Re: [PATCH v6 2/2] s390: diagnose 318 info reset and migration support

[David Hildenbrand <david@redhat.com>]

[...]
> @@ -0,0 +1,85 @@
> +/*
> + * DIAGNOSE 0x318 functions for reset and migration
> + *
> + * Copyright IBM, Corp. 2019

Should be 2020 now.

[...]
> +static void s390_diag318_reset(DeviceState *dev)
> +{
> +    if (kvm_enabled())
> +        kvm_s390_set_diag318_info(0);
> +}
> +
> +static void s390_diag318_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->reset = s390_diag318_reset;
> +    dc->vmsd = &vmstate_diag318;
> +    dc->hotpluggable = false;
> +    /* Reason: Created automatically during machine instantiation */
> +    dc->user_creatable = false;
> +}
> +
> +static const TypeInfo s390_diag318_info = {
> +    .class_init = s390_diag318_class_init,
> +    .parent = TYPE_DEVICE,
> +    .name = TYPE_S390_DIAG318,
> +    .instance_size = sizeof(DIAG318State),
> +};
> +
> +static void s390_diag318_register_types(void)
> +{
> +    type_register_static(&s390_diag318_info);
> +}

Do we really need a new device? Can't we simply glue that extended state
to the machine state?

-> target/s390x/machine.c

> +
> +type_init(s390_diag318_register_types)
> diff --git a/hw/s390x/diag318.h b/hw/s390x/diag318.h
> new file mode 100644
> index 0000000..06d9f67
> --- /dev/null
> +++ b/hw/s390x/diag318.h
> @@ -0,0 +1,40 @@
> +/*
> + * DIAGNOSE 0x318 functions for reset and migration
> + *
> + * Copyright IBM, Corp. 2019
> + *
> + * Authors:
> + *  Collin Walling <walling@linux.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or (at your
> + * option) any later version. See the COPYING file in the top-level directory.
> + */
> +
> +#ifndef HW_DIAG318_H
> +#define HW_DIAG318_H
> +
> +#include "qemu/osdep.h"
> +#include "migration/vmstate.h"
> +#include "qom/object.h"
> +#include "hw/qdev-core.h"
> +
> +#define TYPE_S390_DIAG318 "diag318"
> +#define DIAG318(obj) \
> +    OBJECT_CHECK(DIAG318State, (obj), TYPE_S390_DIAG318)
> +
> +typedef struct DIAG318State {
> +    /*< private >*/
> +    DeviceState parent_obj;
> +
> +    /*< public >*/
> +    uint64_t info;
> +} DIAG318State;
> +
> +typedef struct DIAG318Class {
> +    /*< private >*/
> +    DeviceClass parent_class;
> +
> +    /*< public >*/
> +} DIAG318Class;
> +
> +#endif /* HW_DIAG318_H */
> \ No newline at end of file
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index e0e2813..d5b7a33 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -41,6 +41,7 @@
>  #include "hw/qdev-properties.h"
>  #include "hw/s390x/tod.h"
>  #include "sysemu/sysemu.h"
> +#include "hw/s390x/diag318.h"
>  
>  S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
>  {
> @@ -97,6 +98,7 @@ static const char *const reset_dev_types[] = {
>      "s390-sclp-event-facility",
>      "s390-flic",
>      "diag288",
> +    TYPE_S390_DIAG318,
>  };
>  
>  static void subsystem_reset(void)
> @@ -237,6 +239,17 @@ static void s390_create_sclpconsole(const char *type, Chardev *chardev)
>      qdev_init_nofail(dev);
>  }
>  
> +static void s390_init_diag318(void)
> +{
> +    Object *new = object_new(TYPE_S390_DIAG318);
> +    DeviceState *dev = DEVICE(new);
> +
> +    object_property_add_child(qdev_get_machine(), TYPE_S390_DIAG318,
> +                              new, NULL);
> +    object_unref(new);
> +    qdev_init_nofail(dev);
> +}
> +
>  static void ccw_init(MachineState *machine)
>  {
>      int ret;
> @@ -294,6 +307,9 @@ static void ccw_init(MachineState *machine)
>  
>      /* init the TOD clock */
>      s390_init_tod();
> +
> +    /* init object used for migrating diag318 info */
> +    s390_init_diag318();
>  }
>  
>  static void s390_cpu_plug(HotplugHandler *hotplug_dev,
> @@ -566,6 +582,7 @@ static void machine_set_loadparm(Object *obj, const char *val, Error **errp)
>          ms->loadparm[i] = ' '; /* pad right with spaces */
>      }
>  }
> +

unrelated change.

>  static inline void s390_machine_initfn(Object *obj)
>  {
>      object_property_add_bool(obj, "aes-key-wrap",
> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
> index f57ce7b..636348c 100644
> --- a/hw/s390x/sclp.c
> +++ b/hw/s390x/sclp.c
> @@ -15,6 +15,7 @@
>  #include "qemu/osdep.h"
>  #include "qemu/units.h"
>  #include "qapi/error.h"
> +#include "qemu/error-report.h"
>  #include "cpu.h"
>  #include "sysemu/sysemu.h"
>  #include "hw/boards.h"
> @@ -22,6 +23,7 @@
>  #include "hw/s390x/event-facility.h"
>  #include "hw/s390x/s390-pci-bus.h"
>  #include "hw/s390x/ipl.h"
> +#include "kvm_s390x.h"
>  
>  static inline SCLPDevice *get_sclp_device(void)
>  {
> @@ -37,10 +39,19 @@ static void prepare_cpu_entries(SCLPDevice *sclp, CPUEntry *entry, int *count)
>  {
>      MachineState *ms = MACHINE(qdev_get_machine());
>      uint8_t features[SCCB_CPU_FEATURE_LEN] = { 0 };
> +    int max_entries;
>      int i;
>  
> +    /* Calculate the max number of CPU entries that can be stored in the SCCB */
> +    max_entries = (SCCB_SIZE - offsetof(ReadInfo, entries)) / sizeof(CPUEntry);
> +
>      s390_get_feat_block(S390_FEAT_TYPE_SCLP_CPU, features);
>      for (i = 0, *count = 0; i < ms->possible_cpus->len; i++) {
> +        if (*count == max_entries) {
> +            warn_report("Configuration only supports a max of %d CPU entries.",
> +                        max_entries);

I remember that "the sclp response will be limited to 247 CPUs if the
feature is one". So we should have a double layout and make max_entries
depending on s390_has_feat().

Regarding the message, I'd probably do a "Due to the current CPU model,
some CPUs might be hidden from the VM (SCLP)."

A VM could still manually probe for others.

Thanks!

-- 
Thanks,

David / dhildenb