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

[David Gibson <david@gibson.dropbear.id.au>]

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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"

> 
> > 
> > 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
> >>
> > 
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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