Re: [PATCH] hmp: Fix loadvm to resume the VM on success instead of failure

[Daniel P . Berrangé]

On Tue, May 11, 2021 at 06:31:51PM +0200, Kevin Wolf wrote:
> Commit f61fe11aa6f broke hmp_loadvm() by adding an incorrect negation
> when converting from 0/-errno return values to a bool value. The result
> is that loadvm resumes the VM now if it failed and keeps it stopped if
> it failed. Fix it to restore the old behaviour and do it the other way
> around.
> 
> Fixes: f61fe11aa6f7f8f0ffe4ddaa56a8108f3ab57854
> Cc: qemu-stable@nongnu.org
> Reported-by: Yanhui Ma <yama@redhat.com>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  monitor/hmp-cmds.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> index 0ad5b77477..cc15d9b6ee 100644
> --- a/monitor/hmp-cmds.c
> +++ b/monitor/hmp-cmds.c
> @@ -1133,7 +1133,7 @@ void hmp_loadvm(Monitor *mon, const QDict *qdict)
>  
>      vm_stop(RUN_STATE_RESTORE_VM);
>  
> -    if (!load_snapshot(name, NULL, false, NULL, &err) && saved_vm_running) {
> +    if (load_snapshot(name, NULL, false, NULL, &err) && saved_vm_running) {
>          vm_start();
>      }
>      hmp_handle_error(mon, err);

Paolo had sent a different fix here:

  https://lists.gnu.org/archive/html/qemu-devel/2021-05/msg01093.html

As with my feedback there, I think we should be adding test coverage
when fixing this. How about this:

diff --git a/tests/qemu-iotests/068 b/tests/qemu-iotests/068
index 54e49c8ffa..137c5d0577 100755
--- a/tests/qemu-iotests/068
+++ b/tests/qemu-iotests/068
@@ -77,7 +77,7 @@ for extra_args in \
     # Give qemu some time to boot before saving the VM state
     { sleep 1; printf "savevm 0\nquit\n"; } | _qemu $extra_args
     # Now try to continue from that VM state (this should just work)
-    { sleep 1; printf "loadvm 0\nloadvm 0\nquit\n"; } | _qemu $extra_args -S
+    { sleep 1; printf "info status\nloadvm 0\ninfo status\ncont\ninfo 
status\nloadvm 0\ninfo status\nquit\n"; } | _qemu $extra_args -S
 done
 
 # success, all done
diff --git a/tests/qemu-iotests/068.out b/tests/qemu-iotests/068.out
index f07a938a38..75c0a5df5f 100644
--- a/tests/qemu-iotests/068.out
+++ b/tests/qemu-iotests/068.out
@@ -7,8 +7,17 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm 0
 (qemu) quit
 QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) info status
+VM status: paused (prelaunch)
 (qemu) loadvm 0
+(qemu) info status
+VM status: paused (prelaunch)
+(qemu) cont
+(qemu) info status
+VM status: running
 (qemu) loadvm 0
+(qemu) info status
+VM status: running
 (qemu) quit
 
 === Saving and reloading a VM state to/from a qcow2 image (-object 
iothread,id=iothread0 -set device.hba0.iothread=iothread0) ===
@@ -18,7 +27,16 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm 0
 (qemu) quit
 QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) info status
+VM status: paused (prelaunch)
 (qemu) loadvm 0
+(qemu) info status
+VM status: paused (prelaunch)
+(qemu) cont
+(qemu) info status
+VM status: running
 (qemu) loadvm 0
+(qemu) info status
+VM status: running
 (qemu) quit
 *** done


Regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|