Re: [Qemu-devel] [PATCH v6 2/4] target-s390x: Migrate to new NMI interface

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Thu, 12 Jun 2014 03:03:01 +1000
Alexey Kardashevskiy <aik@ozlabs.ru> wrote:

> This implements an NMI interface for s390 machine.
> 
> This removes #ifdef s390 branch in qmp_inject_nmi so new s390's
> nmi_monitor_handler() callback is going to be used for NMI.
> 
> Since nmi_monitor_handler()-calling code is platform independent,
> CPUState::cpu_index is used instead of S390CPU::env.cpu_num.
> There should not be any change in behaviour as both @cpu_index and
> @cpu_num are global CPU numbers.
> 
> Also, s390_cpu_restart() takes care of preforming operations in
> the specific CPU thread so no extra measure is required here either.
> 
> Since the only error s390_cpu_restart() can return is ENOSYS, convert
> it to QERR_UNSUPPORTED.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> Changes:
> v6:
> * supported NMI interface
> 
> v5:
> * added ENOSYS -> QERR_UNSUPPORTED, qapi/qmp/qerror.h was added for this
> 
> v4:
> * s/\<nmi\>/nmi_monitor_handler/
> 
> v3:
> * now contains both old code removal and new code insertion, easier to
> track changes
> 
> ---
> Is there any good reason to have @cpu_num in addition to @cpu_index?
> Just asking :)
> ---
>  cpus.c                 | 14 --------------
>  hw/s390x/s390-virtio.c | 31 +++++++++++++++++++++++++++++++
>  target-s390x/cpu.c     |  1 +
>  3 files changed, 32 insertions(+), 14 deletions(-)
> 

> diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
> index 93c7ace..9c5b7b2 100644
> --- a/hw/s390x/s390-virtio.c
> +++ b/hw/s390x/s390-virtio.c
> @@ -38,6 +38,7 @@
>  #include "hw/s390x/sclp.h"
>  #include "hw/s390x/s390_flic.h"
>  #include "hw/s390x/s390-virtio.h"
> +#include "hw/nmi.h"
> 
>  //#define DEBUG_S390
> 
> @@ -51,6 +52,7 @@
> 
>  #define MAX_BLK_DEVS                    10
>  #define ZIPL_FILENAME                   "s390-zipl.rom"
> +#define TYPE_NMI_S390                   "s390_nmi"

I'd prefer "s390-nmi" instead.

> 
>  static VirtIOS390Bus *s390_bus;
>  static S390CPU **ipi_states;
> @@ -277,6 +279,9 @@ static void s390_init(MachineState *machine)
> 
>      /* Create VirtIO network adapters */
>      s390_create_virtio_net((BusState *)s390_bus, "virtio-net-s390");
> +
> +    object_property_add_child(OBJECT(machine), "nmi",
> +                              object_new(TYPE_NMI_S390), NULL);

This only adds the nmi interface to the old s390-virtio machine; we
want this for the s390-virtio-ccw machine as well.

>  }
> 
>  static QEMUMachine s390_machine = {
> @@ -295,8 +300,34 @@ static QEMUMachine s390_machine = {
>      .is_default = 1,
>  };
> 
> +static void s390_nmi(NMI *n, int cpu_index, Error **errp)
> +{
> +    CPUState *cs = qemu_get_cpu(cpu_index);
> +
> +    if (s390_cpu_restart(S390_CPU(cs))) {
> +        error_set(errp, QERR_UNSUPPORTED);
> +    }
> +}
> +
> +static void s390_nmi_class_init(ObjectClass *oc, void *data)
> +{
> +    NMIClass *nc = NMI_CLASS(oc);
> +    nc->nmi_monitor_handler = s390_nmi;
> +}
> +
> +static const TypeInfo s390_nmi_info = {
> +    .name          = TYPE_NMI_S390,
> +    .parent        = TYPE_OBJECT,
> +    .class_init    = s390_nmi_class_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_NMI },
> +        { }
> +    },
> +};
> +
>  static void s390_machine_init(void)
>  {
> +    type_register_static(&s390_nmi_info);

s390-virtio-ccw needs this as well.

>      qemu_register_machine(&s390_machine);
>  }

The best way would probably be to put all nmi-related things into a new
file that registers the nmi type and provides an s390_register_nmi()
helper.

> 
> diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
> index c3082b7..15142ff 100644
> --- a/target-s390x/cpu.c
> +++ b/target-s390x/cpu.c
> @@ -27,6 +27,7 @@
>  #include "qemu-common.h"
>  #include "qemu/timer.h"
>  #include "hw/hw.h"
> +#include "qapi/qmp/qerror.h"

Leftover?

>  #ifndef CONFIG_USER_ONLY
>  #include "sysemu/arch_init.h"
>  #endif