Re: [Qemu-devel] [qemu-s390x] [PATCH v1] hw/s390x: Allow to configure the consoles with the "-serial" parameter

[Peter Maydell]

On 25 April 2018 at 15:00, Thomas Huth  wrote:
> On 25.04.2018 14:31, Peter Maydell wrote:
>> Note that I have a series on-list which removes the MAX_SERIAL_PORTS
>> restriction, so you can have arbitrarily many serial ports.
>> (If that gets into master before this there'll be a conflict,
>> but it's easy to resolve: just change "serial_hds[n]" to "serial_hd(n)".)
>
> Ok, that should be pretty easy to resolve, indeed.

The MAX_SERIAL_PORTS series is now in master.

thanks
-- PMM

Re: [Qemu-devel] [qemu-s390x] [PATCH v1] hw/s390x: Allow to configure the consoles with the "-serial" parameter

[Thomas Huth]

On 25.04.2018 14:31, Peter Maydell wrote:
> On 25 April 2018 at 11:17, Thomas Huth  wrote:
>> On 25.04.2018 11:50, David Hildenbrand wrote:
>>> On 25.04.2018 07:21, 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, even for virtual
 consoles like spapr-vty on the pseries machine. So let's support this
 option on s390x, too. This way we can easily enable the serial console
 here again with "-nodefaults", for example:
> 
 +/* init consoles */
 +if (serial_hds[0]) {
 +s390_create_sclpconsole("sclpconsole", serial_hds[0]);
 +}
 +if (serial_hds[1]) {
 +s390_create_sclpconsole("sclplmconsole", serial_hds[1]);
 +}
>>>
>>> What happens if more -serial are defined? An error? Silently ignored?
>>
>> Silently ignored, since this is also what almost all other machines are
>> doing (look for serial_hds in hw/ and you'll see what I mean).
>>
>>> (e.g. do we have to redefine MAX_SERIAL_PORTS on s390x or add checking
>>> code here?)
>>
>> As all the other machines are also not redefining MAX_SERIAL_PORTS, I
>> think we should also not do this on s390x now, should we?
> 
> Note that I have a series on-list which removes the MAX_SERIAL_PORTS
> restriction, so you can have arbitrarily many serial ports.

Ah, great, good idea. Thanks for the hint, I was not aware of that patch
series yet.

> (If that gets into master before this there'll be a conflict,
> but it's easy to resolve: just change "serial_hds[n]" to "serial_hd(n)".)

Ok, that should be pretty easy to resolve, indeed.

 Thomas

Re: [Qemu-devel] [qemu-s390x] [PATCH v1] hw/s390x: Allow to configure the consoles with the "-serial" parameter

[Thomas Huth]

On 25.04.2018 07:21, 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, even for virtual
> consoles like spapr-vty on the pseries machine. So let's support this
> option on s390x, too. This way we can easily enable the serial console
> here again with "-nodefaults", for example:
> 
> qemu-system-s390x -no-shutdown -nographic -nodefaults -serial mon:stdio
> 
> ... which is way shorter than typing:
> 
> qemu-system-s390x -no-shutdown -nographic -nodefaults \
>   -chardev stdio,id=c1,mux=on -device sclpconsole,chardev=c1 \
>   -mon chardev=c1
> 
> The -serial parameter can also be used if you only want to see the QEMU
> monitor on stdio without using -nodefaults, but not the console output.
> That's something that is pretty impossible with the current code today:
> 
> qemu-system-s390x -no-shutdown -nographic -serial none
> 
> While we're at it, this patch also maps the second -serial option to the
> "sclplmconsole", so that there is now an easy way to configure this second
> console on s390x, too, for example:
> 
> qemu-system-s390x -no-shutdown -nographic -serial null -serial mon:stdio
> 
> Additionally, the new code is also smaller than the old one and we have
> less s390x-specific code in vl.c :-)
> 
> I've also checked that migration still works as expected by migrating
> a guest with console output back and forth between a qemu-system-s390x
> that has this patch and an instance without this patch.

... but I missed to run "make check" ... mea culpa. I need to update
tests/boot-serial-test.c now that we support -serial on s390x ... will
send a v2 with the fix.

 Thomas