Re: [Qemu-ppc] [PATCH RFC 4/4] PPC: KVM: Expose possible VSMT modes via QMP and HMP

[David Gibson]

On Tue, Jun 27, 2017 at 10:23:02AM +1000, Sam Bobroff wrote:
> Use a new PPC KVM capability, KVM_PPC_CAP_SMT_POSSIBLE, to expose the
> valid VSMT modes to users via a new info subcommand ("info vsmt") and
> QMP clients.
> 
> Signed-off-by: Sam Bobroff <address@hidden>
> ---
>  accel/kvm/kvm-all.c       |  2 ++
>  hmp-commands-info.hx      | 14 ++++++++++++++
>  hmp.c                     | 16 ++++++++++++++++
>  hmp.h                     |  1 +
>  hw/ppc/spapr.c            |  1 +
>  include/sysemu/kvm.h      |  1 +
>  linux-headers/linux/kvm.h |  1 +
>  qapi-schema.json          | 28 ++++++++++++++++++++++++++++
>  qmp.c                     | 20 ++++++++++++++++++++
>  9 files changed, 84 insertions(+)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 75feffa504..fc44d3ae28 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -123,6 +123,7 @@ bool kvm_direct_msi_allowed;
>  bool kvm_ioeventfd_any_length_allowed;
>  bool kvm_msi_use_devid;
>  static bool kvm_immediate_exit;

A commit indicating that this is a bitmask of allowed modes might be
useful, to make it clear why this isn't a bool like most of the cap
values.

> +uint64_t kvmppc_smt_possible;
>  
>  static const KVMCapabilityInfo kvm_required_capabilites[] = {
>      KVM_CAP_INFO(USER_MEMORY),
> @@ -1721,6 +1722,7 @@ static int kvm_init(MachineState *ms)
>  #ifdef KVM_CAP_IRQ_ROUTING
>      kvm_direct_msi_allowed = (kvm_check_extension(s, KVM_CAP_SIGNAL_MSI) > 
> 0);
>  #endif
> +    kvmppc_smt_possible = kvm_check_extension(s, KVM_CAP_PPC_SMT_POSSIBLE);
>  
>      s->intx_set_mask = kvm_check_extension(s, KVM_CAP_PCI_2_3);
>  
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index ae169011b1..eb0ca52395 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -304,6 +304,20 @@ Show KVM information.
>  ETEXI
>  
>      {
> +        .name       = "vsmt",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "show VSMT information",
> +        .cmd        = hmp_info_vsmt,
> +    },
> +
> +STEXI
> address@hidden info vsmt
> address@hidden vsmt
> +Show VSMT information.
> +ETEXI
> +
> +    {
>          .name       = "numa",
>          .args_type  = "",
>          .params     = "",
> diff --git a/hmp.c b/hmp.c
> index 8c72c58b20..207668c112 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -95,6 +95,22 @@ void hmp_info_kvm(Monitor *mon, const QDict *qdict)
>      qapi_free_KvmInfo(info);
>  }
>  
> +void hmp_info_vsmt(Monitor *mon, const QDict *qdict)
> +{
> +    VsmtInfo *info;
> +    intList *entry;
> +
> +    info = qmp_query_vsmt(NULL);
> +    monitor_printf(mon, "Host KVM supports these VSMT modes:");
> +    entry = info->possible;
> +    while (entry) {
> +        monitor_printf(mon, " %ld", entry->value);
> +        entry = entry->next;
> +    }
> +    qapi_free_VsmtInfo(info);
> +    monitor_printf(mon, "\n");
> +}
> +

Hrm.  HMP and QMP commands just for looking at this seems like
overkill.

>  void hmp_info_status(Monitor *mon, const QDict *qdict)
>  {
>      StatusInfo *info;
> diff --git a/hmp.h b/hmp.h
> index d8b94ce9dc..dfda944231 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -22,6 +22,7 @@
>  void hmp_info_name(Monitor *mon, const QDict *qdict);
>  void hmp_info_version(Monitor *mon, const QDict *qdict);
>  void hmp_info_kvm(Monitor *mon, const QDict *qdict);
> +void hmp_info_vsmt(Monitor *mon, const QDict *qdict);
>  void hmp_info_status(Monitor *mon, const QDict *qdict);
>  void hmp_info_uuid(Monitor *mon, const QDict *qdict);
>  void hmp_info_chardev(Monitor *mon, const QDict *qdict);
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index c9ec1e87a1..d2536e2943 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2086,6 +2086,7 @@ static void ppc_set_vsmt_mode(sPAPRMachineState *spapr)
>      /* else TCG: nothing to do currently */
>      return;
>  error:
> +    error_report("Note: \"info vsmt\" shows supported VSMT modes (if any).");
>      exit(1);
>  
>  }
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 1e91613ca9..dcde6cdd2d 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -54,6 +54,7 @@ extern bool kvm_readonly_mem_allowed;
>  extern bool kvm_direct_msi_allowed;
>  extern bool kvm_ioeventfd_any_length_allowed;
>  extern bool kvm_msi_use_devid;
> +extern uint64_t kvmppc_smt_possible;
>  
>  #if defined CONFIG_KVM || !defined NEED_CPU_H
>  #define kvm_enabled()           (kvm_allowed)
> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> index d2892da172..be708cbf77 100644
> --- a/linux-headers/linux/kvm.h
> +++ b/linux-headers/linux/kvm.h
> @@ -895,6 +895,7 @@ struct kvm_ppc_resize_hpt {
>  #define KVM_CAP_SPAPR_TCE_VFIO 142
>  #define KVM_CAP_X86_GUEST_MWAIT 143
>  #define KVM_CAP_ARM_USER_IRQ 144
> +#define KVM_CAP_PPC_SMT_POSSIBLE 146 /* NEEDS HEADER UPDATE */
>  
>  #ifdef KVM_CAP_IRQ_ROUTING
>  
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 4b50b652d3..120721e658 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -230,6 +230,34 @@
>  { 'command': 'query-kvm', 'returns': 'KvmInfo' }
>  
>  ##
> +# @VsmtInfo:
> +#
> +# Information about VSMT modes
> +#
> +# @possible: list of available modes
> +#
> +# Since: 2.10
> +##
> +{ 'struct': 'VsmtInfo', 'data': {'possible': ['int'] } }
> +
> +##
> +# @query-vsmt:
> +#
> +# Returns information about VSMT modes
> +#
> +# Returns: @VsmtInfo
> +#
> +# Since: 2.10
> +#
> +# Example:
> +#
> +# -> { "execute": "query-vsmt" }
> +# <- { "return": { "possible": [8] } }
> +#
> +##
> +{ 'command': 'query-vsmt', 'returns': 'VsmtInfo' }
> +
> +##
>  # @RunState:
>  #
>  # An enumeration of VM run states.
> diff --git a/qmp.c b/qmp.c
> index 7ee9bcfdcf..7960e400e1 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -73,6 +73,26 @@ KvmInfo *qmp_query_kvm(Error **errp)
>      return info;
>  }
>  
> +VsmtInfo *qmp_query_vsmt(Error **errp)
> +{
> +    VsmtInfo *info = g_malloc0(sizeof(*info));
> +    intList *list = NULL, *entry;
> +    int i;
> +
> +    for (i = 63; i <= 0; i++) {
> +        if ((1 << i) & kvmppc_smt_possible) {
> +            entry = g_malloc0(sizeof(*entry));
> +            entry->value = (1UL << i);
> +            entry->next = list;
> +            list = entry;
> +        }
> +    }
> +
> +    info->possible = list;
> +
> +    return info;
> +}
> +
>  UuidInfo *qmp_query_uuid(Error **errp)
>  {
>      UuidInfo *info = g_malloc0(sizeof(*info));

-- 
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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