On 05/30/2014 07:34 PM, Alexey Kardashevskiy wrote:
> There are few helpers already to support array migration. However they all
> require the destination side to preallocate arrays before migration which
> is not always possible due to unknown array size as it might be some
> sort of dynamic state. One of the examples is an array of MSIX-enabled
> devices in SPAPR PHB - this array may vary from 0 to 65536 entries and
> its size depends on guest's ability to enable MSIX or do PCI hotplug.
>
> This adds new VMSTATE_VARRAY_STRUCT_ALLOC macro which is pretty similar to
> VMSTATE_STRUCT_VARRAY_POINTER_INT32 but it can alloc memory for migratign
> array on the destination side.
>
> This defines VMS_ALLOC flag for a field.
>
> This changes vmstate_base_addr() to do the allocation when receiving
> migration.
Juan, Peter? No hurry, just pinging in order not to forget :) Thanks!
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
> include/migration/vmstate.h | 11 +++++++++++
> vmstate.c | 13 ++++++++++---
> 2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index 7e45048..e794694 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -101,6 +101,7 @@ enum VMStateFlags {
> 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 */
> };
>
> typedef struct {
> @@ -429,6 +430,16 @@ extern const VMStateInfo vmstate_info_bitmap;
> .offset = offsetof(_state, _field), \
> }
>
> +#define VMSTATE_STRUCT_VARRAY_ALLOC(_field, _state, _field_num, _version,
> _vmsd, _type) {\
> + .name = (stringify(_field)), \
> + .version_id = (_version), \
> + .vmsd = &(_vmsd), \
> + .num_offset = vmstate_offset_value(_state, _field_num, int32_t), \
> + .size = sizeof(_type), \
> + .flags = VMS_STRUCT|VMS_VARRAY_INT32|VMS_ALLOC|VMS_POINTER, \
> + .offset = vmstate_offset_pointer(_state, _field, _type), \
> +}
> +
> #define VMSTATE_STATIC_BUFFER(_field, _state, _version, _test, _start,
> _size) { \
> .name = (stringify(_field)), \
> .version_id = (_version), \
> diff --git a/vmstate.c b/vmstate.c
> index b5882fa..fb95e39 100644
> --- a/vmstate.c
> +++ b/vmstate.c
> @@ -43,11 +43,18 @@ static int vmstate_size(void *opaque, VMStateField *field)
> return size;
> }
>
> -static void *vmstate_base_addr(void *opaque, VMStateField *field)
> +static void *vmstate_base_addr(void *opaque, VMStateField *field, bool alloc)
> {
> void *base_addr = opaque + field->offset;
>
> if (field->flags & VMS_POINTER) {
> + if (alloc && (field->flags & VMS_ALLOC)) {
> + int n_elems = vmstate_n_elems(opaque, field);
> + if (n_elems) {
> + *((void **)base_addr + field->start) = g_malloc_n(n_elems,
> +
> field->size);
> + }
> + }
> base_addr = *(void **)base_addr + field->start;
> }
>
> @@ -81,7 +88,7 @@ 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);
> + void *base_addr = vmstate_base_addr(opaque, field, true);
> int i, n_elems = vmstate_n_elems(opaque, field);
> int size = vmstate_size(opaque, field);
>
> @@ -131,7 +138,7 @@ 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);
> + void *base_addr = vmstate_base_addr(opaque, field, false);
> int i, n_elems = vmstate_n_elems(opaque, field);
> int size = vmstate_size(opaque, field);
>
>
--
Alexey
