Re: [Qemu-devel] [PATCH v10 6/6] ppc: spapr: Handle "ibm, nmi-register" and "ibm, nmi-interlock" RTAS calls

[Aravinda Prasad]

On Monday 24 June 2019 07:59 PM, Greg Kurz wrote:
> On Wed, 12 Jun 2019 14:51:38 +0530
> Aravinda Prasad <address@hidden> wrote:
> 
>> This patch adds support in QEMU to handle "ibm,nmi-register"
>> and "ibm,nmi-interlock" RTAS calls and sets the default
>> value of SPAPR_CAP_FWNMI_MCE to SPAPR_CAP_ON for machine
>> type 4.0.
>>
> 
> Next machine type is 4.1.

ok.

> 
>> 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 that also received a machine check error waits
>> till the first processor is done reading the error log.
>> The first processor issues "ibm,nmi-interlock" call
>> when the error log is consumed.
>>
>> Signed-off-by: Aravinda Prasad <address@hidden>
>> ---
>>  hw/ppc/spapr.c         |    6 ++++-
>>  hw/ppc/spapr_rtas.c    |   63 
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>  include/hw/ppc/spapr.h |    5 +++-
>>  3 files changed, 72 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index 3d6d139..213d493 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -2946,6 +2946,9 @@ static void spapr_machine_init(MachineState *machine)
>>          /* Create the error string for live migration blocker */
>>          error_setg(&spapr->fwnmi_migration_blocker,
>>                  "Live migration not supported during machine check 
>> handling");
>> +
>> +        /* Register ibm,nmi-register and ibm,nmi-interlock RTAS calls */
>> +        spapr_fwnmi_register();
> 
> IIRC this was supposed to depend on SPAPR_CAP_FWNMI_MCE being ON.

Yes this is inside SPAPR_CAP_FWNMI_MCE check:

if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_ON) {
    /*
     * Ensure that the rtas image size is less than RTAS_ERROR_LOG_OFFSET
     * or else the rtas image will be overwritten with the rtas error log
     * when a machine check exception is encountered.
     */
    g_assert(spapr->rtas_size < RTAS_ERROR_LOG_OFFSET);

    /* Resize rtas blob to accommodate error log */
    spapr->rtas_size = RTAS_ERROR_LOG_MAX;

    /* Create the error string for live migration blocker */
    error_setg(&spapr->fwnmi_migration_blocker,
            "Live migration not supported during machine check handling");

    /* Register ibm,nmi-register and ibm,nmi-interlock RTAS calls */
    spapr_fwnmi_register();
}


> 
>>      }
>>  
>>      spapr->rtas_blob = g_malloc(spapr->rtas_size);
>> @@ -4408,7 +4411,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
>> void *data)
>>      smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
>>      smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_ON;
>>      smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF;
>> -    smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF;
>> +    smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_ON;
>>      spapr_caps_add_properties(smc, &error_abort);
>>      smc->irq = &spapr_irq_dual;
>>      smc->dr_phb_enabled = true;
>> @@ -4512,6 +4515,7 @@ static void 
>> spapr_machine_3_1_class_options(MachineClass *mc)
>>      smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_BROKEN;
>>      smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
>>      smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] = SPAPR_CAP_OFF;
>> +    smc->default_caps.caps[SPAPR_CAP_FWNMI_MCE] = SPAPR_CAP_OFF;
> 
> This should have been put into spapr_machine_4_0_class_options().

ok. I will change it.

> 
> But unless you manage to get this merged before soft-freeze (2019-07-02),
> I'm afraid this will be a 4.2 feature.

If there are no other comments, can this be merged to 4.1? I will send a
revised version with the above changes.

Regards,
Aravinda

> 
>>  }
>>  
>>  DEFINE_SPAPR_MACHINE(3_1, "3.1", false);
>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>> index a015a80..e010cb2 100644
>> --- a/hw/ppc/spapr_rtas.c
>> +++ b/hw/ppc/spapr_rtas.c
>> @@ -49,6 +49,7 @@
>>  #include "hw/ppc/fdt.h"
>>  #include "target/ppc/mmu-hash64.h"
>>  #include "target/ppc/mmu-book3s-v3.h"
>> +#include "migration/blocker.h"
>>  
>>  static void rtas_display_character(PowerPCCPU *cpu, SpaprMachineState 
>> *spapr,
>>                                     uint32_t token, uint32_t nargs,
>> @@ -352,6 +353,60 @@ 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)
>> +{
>> +    int ret;
>> +    hwaddr rtas_addr = spapr_get_rtas_addr();
>> +
>> +    if (!rtas_addr) {
>> +        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
>> +        return;
>> +    }
>> +
>> +    if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_OFF) {
>> +        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
>> +        return;
>> +    }
>> +
>> +    ret = kvmppc_fwnmi_enable(cpu);
>> +    if (ret == 1) {
>> +        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
>> +        return;
>> +    } else if (ret < 0) {
>> +        error_report("Couldn't enable KVM FWNMI capability");
>> +        rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
>> +        return;
>> +    }
>> +
>> +    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 == -1) {
>> +        /* 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_status.
>> +         */
>> +        spapr->mc_status = -1;
>> +        qemu_cond_signal(&spapr->mc_delivery_cond);
>> +        migrate_del_blocker(spapr->fwnmi_migration_blocker);
>> +        rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>> +    }
>> +}
>> +
>>  static struct rtas_call {
>>      const char *name;
>>      spapr_rtas_fn fn;
>> @@ -496,6 +551,14 @@ hwaddr spapr_get_rtas_addr(void)
>>      return (hwaddr)fdt32_to_cpu(*rtas_data);
>>  }
>>  
>> +void spapr_fwnmi_register(void)
>> +{
>> +    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);
>> +}
>> +
>>  static void core_rtas_register_types(void)
>>  {
>>      spapr_rtas_register(RTAS_DISPLAY_CHARACTER, "display-character",
>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>> index 0dedf0a..7ae53e2 100644
>> --- a/include/hw/ppc/spapr.h
>> +++ b/include/hw/ppc/spapr.h
>> @@ -637,8 +637,10 @@ 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
>> @@ -894,4 +896,5 @@ void spapr_check_pagesize(SpaprMachineState *spapr, 
>> hwaddr pagesize,
>>  
>>  void spapr_set_all_lpcrs(target_ulong value, target_ulong mask);
>>  hwaddr spapr_get_rtas_addr(void);
>> +void spapr_fwnmi_register(void);
>>  #endif /* HW_SPAPR_H */
>>
> 

-- 
Regards,
Aravinda