Re: [Qemu-devel] [PATCH v2] ppc: spapr-rtas - implement os-term rtas call

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

Alexander Graf <agraf@suse.de> writes:

> On 17.06.14 11:30, Nikunj A Dadhania wrote:
>> Alexander Graf <agraf@suse.de> writes:
>>
>>> On 12.06.14 14:09, Nikunj A Dadhania wrote:
>>>> PAPR compliant guest calls this in absence of kdump. After
>>>> receiving this call qemu could trigger a guest dump. This guest dump
>>>> can be used to analyse using crash tool.
>>>>
>>>> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
>>>> ---
>>>>
>>>> v2: indentation fixes
>>>>
>>>>    hw/ppc/spapr_rtas.c | 32 ++++++++++++++++++++++++++++++++
>>>>    1 file changed, 32 insertions(+)
>>>>
>>>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>>>> index ea4a2b2..f030e73 100644
>>>> --- a/hw/ppc/spapr_rtas.c
>>>> +++ b/hw/ppc/spapr_rtas.c
>>>> @@ -29,6 +29,8 @@
>>>>    #include "sysemu/char.h"
>>>>    #include "hw/qdev.h"
>>>>    #include "sysemu/device_tree.h"
>>>> +#include "qapi/qmp/qjson.h"
>>>> +#include "monitor/monitor.h"
>>>>    
>>>>    #include "hw/ppc/spapr.h"
>>>>    #include "hw/ppc/spapr_vio.h"
>>>> @@ -267,6 +269,34 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
>>>>        rtas_st(rets, 0, ret);
>>>>    }
>>>>    
>>>> +static void rtas_ibm_os_term(PowerPCCPU *cpu,
>>>> +                             sPAPREnvironment *spapr,
>>>> +                             uint32_t token, uint32_t nargs,
>>>> +                             target_ulong args,
>>>> +                             uint32_t nret, target_ulong rets)
>>>> +{
>>>> +    target_ulong ret = 0;
>>>> +    QObject *data;
>>>> +
>>>> +    data = qobject_from_jsonf("{ 'action': %s }", "pause");
>>>> +    monitor_protocol_event(QEVENT_GUEST_PANICKED, data);
>>>> +    qobject_decref(data);
>>>> +    vm_stop(RUN_STATE_GUEST_PANICKED);
>>>> +
>>>> +    rtas_st(rets, 0, ret);
>>>> +}
>>>> +
>>>> +static void rtas_ibm_ext_os_term(PowerPCCPU *cpu,
>>>> +                                 sPAPREnvironment *spapr,
>>>> +                                 uint32_t token, uint32_t nargs,
>>>> +                                 target_ulong args,
>>>> +                                 uint32_t nret, target_ulong rets)
>>>> +{
>>>> +    target_ulong ret = 0;
>>>> +
>>>> +    rtas_st(rets, 0, ret);
>>>> +}
>>>> +
>>>>    static struct rtas_call {
>>>>        const char *name;
>>>>        spapr_rtas_fn fn;
>>>> @@ -392,6 +422,8 @@ static void core_rtas_register_types(void)
>>>>                            rtas_ibm_get_system_parameter);
>>>>        spapr_rtas_register("ibm,set-system-parameter",
>>>>                            rtas_ibm_set_system_parameter);
>>>> +    spapr_rtas_register("ibm,os-term", rtas_ibm_os_term);
>>>> +    spapr_rtas_register("ibm,extended-os-term", rtas_ibm_ext_os_term);
>>> Why do we need the extended-os-term if we don't do anything with it?
>> Linux kernel checks for both of them because of legacy:
>>
>> arch/powerpc/kernel/rtas.c:
>>
>> void rtas_os_term(char *str)
>> {
>> [...]
>>          /*
>>           * Firmware with the ibm,extended-os-term property is guaranteed
>>           * to always return from an ibm,os-term call. Earlier versions without
>>           * this property may terminate the partition which we want to avoid
>>           * since it interferes with panic_timeout.
>
> But we do not return from the RTAS call, so we don't adhere to the 
> extended semantics?

But you would return without calling os-term call if
ibm,extended-os-term isnt registered. For that reason I h       ave defined a
stub.

Regards
Nikunj