summaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorSascha Silbe <silbe@linux.vnet.ibm.com>2016-02-26 09:18:13 +0100
committerAmit Shah <amit.shah@redhat.com>2016-02-26 18:40:30 +0530
commit8da5ef579f956857ca1887ce0bc5e189dd9de0c4 (patch)
treee13340ec97fd899aa82116e8881b02a1affd331c /include
parenta609ad8b6924c0476e3c3d4b8e9079974d3c6ecf (diff)
downloadqemu-8da5ef579f956857ca1887ce0bc5e189dd9de0c4.tar.gz
migration/vmstate: document VMStateFlags
The VMState API is rather sparsely documented. Start by describing the meaning of all VMStateFlags. Reviewed-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com> Message-Id: <1456474693-11662-1-git-send-email-silbe@linux.vnet.ibm.com> Signed-off-by: Amit Shah <amit.shah@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/migration/vmstate.h100
1 files changed, 90 insertions, 10 deletions
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 7246f29afe..84ee355ceb 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -88,21 +88,101 @@ struct VMStateInfo {
};
enum VMStateFlags {
+ /* Ignored */
VMS_SINGLE = 0x001,
+
+ /* The struct member at opaque + VMStateField.offset is a pointer
+ * to the actual field (e.g. struct a { uint8_t *b;
+ * }). Dereference the pointer before using it as basis for
+ * further pointer arithmetic (see e.g. VMS_ARRAY). Does not
+ * affect the meaning of VMStateField.num_offset or
+ * VMStateField.size_offset; see VMS_VARRAY* and VMS_VBUFFER for
+ * those. */
VMS_POINTER = 0x002,
+
+ /* The field is an array of fixed size. VMStateField.num contains
+ * the number of entries in the array. The size of each entry is
+ * given by VMStateField.size and / or opaque +
+ * VMStateField.size_offset; see VMS_VBUFFER and
+ * VMS_MULTIPLY. Each array entry will be processed individually
+ * (VMStateField.info.get()/put() if VMS_STRUCT is not set,
+ * recursion into VMStateField.vmsd if VMS_STRUCT is set). May not
+ * be combined with VMS_VARRAY*. */
VMS_ARRAY = 0x004,
+
+ /* The field is itself a struct, containing one or more
+ * fields. Recurse into VMStateField.vmsd. Most useful in
+ * combination with VMS_ARRAY / VMS_VARRAY*, recursing into each
+ * array entry. */
VMS_STRUCT = 0x008,
- VMS_VARRAY_INT32 = 0x010, /* Array with size in int32_t field*/
- VMS_BUFFER = 0x020, /* static sized buffer */
+
+ /* The field is an array of variable size. The int32_t at opaque +
+ * VMStateField.num_offset contains the number of entries in the
+ * array. See the VMS_ARRAY description regarding array handling
+ * in general. May not be combined with VMS_ARRAY or any other
+ * VMS_VARRAY*. */
+ VMS_VARRAY_INT32 = 0x010,
+
+ /* Ignored */
+ VMS_BUFFER = 0x020,
+
+ /* The field is a (fixed-size or variable-size) array of pointers
+ * (e.g. struct a { uint8_t *b[]; }). Dereference each array entry
+ * before using it. Note: Does not imply any one of VMS_ARRAY /
+ * VMS_VARRAY*; these need to be set explicitly. */
VMS_ARRAY_OF_POINTER = 0x040,
- VMS_VARRAY_UINT16 = 0x080, /* Array with size in uint16_t field */
- VMS_VBUFFER = 0x100, /* Buffer with size in int32_t field */
- VMS_MULTIPLY = 0x200, /* multiply "size" field by field_size */
- VMS_VARRAY_UINT8 = 0x400, /* Array with size in uint8_t field*/
- VMS_VARRAY_UINT32 = 0x800, /* Array with size in uint32_t field*/
- VMS_MUST_EXIST = 0x1000, /* Field must exist in input */
- VMS_ALLOC = 0x2000, /* Alloc a buffer on the destination */
- VMS_MULTIPLY_ELEMENTS = 0x4000, /* multiply varray size by field->num */
+
+ /* The field is an array of variable size. The uint16_t at opaque
+ * + VMStateField.num_offset (subject to VMS_MULTIPLY_ELEMENTS)
+ * contains the number of entries in the array. See the VMS_ARRAY
+ * description regarding array handling in general. May not be
+ * combined with VMS_ARRAY or any other VMS_VARRAY*. */
+ VMS_VARRAY_UINT16 = 0x080,
+
+ /* The size of the individual entries (a single array entry if
+ * VMS_ARRAY or any of VMS_VARRAY* are set, or the field itself if
+ * neither is set) is variable (i.e. not known at compile-time),
+ * but the same for all entries. Use the int32_t at opaque +
+ * VMStateField.size_offset (subject to VMS_MULTIPLY) to determine
+ * the size of each (and every) entry. */
+ VMS_VBUFFER = 0x100,
+
+ /* Multiply the entry size given by the int32_t at opaque +
+ * VMStateField.size_offset (see VMS_VBUFFER description) with
+ * VMStateField.size to determine the number of bytes to be
+ * allocated. Only valid in combination with VMS_VBUFFER. */
+ VMS_MULTIPLY = 0x200,
+
+ /* The field is an array of variable size. The uint8_t at opaque +
+ * VMStateField.num_offset (subject to VMS_MULTIPLY_ELEMENTS)
+ * contains the number of entries in the array. See the VMS_ARRAY
+ * description regarding array handling in general. May not be
+ * combined with VMS_ARRAY or any other VMS_VARRAY*. */
+ VMS_VARRAY_UINT8 = 0x400,
+
+ /* The field is an array of variable size. The uint32_t at opaque
+ * + VMStateField.num_offset (subject to VMS_MULTIPLY_ELEMENTS)
+ * contains the number of entries in the array. See the VMS_ARRAY
+ * description regarding array handling in general. May not be
+ * combined with VMS_ARRAY or any other VMS_VARRAY*. */
+ VMS_VARRAY_UINT32 = 0x800,
+
+ /* Fail loading the serialised VM state if this field is missing
+ * from the input. */
+ VMS_MUST_EXIST = 0x1000,
+
+ /* When loading serialised VM state, allocate memory for the
+ * (entire) field. Only valid in combination with
+ * VMS_POINTER. Note: Not all combinations with other flags are
+ * currently supported, e.g. VMS_ALLOC|VMS_ARRAY_OF_POINTER won't
+ * cause the individual entries to be allocated. */
+ VMS_ALLOC = 0x2000,
+
+ /* Multiply the number of entries given by the integer at opaque +
+ * VMStateField.num_offset (see VMS_VARRAY*) with VMStateField.num
+ * to determine the number of entries in the array. Only valid in
+ * combination with one of VMS_VARRAY*. */
+ VMS_MULTIPLY_ELEMENTS = 0x4000,
};
typedef struct {