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[Qemu-devel] [PULL 03/27] migration/vmstate: split up vmstate_base_addr
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PULL 03/27] migration/vmstate: split up vmstate_base_addr |
Date: |
Tue, 28 Feb 2017 12:40:32 +0000 |
From: Halil Pasic <address@hidden>
Currently vmstate_base_addr does several things: it pinpoints the field
within the struct, possibly allocates memory and possibly does the first
pointer dereference. Obviously allocation is needed only for load.
Let us split up the functionality in vmstate_base_addr and move the
address manipulations (that is everything but the allocation logic) to
load and save so it becomes more obvious what is actually going on. Like
this all the address calculations (and the handling of the flags
controlling these) is in one place and the sequence is more obvious.
The newly introduced function vmstate_handle_alloc also fixes the
allocation for the unused VMS_VBUFFER|VMS_MULTIPLY|VMS_ALLOC scenario
and is substantially simpler than the original vmstate_base_addr.
In load and save some asserts are added so it's easier to debug
situations where we would end up with a null pointer dereference.
Signed-off-by: Halil Pasic <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
migration/vmstate.c | 39 +++++++++++++++++----------------------
1 file changed, 17 insertions(+), 22 deletions(-)
diff --git a/migration/vmstate.c b/migration/vmstate.c
index 36efa80..836a7a4 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -52,29 +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 = 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;
}
-
- return base_addr;
}
int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
@@ -116,10 +102,15 @@ int vmstate_load_state(QEMUFile *f, const
VMStateDescription *vmsd,
field->field_exists(opaque, version_id)) ||
(!field->field_exists &&
field->version_id <= version_id)) {
- void *first_elem = 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);
+ }
for (i = 0; i < n_elems; i++) {
void *curr_elem = first_elem + size * i;
@@ -321,13 +312,17 @@ void vmstate_save_state(QEMUFile *f, const
VMStateDescription *vmsd,
while (field->name) {
if (!field->field_exists ||
field->field_exists(opaque, vmsd->version_id)) {
- void *first_elem = 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);
+ }
for (i = 0; i < n_elems; i++) {
void *curr_elem = first_elem + size * i;
--
2.9.3
- [Qemu-devel] [PULL 00/27] migration queue, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 01/27] Changing error message of QMP 'migrate_set_downtime' to seconds, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 02/27] migration/vmstate: renames in (load|save)_state, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 03/27] migration/vmstate: split up vmstate_base_addr,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PULL 04/27] migration/vmstate: fix array of ptr with nullptrs, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 05/27] tests/test-vmstate.c: test array of ptr with null, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 06/27] tests/test-vmstate.c: test array of ptr to primitive, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 07/27] vmstate-static-checker: update white list with spapr_pci, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 08/27] migrate: Introduce a 'dc->vmsd' check to avoid segfault for --only-migratable, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 09/27] migration: fix id leak regression, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 10/27] migration: Update docs to discourage version bumps, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 12/27] postcopy: Transmit ram size summary word, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 11/27] migration: fix use-after-free of to_dst_file, Dr. David Alan Gilbert (git), 2017/02/28
- [Qemu-devel] [PULL 13/27] postcopy: Transmit and compare individual page sizes, Dr. David Alan Gilbert (git), 2017/02/28