMUFile *f, void *pv, size_t size)
+static int get_int8(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int8_t *v = pv;
     qemu_get_s8s(f, v);
     return 0;
 }
 
-static void put_int8(QEMUFile *f, void *pv, size_t size)
+static int put_int8(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     int8_t *v = pv;
     qemu_put_s8s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_int8 = {
@@ -503,17 +524,19 @@ const VMStateInfo vmstate_info_int8 = {
 
 /* 16 bit int */
 
-static int get_int16(QEMUFile *f, void *pv, size_t size)
+static int get_int16(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int16_t *v = pv;
     qemu_get_sbe16s(f, v);
     return 0;
 }
 
-static void put_int16(QEMUFile *f, void *pv, size_t size)
+static int put_int16(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     int16_t *v = pv;
     qemu_put_sbe16s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_int16 = {
@@ -524,17 +547,19 @@ const VMStateInfo vmstate_info_int16 = {
 
 /* 32 bit int */
 
-static int get_int32(QEMUFile *f, void *pv, size_t size)
+static int get_int32(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int32_t *v = pv;
     qemu_get_sbe32s(f, v);
     return 0;
 }
 
-static void put_int32(QEMUFile *f, void *pv, size_t size)
+static int put_int32(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     int32_t *v = pv;
     qemu_put_sbe32s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_int32 = {
@@ -546,7 +571,8 @@ const VMStateInfo vmstate_info_int32 = {
 /* 32 bit int. See that the received value is the same than the one
    in the field */
 
-static int get_int32_equal(QEMUFile *f, void *pv, size_t size)
+static int get_int32_equal(QEMUFile *f, void *pv, size_t size,
+                           VMStateField *field)
 {
     int32_t *v = pv;
     int32_t v2;
@@ -555,6 +581,7 @@ static int get_int32_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%" PRIx32 " != %" PRIx32, *v, v2);
     return -EINVAL;
 }
 
@@ -568,7 +595,7 @@ const VMStateInfo vmstate_info_int32_equal = {
  * and less than or equal to the one in the field.
  */
 
-static int get_int32_le(QEMUFile *f, void *pv, size_t size)
+static int get_int32_le(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int32_t *cur = pv;
     int32_t loaded;
@@ -578,6 +605,9 @@ static int get_int32_le(QEMUFile *f, void *pv, size_t size)
         *cur = loaded;
         return 0;
     }
+    error_report("Invalid value %" PRId32
+                 " expecting positive value <= %" PRId32,
+                 loaded, *cur);
     return -EINVAL;
 }
 
@@ -589,17 +619,19 @@ const VMStateInfo vmstate_info_int32_le = {
 
 /* 64 bit int */
 
-static int get_int64(QEMUFile *f, void *pv, size_t size)
+static int get_int64(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     int64_t *v = pv;
     qemu_get_sbe64s(f, v);
     return 0;
 }
 
-static void put_int64(QEMUFile *f, void *pv, size_t size)
+static int put_int64(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     int64_t *v = pv;
     qemu_put_sbe64s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_int64 = {
@@ -610,17 +642,19 @@ const VMStateInfo vmstate_info_int64 = {
 
 /* 8 bit unsigned int */
 
-static int get_uint8(QEMUFile *f, void *pv, size_t size)
+static int get_uint8(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint8_t *v = pv;
     qemu_get_8s(f, v);
     return 0;
 }
 
-static void put_uint8(QEMUFile *f, void *pv, size_t size)
+static int put_uint8(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                     QJSON *vmdesc)
 {
     uint8_t *v = pv;
     qemu_put_8s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_uint8 = {
@@ -631,17 +665,19 @@ const VMStateInfo vmstate_info_uint8 = {
 
 /* 16 bit unsigned int */
 
-static int get_uint16(QEMUFile *f, void *pv, size_t size)
+static int get_uint16(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint16_t *v = pv;
     qemu_get_be16s(f, v);
     return 0;
 }
 
-static void put_uint16(QEMUFile *f, void *pv, size_t size)
+static int put_uint16(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     uint16_t *v = pv;
     qemu_put_be16s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_uint16 = {
@@ -652,17 +688,19 @@ const VMStateInfo vmstate_info_uint16 = {
 
 /* 32 bit unsigned int */
 
-static int get_uint32(QEMUFile *f, void *pv, size_t size)
+static int get_uint32(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint32_t *v = pv;
     qemu_get_be32s(f, v);
     return 0;
 }
 
-static void put_uint32(QEMUFile *f, void *pv, size_t size)
+static int put_uint32(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     uint32_t *v = pv;
     qemu_put_be32s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_uint32 = {
@@ -674,7 +712,8 @@ const VMStateInfo vmstate_info_uint32 = {
 /* 32 bit uint. See that the received value is the same than the one
    in the field */
 
-static int get_uint32_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint32_equal(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field)
 {
     uint32_t *v = pv;
     uint32_t v2;
@@ -683,6 +722,7 @@ static int get_uint32_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%" PRIx32 " != %" PRIx32, *v, v2);
     return -EINVAL;
 }
 
@@ -694,17 +734,19 @@ const VMStateInfo vmstate_info_uint32_equal = {
 
 /* 64 bit unsigned int */
 
-static int get_uint64(QEMUFile *f, void *pv, size_t size)
+static int get_uint64(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     uint64_t *v = pv;
     qemu_get_be64s(f, v);
     return 0;
 }
 
-static void put_uint64(QEMUFile *f, void *pv, size_t size)
+static int put_uint64(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     uint64_t *v = pv;
     qemu_put_be64s(f, v);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_uint64 = {
@@ -713,10 +755,39 @@ const VMStateInfo vmstate_info_uint64 = {
     .put  = put_uint64,
 };
 
+static int get_nullptr(QEMUFile *f, void *pv, size_t size, VMStateField *field)
+
+{
+    if (qemu_get_byte(f) == VMS_NULLPTR_MARKER) {
+        return  0;
+    }
+    error_report("vmstate: get_nullptr expected VMS_NULLPTR_MARKER");
+    return -EINVAL;
+}
+
+static int put_nullptr(QEMUFile *f, void *pv, size_t size,
+                        VMStateField *field, QJSON *vmdesc)
+
+{
+    if (pv == NULL) {
+        qemu_put_byte(f, VMS_NULLPTR_MARKER);
+        return 0;
+    }
+    error_report("vmstate: put_nullptr must be called with pv == NULL");
+    return -EINVAL;
+}
+
+const VMStateInfo vmstate_info_nullptr = {
+    .name = "uint64",
+    .get  = get_nullptr,
+    .put  = put_nullptr,
+};
+
 /* 64 bit unsigned int. See that the received value is the same than the one
    in the field */
 
-static int get_uint64_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint64_equal(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field)
 {
     uint64_t *v = pv;
     uint64_t v2;
@@ -725,6 +796,7 @@ static int get_uint64_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%" PRIx64 " != %" PRIx64, *v, v2);
     return -EINVAL;
 }
 
@@ -737,7 +809,8 @@ const VMStateInfo vmstate_info_uint64_equal = {
 /* 8 bit int. See that the received value is the same than the one
    in the field */
 
-static int get_uint8_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint8_equal(QEMUFile *f, void *pv, size_t size,
+                           VMStateField *field)
 {
     uint8_t *v = pv;
     uint8_t v2;
@@ -746,6 +819,7 @@ static int get_uint8_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%x != %x", *v, v2);
     return -EINVAL;
 }
 
@@ -758,7 +832,8 @@ const VMStateInfo vmstate_info_uint8_equal = {
 /* 16 bit unsigned int int. See that the received value is the same than the one
    in the field */
 
-static int get_uint16_equal(QEMUFile *f, void *pv, size_t size)
+static int get_uint16_equal(QEMUFile *f, void *pv, size_t size,
+                            VMStateField *field)
 {
     uint16_t *v = pv;
     uint16_t v2;
@@ -767,6 +842,7 @@ static int get_uint16_equal(QEMUFile *f, void *pv, size_t size)
     if (*v == v2) {
         return 0;
     }
+    error_report("%x != %x", *v, v2);
     return -EINVAL;
 }
 
@@ -778,7 +854,8 @@ const VMStateInfo vmstate_info_uint16_equal = {
 
 /* floating point */
 
-static int get_float64(QEMUFile *f, void *pv, size_t size)
+static int get_float64(QEMUFile *f, void *pv, size_t size,
+                       VMStateField *field)
 {
     float64 *v = pv;
 
@@ -786,11 +863,13 @@ static int get_float64(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_float64(QEMUFile *f, void *pv, size_t size)
+static int put_float64(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                       QJSON *vmdesc)
 {
     uint64_t *v = pv;
 
     qemu_put_be64(f, float64_val(*v));
+    return 0;
 }
 
 const VMStateInfo vmstate_info_float64 = {
@@ -801,7 +880,8 @@ const VMStateInfo vmstate_info_float64 = {
 
 /* CPU_DoubleU type */
 
-static int get_cpudouble(QEMUFile *f, void *pv, size_t size)
+static int get_cpudouble(QEMUFile *f, void *pv, size_t size,
+                         VMStateField *field)
 {
     CPU_DoubleU *v = pv;
     qemu_get_be32s(f, &v->l.upper);
@@ -809,11 +889,13 @@ static int get_cpudouble(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_cpudouble(QEMUFile *f, void *pv, size_t size)
+static int put_cpudouble(QEMUFile *f, void *pv, size_t size,
+                         VMStateField *field, QJSON *vmdesc)
 {
     CPU_DoubleU *v = pv;
     qemu_put_be32s(f, &v->l.upper);
     qemu_put_be32s(f, &v->l.lower);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_cpudouble = {
@@ -824,17 +906,20 @@ const VMStateInfo vmstate_info_cpudouble = {
 
 /* uint8_t buffers */
 
-static int get_buffer(QEMUFile *f, void *pv, size_t size)
+static int get_buffer(QEMUFile *f, void *pv, size_t size,
+                      VMStateField *field)
 {
     uint8_t *v = pv;
     qemu_get_buffer(f, v, size);
     return 0;
 }
 
-static void put_buffer(QEMUFile *f, void *pv, size_t size)
+static int put_buffer(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     uint8_t *v = pv;
     qemu_put_buffer(f, v, size);
+    return 0;
 }
 
 const VMStateInfo vmstate_info_buffer = {
@@ -846,7 +931,8 @@ const VMStateInfo vmstate_info_buffer = {
 /* unused buffers: space that was used for some fields that are
    not useful anymore */
 
-static int get_unused_buffer(QEMUFile *f, void *pv, size_t size)
+static int get_unused_buffer(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field)
 {
     uint8_t buf[1024];
     int block_len;
@@ -859,7 +945,8 @@ static int get_unused_buffer(QEMUFile *f, void *pv, size_t size)
    return 0;
 }
 
-static void put_unused_buffer(QEMUFile *f, void *pv, size_t size)
+static int put_unused_buffer(QEMUFile *f, void *pv, size_t size,
+                             VMStateField *field, QJSON *vmdesc)
 {
     static const uint8_t buf[1024];
     int block_len;
@@ -869,6 +956,8 @@ static void put_unused_buffer(QEMUFile *f, void *pv, size_t size)
         size -= block_len;
         qemu_put_buffer(f, buf, block_len);
     }
+
+    return 0;
 }
 
 const VMStateInfo vmstate_info_unused_buffer = {
@@ -877,6 +966,46 @@ 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
@@ -884,7 +1013,7 @@ const VMStateInfo vmstate_info_unused_buffer = {
  */
 /* This is the number of 64 bit words sent over the wire */
 #define BITS_TO_U64S(nr) DIV_ROUND_UP(nr, 64)
-static int get_bitmap(QEMUFile *f, void *pv, size_t size)
+static int get_bitmap(QEMUFile *f, void *pv, size_t size, VMStateField *field)
 {
     unsigned long *bmp = pv;
     int i, idx = 0;
@@ -898,7 +1027,8 @@ static int get_bitmap(QEMUFile *f, void *pv, size_t size)
     return 0;
 }
 
-static void put_bitmap(QEMUFile *f, void *pv, size_t size)
+static int put_bitmap(QEMUFile *f, void *pv, size_t size, VMStateField *field,
+                      QJSON *vmdesc)
 {
     unsigned long *bmp = pv;
     int i, idx = 0;
@@ -909,6 +1039,8 @@ static void put_bitmap(QEMUFile *f, void *pv, size_t size)
         }
         qemu_put_be64(f, w);
     }
+
+    return 0;
 }
 
 const VMStateInfo vmstate_info_bitmap = {
@@ -916,3 +1048,71 @@ 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,
+};