Re: [Qemu-devel] [PATCH v2 5/5] s390x/cpumodel: Set up CPU model for AP device support

[Cornelia Huck <cohuck@redhat.com>]

On Tue, 27 Feb 2018 10:44:19 -0500
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:
> A new CPU model feature and two new CPU model facilities are
> introduced to support AP devices for a KVM guest.
> 
> CPU model features:
> 
> 1. The KVM_S390_VM_CPU_FEAT_AP CPU model feature indicates that
>    AP facilities are installed. This feature will be enabled by
>    the kernel only if the AP facilities are installed on the linux
>    host. This feature must be turned on from userspace to access
>    AP devices from the KVM guest. The QEMU command line to turn
>    this feature looks something like this:
> 
> 	qemu-system-s390x ... -cpu xxx,ap=on
> 
> CPU model facilities:
> 
> 1. The S390_FEAT_AP_QUERY_CONFIG_INFO feature indicates the AP Query
>    Configuration Information (QCI) facility is installed. This feature
>    will be enabled by the kernel only if the QCI is installed on
>    the host. This facility will be set by QEMU only if the
>    KVM_S390_VM_CPU_FEAT_AP CPU model feature is turned on.
>    (see CPU model features above)
> 
> 2. The S390_FEAT_AP_FACILITY_TEST feature indicates that the AP
>    Test Facility (APFT) facility is installed. This feature will
>    be enabled by the kernel only if the APFT facility is installed
>    on the host. This facility will be set by QEMU for the KVM guest
>    only if the KVM_S390_VM_CPU_FEAT_AP CPU model feature is turned on.
>    (see CPU model features above)
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
> ---
>  hw/vfio/ap.c                    |    9 +++++++++
>  linux-headers/asm-s390/kvm.h    |    1 +
>  target/s390x/cpu_features.c     |    3 +++
>  target/s390x/cpu_features_def.h |    3 +++
>  target/s390x/cpu_models.c       |   12 ++++++++++++
>  target/s390x/gen-features.c     |    3 +++
>  target/s390x/kvm.c              |    6 ++++++
>  7 files changed, 37 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
> index 8aa5221..b93f7d9 100644
> --- a/hw/vfio/ap.c
> +++ b/hw/vfio/ap.c
> @@ -19,6 +19,7 @@
>  #include "hw/s390x/ap-device.h"
>  #include "qemu/error-report.h"
>  #include "qemu/queue.h"
> +#include "cpu.h"
>  
>  #define VFIO_AP_DEVICE_TYPE      "vfio-ap"
>  #define AP_SYSFSDEV_PROP_NAME    "sysfsdev"
> @@ -87,6 +88,14 @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
>      Error *local_err = NULL;
>      int ret;
>  
> +    if (!s390_has_feat(S390_FEAT_AP)) {
> +        error_setg(&local_err, "Invalid device configuration: ");

"AP support not available" ?

[The hint is not visible in every circumstance IIRC]

> +        error_append_hint(&local_err,
> +                          "Verify AP facilities are enabled for the guest"
> +                          "(ap=on)\n");
> +        goto out_err;
> +    }
> +
>      vfio_group = vfio_ap_get_group(vapdev, &local_err);
>      if (!vfio_group) {
>          goto out_err;
> diff --git a/linux-headers/asm-s390/kvm.h b/linux-headers/asm-s390/kvm.h
> index 11def14..35a6d04 100644
> --- a/linux-headers/asm-s390/kvm.h
> +++ b/linux-headers/asm-s390/kvm.h
> @@ -130,6 +130,7 @@ struct kvm_s390_vm_cpu_machine {
>  #define KVM_S390_VM_CPU_FEAT_PFMFI	11
>  #define KVM_S390_VM_CPU_FEAT_SIGPIF	12
>  #define KVM_S390_VM_CPU_FEAT_KSS	13
> +#define KVM_S390_VM_CPU_FEAT_AP		14
>  struct kvm_s390_vm_cpu_feat {
>  	__u64 feat[16];
>  };

Shouldn't that hunk have been in the previous headers update already?

> diff --git a/target/s390x/cpu_features.c b/target/s390x/cpu_features.c
> index a5619f2..65b91bd 100644
> --- a/target/s390x/cpu_features.c
> +++ b/target/s390x/cpu_features.c
> @@ -36,8 +36,10 @@ static const S390FeatDef s390_features[] = {
>      FEAT_INIT("srs", S390_FEAT_TYPE_STFL, 9, "Sense-running-status facility"),
>      FEAT_INIT("csske", S390_FEAT_TYPE_STFL, 10, "Conditional-SSKE facility"),
>      FEAT_INIT("ctop", S390_FEAT_TYPE_STFL, 11, "Configuration-topology facility"),
> +    FEAT_INIT("qci", S390_FEAT_TYPE_STFL, 12, "Query AP Configuration facility"),
>      FEAT_INIT("ipter", S390_FEAT_TYPE_STFL, 13, "IPTE-range facility"),
>      FEAT_INIT("nonqks", S390_FEAT_TYPE_STFL, 14, "Nonquiescing key-setting facility"),
> +    FEAT_INIT("apft", S390_FEAT_TYPE_STFL, 15, "Adjunct Processor Facilities Test facility"),
>      FEAT_INIT("etf2", S390_FEAT_TYPE_STFL, 16, "Extended-translation facility 2"),
>      FEAT_INIT("msa-base", S390_FEAT_TYPE_STFL, 17, "Message-security-assist facility (excluding subfunctions)"),
>      FEAT_INIT("ldisp", S390_FEAT_TYPE_STFL, 18, "Long-displacement facility"),
> @@ -125,6 +127,7 @@ static const S390FeatDef s390_features[] = {
>  
>      FEAT_INIT("dateh2", S390_FEAT_TYPE_MISC, 0, "DAT-enhancement facility 2"),
>      FEAT_INIT("cmm", S390_FEAT_TYPE_MISC, 0, "Collaborative-memory-management facility"),
> +    FEAT_INIT("ap", S390_FEAT_TYPE_MISC, 1, "AP facilities installed"),

FEAT_TYPE_MISC does not use bit numbering (and there's a new
initializer for these bits queued in s390-next).

>  
>      FEAT_INIT("plo-cl", S390_FEAT_TYPE_PLO, 0, "PLO Compare and load (32 bit in general registers)"),
>      FEAT_INIT("plo-clg", S390_FEAT_TYPE_PLO, 1, "PLO Compare and load (64 bit in parameter list)"),
> diff --git a/target/s390x/cpu_features_def.h b/target/s390x/cpu_features_def.h
> index 7c5915c..8998b65 100644
> --- a/target/s390x/cpu_features_def.h
> +++ b/target/s390x/cpu_features_def.h
> @@ -27,8 +27,10 @@ typedef enum {
>      S390_FEAT_SENSE_RUNNING_STATUS,
>      S390_FEAT_CONDITIONAL_SSKE,
>      S390_FEAT_CONFIGURATION_TOPOLOGY,
> +    S390_FEAT_AP_QUERY_CONFIG_INFO,
>      S390_FEAT_IPTE_RANGE,
>      S390_FEAT_NONQ_KEY_SETTING,
> +    S390_FEAT_AP_FACILITIES_TEST,
>      S390_FEAT_EXTENDED_TRANSLATION_2,
>      S390_FEAT_MSA,
>      S390_FEAT_LONG_DISPLACEMENT,
> @@ -118,6 +120,7 @@ typedef enum {
>      /* Misc */
>      S390_FEAT_DAT_ENH_2,
>      S390_FEAT_CMM,
> +    S390_FEAT_AP,
>  
>      /* PLO */
>      S390_FEAT_PLO_CL,
> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
> index 1d5f0da..35f91ea 100644
> --- a/target/s390x/cpu_models.c
> +++ b/target/s390x/cpu_models.c
> @@ -770,6 +770,8 @@ static void check_consistency(const S390CPUModel *model)
>          { S390_FEAT_PRNO_TRNG_QRTCR, S390_FEAT_MSA_EXT_5 },
>          { S390_FEAT_PRNO_TRNG, S390_FEAT_MSA_EXT_5 },
>          { S390_FEAT_SIE_KSS, S390_FEAT_SIE_F2 },
> +        { S390_FEAT_AP_QUERY_CONFIG_INFO, S390_FEAT_AP },
> +        { S390_FEAT_AP_FACILITIES_TEST, S390_FEAT_AP },
>      };
>      int i;
>  
> @@ -900,6 +902,16 @@ void s390_realize_cpu_model(CPUState *cs, Error **errp)
>      cpu->model->cpu_id_format = max_model->cpu_id_format;
>      cpu->model->cpu_ver = max_model->cpu_ver;
>  
> +    /*
> +     * If the AP facilities are not installed on the guest, then it makes


"not provided in the model" ?

> +     * no sense to enable the QCI or APFT facilities because they are only
> +     * needed by AP facilities.
> +     */
> +    if (!test_bit(S390_FEAT_AP, cpu->model->features)) {
> +        clear_bit(S390_FEAT_AP_QUERY_CONFIG_INFO, cpu->model->features);
> +        clear_bit(S390_FEAT_AP_FACILITIES_TEST, cpu->model->features);
> +    }
> +
>      check_consistency(cpu->model);
>      check_compatibility(max_model, cpu->model, errp);
>      if (*errp) {
> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
> index 0cdbc15..2d01b52 100644
> --- a/target/s390x/gen-features.c
> +++ b/target/s390x/gen-features.c
> @@ -447,6 +447,9 @@ static uint16_t full_GEN12_GA1[] = {
>      S390_FEAT_ADAPTER_INT_SUPPRESSION,
>      S390_FEAT_EDAT_2,
>      S390_FEAT_SIDE_EFFECT_ACCESS_ESOP2,
> +    S390_FEAT_AP,
> +    S390_FEAT_AP_QUERY_CONFIG_INFO,
> +    S390_FEAT_AP_FACILITIES_TEST,
>  };
>  
>  static uint16_t full_GEN12_GA2[] = {
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index e13c890..ae20ed8 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -2105,6 +2105,7 @@ static int kvm_to_feat[][2] = {
>      { KVM_S390_VM_CPU_FEAT_PFMFI, S390_FEAT_SIE_PFMFI},
>      { KVM_S390_VM_CPU_FEAT_SIGPIF, S390_FEAT_SIE_SIGPIF},
>      { KVM_S390_VM_CPU_FEAT_KSS, S390_FEAT_SIE_KSS},
> +    { KVM_S390_VM_CPU_FEAT_AP, S390_FEAT_AP},
>  };
>  
>  static int query_cpu_feat(S390FeatBitmap features)
> @@ -2214,6 +2215,11 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
>          error_setg(errp, "KVM: Error querying CPU features: %d", rc);
>          return;
>      }
> +    /* AP facilities support is required to enable QCI and APFT support */
> +    if (!test_bit(S390_FEAT_AP, model->features)) {
> +        clear_bit(S390_FEAT_AP_QUERY_CONFIG_INFO, model->features);
> +        clear_bit(S390_FEAT_AP_FACILITIES_TEST, model->features);
> +    }

Hm, do you need this twice?

>      /* get supported cpu subfunctions indicated via query / test bit */
>      rc = query_cpu_subfunc(model->features);
>      if (rc) {

I'm leaving a general review of the cpu model things to David.