Re: [Qemu-devel] [PATCH v3 2/5] ppc: spapr: Handle "ibm, nmi-register" and "ibm, nmi-interlock" RTAS calls

[Aravinda Prasad <aravinda@linux.vnet.ibm.com>]

On Tuesday 22 August 2017 07:38 AM, David Gibson wrote:
> On Mon, Aug 21, 2017 at 06:05:34PM +0530, Aravinda Prasad wrote:
>>
>>
>> On Thursday 17 August 2017 07:09 AM, David Gibson wrote:
>>> What's with the extra spaces in the subject line?
>>
>> I don't see any. Can you pls point out?
> 
> I see "ibm, nmi-register" and "ibm, nmi-interlock"

Ah.. space after comma. Will correct it.

Regards,
Aravinda

> 
>>
>>>
>>> On Wed, Aug 16, 2017 at 02:42:21PM +0530, Aravinda Prasad wrote:
>>>> This patch adds support in QEMU to handle "ibm,nmi-register"
>>>> and "ibm,nmi-interlock" RTAS calls.
>>>>
>>>> The machine check notification address is saved when the
>>>> OS issues "ibm,nmi-register" RTAS call.
>>>>
>>>> This patch also handles the case when multiple processors
>>>> experience machine check at or about the same time by
>>>> handling "ibm,nmi-interlock" call. In such cases, as per
>>>> PAPR, subsequent processors serialize waiting for the first
>>>> processor to issue the "ibm,nmi-interlock" call. The second
>>>> processor waits till the first processor, which also
>>>> received a machine check error, is done reading the error
>>>> log. The first processor issues "ibm,nmi-interlock" call
>>>> when the error log is consumed. This patch implements the
>>>> releasing part of the error-log while subsequent patch
>>>> (which builds error log) handles the locking part.
>>>>
>>>> Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
>>>> ---
>>>>  hw/ppc/spapr.c         |    8 ++++++++
>>>>  hw/ppc/spapr_rtas.c    |   35 +++++++++++++++++++++++++++++++++++
>>>>  include/hw/ppc/spapr.h |   10 +++++++++-
>>>>  3 files changed, 52 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>>> index 2a3e53d..0bb2c4a 100644
>>>> --- a/hw/ppc/spapr.c
>>>> +++ b/hw/ppc/spapr.c
>>>> @@ -1441,6 +1441,11 @@ static void ppc_spapr_reset(void)
>>>>      first_ppc_cpu->env.nip = SPAPR_ENTRY_POINT;
>>>>  
>>>>      spapr->cas_reboot = false;
>>>> +
>>>> +    spapr->mc_in_progress = false;
>>>> +    spapr->guest_machine_check_addr = 0;
>>>> +    qemu_cond_destroy(&spapr->mc_delivery_cond);
>>>> +    qemu_cond_init(&spapr->mc_delivery_cond);
>>>>  }
>>>>  
>>>>  static void spapr_create_nvram(sPAPRMachineState *spapr)
>>>> @@ -2491,6 +2496,9 @@ static void ppc_spapr_init(MachineState *machine)
>>>>  
>>>>          kvmppc_spapr_enable_inkernel_multitce();
>>>>      }
>>>> +
>>>> +    spapr->mc_in_progress = false;
>>>> +    qemu_cond_init(&spapr->mc_delivery_cond);
>>>>  }
>>>>  
>>>>  static int spapr_kvm_type(const char *vm_type)
>>>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>>>> index 94a2799..2f3c47b 100644
>>>> --- a/hw/ppc/spapr_rtas.c
>>>> +++ b/hw/ppc/spapr_rtas.c
>>>> @@ -348,6 +348,37 @@ static void rtas_get_power_level(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>>>>      rtas_st(rets, 1, 100);
>>>>  }
>>>>  
>>>> +static void rtas_ibm_nmi_register(PowerPCCPU *cpu,
>>>> +                                  sPAPRMachineState *spapr,
>>>> +                                  uint32_t token, uint32_t nargs,
>>>> +                                  target_ulong args,
>>>> +                                  uint32_t nret, target_ulong rets)
>>>> +{
>>>> +    spapr->guest_machine_check_addr = rtas_ld(args, 1);
>>>> +    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>>>> +}
>>>> +
>>>> +static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
>>>> +                                   sPAPRMachineState *spapr,
>>>> +                                   uint32_t token, uint32_t nargs,
>>>> +                                   target_ulong args,
>>>> +                                   uint32_t nret, target_ulong rets)
>>>> +{
>>>> +    if (!spapr->guest_machine_check_addr) {
>>>> +        /* NMI register not called */
>>>> +        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
>>>> +    } else {
>>>> +        /*
>>>> +         * VCPU issuing "ibm,nmi-interlock" is done with NMI handling,
>>>> +         * hence unset mc_in_progress.
>>>> +         */
>>>> +        spapr->mc_in_progress = false;
>>>> +        qemu_cond_signal(&spapr->mc_delivery_cond);
>>>> +        rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>>>> +    }
>>>> +}
>>>> +
>>>> +
>>>>  static struct rtas_call {
>>>>      const char *name;
>>>>      spapr_rtas_fn fn;
>>>> @@ -489,6 +520,10 @@ static void core_rtas_register_types(void)
>>>>                          rtas_set_power_level);
>>>>      spapr_rtas_register(RTAS_GET_POWER_LEVEL, "get-power-level",
>>>>                          rtas_get_power_level);
>>>> +    spapr_rtas_register(RTAS_IBM_NMI_REGISTER, "ibm,nmi-register",
>>>> +                        rtas_ibm_nmi_register);
>>>> +    spapr_rtas_register(RTAS_IBM_NMI_INTERLOCK, "ibm,nmi-interlock",
>>>> +                        rtas_ibm_nmi_interlock);
>>>>  }
>>>>  
>>>>  type_init(core_rtas_register_types)
>>>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>>>> index 46012b3..eee8d33 100644
>>>> --- a/include/hw/ppc/spapr.h
>>>> +++ b/include/hw/ppc/spapr.h
>>>> @@ -123,6 +123,12 @@ struct sPAPRMachineState {
>>>>       * occurs during the unplug process. */
>>>>      QTAILQ_HEAD(, sPAPRDIMMState) pending_dimm_unplugs;
>>>>  
>>>> +    /* State related to "ibm,nmi-register" and "ibm,nmi-interlock" calls */
>>>> +    target_ulong guest_machine_check_addr;
>>>> +    bool mc_in_progress;
>>>> +    int mc_cpu;
>>>
>>> mc_cpu isn't actually used yet in this patch.  In any case it and
>>> mc_in_progress could probably be folded together, no?
>>
>> It is possible to fold mc_cpu and mc_in_progress together with the
>> convention that if it is set to -1 mc is not in progress otherwise it is
>> set to the CPU handling the mc.
>>
>>>
>>> These values will also need to be migrated, AFAICT.
>>
>> I am thinking of how to handle the migration when machine check handling
>> is in progress. Probably wait for machine check handling to complete
>> before migrating as the error could be irrelevant once migrated to a new
>> hardware. If that is the case we don't need to migrate these values.
> 
> Ok.
> 
>>
>> Regards,
>> Aravinda
>>
>>>
>>>> +    QemuCond mc_delivery_cond;
>>>> +
>>>>      /*< public >*/
>>>>      char *kvm_type;
>>>>      MemoryHotplugState hotplug_memory;
>>>> @@ -519,8 +525,10 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong opcode,
>>>>  #define RTAS_IBM_CREATE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x27)
>>>>  #define RTAS_IBM_REMOVE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x28)
>>>>  #define RTAS_IBM_RESET_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x29)
>>>> +#define RTAS_IBM_NMI_REGISTER                   (RTAS_TOKEN_BASE + 0x2A)
>>>> +#define RTAS_IBM_NMI_INTERLOCK                  (RTAS_TOKEN_BASE + 0x2B)
>>>>  
>>>> -#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2A)
>>>> +#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2C)
>>>>  
>>>>  /* RTAS ibm,get-system-parameter token values */
>>>>  #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20
>>>>
>>>
>>
> 

-- 
Regards,
Aravinda