From: Steve Sistare <steven.sist...@oracle.com> 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> Reviewed-by: Peter Xu <pet...@redhat.com> Link: https://lore.kernel.org/r/1704312341-66640-6-git-send-email-steven.sist...@oracle.com Signed-off-by: Peter Xu <pet...@redhat.com> --- migration/global_state.c | 47 +++++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 20 deletions(-) diff --git a/migration/global_state.c b/migration/global_state.c index 4e2a9d8ec0..64a573c683 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) @@ -59,24 +72,7 @@ RunState global_state_get_runstate(void) static bool global_state_needed(void *opaque) { - GlobalState *s = opaque; - char *runstate = (char *)s->runstate; - - /* If it is not optional, it is mandatory */ - - if (migrate_get_current()->store_global_state) { - return true; - } - - /* If state is running or paused, it is not needed */ - - if (strcmp(runstate, "running") == 0 || - strcmp(runstate, "paused") == 0) { - return false; - } - - /* for any other state it is needed */ - return true; + return migrate_get_current()->store_global_state; } static int global_state_post_load(void *opaque, int version_id) @@ -93,7 +89,7 @@ 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 +106,14 @@ 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(s->vm_was_suspended || r == RUN_STATE_SUSPENDED); + return 0; } @@ -134,6 +138,9 @@ 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() }, }; -- 2.41.0
