Re: [Qemu-devel] [PATCH v2] s390x/cpu: expose the guest crash information

[Christian Borntraeger]

On 09/20/2017 11:14 AM, Cornelia Huck wrote:
> On Tue, 19 Sep 2017 09:43:14 +0200
> Christian Borntraeger <address@hidden> wrote:
> 
>> From: Jing Liu <address@hidden>
>>
>> This patch is the s390 implementation of guest crash information, similar
>> to commit d187e08dc4 ("i386/cpu: add crash-information QOM property") and
>> the related commits. We will detect several crash reasons, with the
>> "disabled wait" being the most important one, since this is used by all
>> s390 guests as a "panic like" notification.
>>
>> Demonstrate the these ways with examples as follows.
> 
> s/the these/these/
> 
>>
>>   1. crash-information QOM property;
>>
>>   Run qemu with -qmp unix:qmp-sock,server, then use utility "qmp-shell"
>>   to execute "qom-get" command, and might get the result like,
>>
>>   (QEMU) qom-get path=/machine/cpu[0]/ property=crash-information
>>   {"return": {"psw-addr": 1105350, "psw-mask": 562956395872256, "reason":
>>    "disabled wait", "type": "s390"}}
>>
>>   2. GUEST_PANICKED event reporting;
>>
>>   Run qemu with a socket option, and telnet or nc to that,
>>   -chardev socket,id=qmp,port=4444,host=localhost,server \
>>   -mon chardev=qmp,mode=control,pretty=on \
>>   Negotiating the mode by { "execute": "qmp_capabilities" }, and the crash
>>   information will be reported on a guest crash event like,
>>
>>   {
>>       "timestamp": {
>>           "seconds": 1499931739,
>>           "microseconds": 961296
>>       },
>>       "event": "GUEST_PANICKED",
>>       "data": {
>>           "action": "pause",
>>           "info": {
>>               "psw-addr": 1105350,
>>               "reason": "disabled wait",
>>               "psw-mask": 562956395872256,
>>               "type": "s390"
>>           }
>>       }
>>   }
> 
> Out of scope for this patch, but is there a way to print the values as
> hex in the monitor?

This is qmp, so I guess not?
> 
>>
>>   3. log;
>>
>>   Run qemu with the parameters: -D <logfile> -d guest_errors, to
>>   specify the logfile and log item. The results might be,
>>
>>   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>  
>>   Guest crashed
>>   S390 crash parameters: (0x2000180000000 0x10ddc6)
> 
> Would it make sense to pad with zeroes, for readability?

Yes, makes sense. 
> 
>>   S390 crash reason: disabled wait
>>   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>  
>>
>> Signed-off-by: Jing Liu <address@hidden>
>> Reviewed-by: Christian Borntraeger <address@hidden>
>> Signed-off-by: Christian Borntraeger <address@hidden>
>> [minor fixes due to upstream feedback]
>> ---
>> V1->V2:
>>      - rename kvm-s390 to s390 in all places
>>      - add "loop" to the crash reasons where appropriate
>>      - use "-" instead of "_" for qapi
>>
>>  qapi/run-state.json | 19 ++++++++++++++++--
>>  target/s390x/cpu.c  | 57 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  target/s390x/cpu.h  |  6 ++++++
>>  target/s390x/kvm.c  | 29 +++++++++++++++++++++------
>>  vl.c                |  6 ++++++
>>  5 files changed, 109 insertions(+), 8 deletions(-)
> 
> No further comments over what others have already said.
>