Re: [qemu-s390x] [RFC PATCH] hw/s390x: Allow to configure the consoles with the "-serial" parameter

[Thomas Huth]

On 24.04.2018 16:09, Cornelia Huck wrote:
> On Tue, 24 Apr 2018 16:02:59 +0200
> Thomas Huth <address@hidden> wrote:
> 
>> On 24.04.2018 13:49, Christian Borntraeger wrote:
>>>
>>>
>>> On 04/24/2018 01:44 PM, Thomas Huth wrote:  
>>>> The consoles ("sclpconsole" and "sclplmconsole") can only be configured
>>>> with "-device" and "-chardev" so far. Other machines use the convenience
>>>> option "-serial" to configure the default consoles, too, even for virtual
>>>> consoles like spapr-vty on the pseries machine. So let's support this
>>>> option on s390x, too, so we can easily enable the serial console here
>>>> again with "-nodefaults", for example. Also map the second -serial
>>>> option to the "sclplmconsole", so that there is now an easy way to
>>>> configure this second console on s390x, too.
>>>> Additionally, the new code is also smaller than the old one and we have
>>>> less s390x-specific code in vl.c :-)  
[...]
>>> I read that as "the current command lines continue to work". Correct?  
>>
>> Right. I was a little bit afraid that this might break migration, but I
>> gave it a quick check and it still seems to work fine here.
>> "info qom-tree" and "info qtree" at the HMP monitor show slightly
>> different output, though ... not sure whether that's critical or not?
> 
> What looks different? If we still send/expect the same kind of
> information, it should not have any impact, I guess.

$ diff -u sclp-qtree-before.txt sclp-qtree-after.txt
--- sclp-qtree-before.txt       2018-04-24 16:17:14.527921927 +0200
+++ sclp-qtree-after.txt        2018-04-24 16:17:35.582877042 +0200
@@ -62,6 +62,6 @@
     bus: s390-sclp-events-bus.0
       type s390-sclp-events-bus
       dev: sclpconsole, id ""
-        chardev = "sclpcon0"
+        chardev = "serial0"
       dev: sclp-cpu-hotplug, id ""
       dev: sclpquiesce, id ""

... i.e. just the label of the chardev changed. I think that's ok, and
migration likely does not care about that.

$ diff -u sclp-qom-tree-before.txt sclp-qom-tree-after.txt
--- sclp-qom-tree-before.txt    2018-04-24 16:17:48.462849585 +0200
+++ sclp-qom-tree-after.txt     2018-04-24 16:18:02.222820256 +0200
@@ -1,13 +1,14 @@
-(qemu) info qom-tree
+(qemu) info qom-tree
 /machine (s390-ccw-virtio-2.12-machine)
   /unattached (container)
-    /system[0] (qemu:memory-region)
     /sysbus (System)
-    /device[1] (virtio-net-ccw)
+    /device[0] (qemu-s390x-cpu)
+    /s390.ram[0] (qemu:memory-region)
+    /device[1] (sclpconsole)
+    /device[2] (virtio-net-ccw)
       /virtio-backend (virtio-net-device)
       /virtio-bus (virtio-ccw-bus)
-    /s390.ram[0] (qemu:memory-region)
-    /device[0] (qemu-s390x-cpu)
+    /system[0] (qemu:memory-region)
     /io[0] (qemu:memory-region)
   /sclp (sclp)
     /s390-sclp-event-facility (s390-sclp-event-facility)
@@ -17,7 +18,6 @@
   /s390-flic-qemu (s390-flic-qemu)
   /s390-skeys (s390-skeys-qemu)
   /peripheral-anon (container)
-    /device[0] (sclpconsole)
   /peripheral (container)
   /s390-ipl (s390-ipl)
   /virtual-css-bridge (virtual-css-bridge)

... the sclpconsole now shows up under /unattached instead of
/peripheral-anon ... does that matter? (I don't have a clue)

 Thomas