From f32935ea2284fe833fdf4a0d6b2fe423fc08a1b2 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Fri, 30 May 2014 19:34:19 +1000 Subject: [PATCH] vmstate: Add preallocation for migrating arrays (VMS_ALLOC flag) 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. Signed-off-by: Alexey Kardashevskiy Reviewed-by: Juan Quintela [agraf: drop g_malloc_n usage] Signed-off-by: Alexander Graf --- 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 71a8a95641..9a001bd28f 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 c9965205df..ef2f87bdad 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) { + gsize size = n_elems * field->size; + *((void **)base_addr + field->start) = g_malloc(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); @@ -135,7 +142,7 @@ 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);