If the outgoing machine was previously suspended, propagate that to the
incoming side via global_state, so a subsequent vm_start restores the
suspended state. To maintain backward and forward compatibility, reclaim
some space from the runstate member.
Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
migration/global_state.c | 35 +++++++++++++++++++++++++++++++++--
1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/migration/global_state.c b/migration/global_state.c
index 4e2a9d8..d4f61a1 100644
--- a/migration/global_state.c
+++ b/migration/global_state.c
@@ -22,7 +22,16 @@
typedef struct {
uint32_t size;
- uint8_t runstate[100];
+
+ /*
+ * runstate was 100 bytes, zero padded, but we trimmed it to add a
+ * few fields and maintain backwards compatibility.
+ */
+ uint8_t runstate[32];
+ uint8_t has_vm_was_suspended;
+ uint8_t vm_was_suspended;
+ uint8_t unused[66];
+
RunState state;
bool received;
} GlobalState;
@@ -35,6 +44,10 @@ static void global_state_do_store(RunState state)
assert(strlen(state_str) < sizeof(global_state.runstate));
strpadcpy((char *)global_state.runstate, sizeof(global_state.runstate),
state_str, '\0');
+ global_state.has_vm_was_suspended = true;
+ global_state.vm_was_suspended = vm_get_suspended();
+
+ memset(global_state.unused, 0, sizeof(global_state.unused));
}
void global_state_store(void)
@@ -68,6 +81,12 @@ static bool global_state_needed(void *opaque)
return true;
}
+ /* If the suspended state must be remembered, it is needed */
+
+ if (vm_get_suspended()) {
+ return true;
+ }
+
/* If state is running or paused, it is not needed */
if (strcmp(runstate, "running") == 0 ||
@@ -85,6 +104,7 @@ static int global_state_post_load(void *opaque, int
version_id)
Error *local_err = NULL;
int r;
char *runstate = (char *)s->runstate;
+ bool vm_was_suspended = s->has_vm_was_suspended && s->vm_was_suspended;
s->received = true;
trace_migrate_global_state_post_load(runstate);
@@ -93,7 +113,7 @@ static int global_state_post_load(void *opaque, int
version_id)
sizeof(s->runstate)) == sizeof(s->runstate)) {
/*
* This condition should never happen during migration, because
- * all runstate names are shorter than 100 bytes (the size of
+ * all runstate names are shorter than 32 bytes (the size of
* s->runstate). However, a malicious stream could overflow
* the qapi_enum_parse() call, so we force the last character
* to a NUL byte.
@@ -110,6 +130,14 @@ static int global_state_post_load(void *opaque, int
version_id)
}
s->state = r;
+ /*
+ * global_state is saved on the outgoing side before forcing a stopped
+ * state, so it may have saved state=suspended and vm_was_suspended=0.
+ * Now we are in a paused state, and when we later call vm_start, it must
+ * restore the suspended state, so we must set vm_was_suspended=1 here.
+ */
+ vm_set_suspended(vm_was_suspended || r == RUN_STATE_SUSPENDED);
+
return 0;
}
@@ -134,6 +162,9 @@ static const VMStateDescription vmstate_globalstate = {
.fields = (VMStateField[]) {
VMSTATE_UINT32(size, GlobalState),
VMSTATE_BUFFER(runstate, GlobalState),
+ VMSTATE_UINT8(has_vm_was_suspended, GlobalState),
+ VMSTATE_UINT8(vm_was_suspended, GlobalState),
+ VMSTATE_BUFFER(unused, GlobalState),
VMSTATE_END_OF_LIST()
},
};
--
1.8.3.1
