Re: [Qemu-devel] [PATCH 2/9] spapr: Compute effective capability values earlier

[Greg Kurz <groug@kaod.org>]

On Mon, 18 Jun 2018 16:35:59 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> Previously, the effective values of the various spapr capability flags
> were only determined at machine reset time.  That was a lazy way of making
> sure it was after cpu initialization so it could use the cpu object to
> inform the defaults.
> 
> But we've now improved the compat checking code so that we don't need to
> instantiate the cpus to use it.  That lets us move the resolution of the
> capability defaults much earlier.
> 
> This is going to be necessary for some future capabilities.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  hw/ppc/spapr.c         | 6 ++++--
>  hw/ppc/spapr_caps.c    | 9 ++++++---
>  include/hw/ppc/spapr.h | 3 ++-
>  3 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index b0b94fc1f0..40858d047c 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1612,7 +1612,7 @@ static void spapr_machine_reset(void)
>      void *fdt;
>      int rc;
>  
> -    spapr_caps_reset(spapr);
> +    spapr_caps_apply(spapr);
>  
>      first_ppc_cpu = POWERPC_CPU(first_cpu);
>      if (kvm_enabled() && kvmppc_has_cap_mmu_radix() &&
> @@ -2526,7 +2526,9 @@ static void spapr_machine_init(MachineState *machine)
>      QLIST_INIT(&spapr->phbs);
>      QTAILQ_INIT(&spapr->pending_dimm_unplugs);
>  
> -    /* Check HPT resizing availability */
> +    /* Determine capabilities to run with */
> +    spapr_caps_init(spapr);
> +
>      kvmppc_check_papr_resize_hpt(&resize_hpt_err);
>      if (spapr->resize_hpt == SPAPR_RESIZE_HPT_DEFAULT) {
>          /*
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index 469f38f0ef..dabed817d1 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -439,12 +439,12 @@ SPAPR_CAP_MIG_STATE(cfpc, SPAPR_CAP_CFPC);
>  SPAPR_CAP_MIG_STATE(sbbc, SPAPR_CAP_SBBC);
>  SPAPR_CAP_MIG_STATE(ibs, SPAPR_CAP_IBS);
>  
> -void spapr_caps_reset(sPAPRMachineState *spapr)
> +void spapr_caps_init(sPAPRMachineState *spapr)
>  {
>      sPAPRCapabilities default_caps;
>      int i;
>  
> -    /* First compute the actual set of caps we're running with.. */
> +    /* Compute the actual set of caps we should run with */
>      default_caps = default_caps_with_cpu(spapr, MACHINE(spapr)->cpu_type);
>  
>      for (i = 0; i < SPAPR_CAP_NUM; i++) {
> @@ -455,8 +455,11 @@ void spapr_caps_reset(sPAPRMachineState *spapr)
>              spapr->eff.caps[i] = default_caps.caps[i];
>          }
>      }
> +}
>  
> -    /* .. then apply those caps to the virtual hardware */
> +void spapr_caps_apply(sPAPRMachineState *spapr)
> +{
> +    int i;
>  
>      for (i = 0; i < SPAPR_CAP_NUM; i++) {
>          sPAPRCapabilityInfo *info = &capability_table[i];
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 3388750fc7..9dbd6010f5 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -798,7 +798,8 @@ static inline uint8_t spapr_get_cap(sPAPRMachineState *spapr, int cap)
>      return spapr->eff.caps[cap];
>  }
>  
> -void spapr_caps_reset(sPAPRMachineState *spapr);
> +void spapr_caps_init(sPAPRMachineState *spapr);
> +void spapr_caps_apply(sPAPRMachineState *spapr);
>  void spapr_caps_add_properties(sPAPRMachineClass *smc, Error **errp);
>  int spapr_caps_post_migration(sPAPRMachineState *spapr);
>