Re: [Qemu-devel] [PATCH 2/6] Remove monitor.c dependency on CONFIG_I8259

[Markus Armbruster]

David Gibson <address@hidden> writes:

> The hmp commands "irq" and "pic" are a bit of a mess.  They're implemented
> on a number of targets, but not all.  On sparc32 and LM32 they do target
> specific things, but on the remainder (i386, ppc and mips) they call into
> the i8259 PIC code.

Where "info pic" does absolutely nothing unless we're using "isa-i8259".
In particular, it does nothing when we're using "kvm-i8259" instead.
Fun!

> But really, what these commands do shouldn't be dependent on the target
> arch, but on the specific machine that's in use.  On ppc, for example,
> the "prep" machine usually does have an ISA bridge with an i8259, but
> most of the other machine types have never had an i8259 at all.  Similarly
> the sparc specific target would stop working if we ever had a sparc32
> machine that wasn't sun4m.
>
> This patch cleans things up by implementing these hmp commands on all
> targets via a MachineClass callback.  If the callback is NULL, for now
> we fallback to target specific defaults that match the existing behaviour.
> The hope is we can remove those later with target specific cleanups.
>
> Signed-off-by: David Gibson <address@hidden>

> ---
>  hw/intc/i8259.c      |  4 ++--
>  include/hw/boards.h  |  2 ++
>  include/hw/i386/pc.h |  4 ++--
>  monitor.c            | 57 
> ++++++++++++++++++++++++++++++++++++++--------------
>  4 files changed, 48 insertions(+), 19 deletions(-)
>
> diff --git a/hw/intc/i8259.c b/hw/intc/i8259.c
> index 0f5c025..43e90b9 100644
> --- a/hw/intc/i8259.c
> +++ b/hw/intc/i8259.c
> @@ -429,7 +429,7 @@ static void pic_realize(DeviceState *dev, Error **errp)
>      pc->parent_realize(dev, errp);
>  }
>  
> -void hmp_info_pic(Monitor *mon, const QDict *qdict)
> +void i8259_hmp_info_pic(Monitor *mon, const QDict *qdict)
>  {
>      int i;
>      PICCommonState *s;
> @@ -447,7 +447,7 @@ void hmp_info_pic(Monitor *mon, const QDict *qdict)
>      }
>  }
>  
> -void hmp_info_irq(Monitor *mon, const QDict *qdict)
> +void i8259_hmp_info_irq(Monitor *mon, const QDict *qdict)
>  {
>  #ifndef DEBUG_IRQ_COUNT
>      monitor_printf(mon, "irq statistic code not compiled.\n");
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 3ddc449..214a778 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -111,6 +111,8 @@ struct MachineClass {
>  
>      HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
>                                             DeviceState *dev);
> +    void (*hmp_info_irq)(Monitor *mon, const QDict *qdict);
> +    void (*hmp_info_pic)(Monitor *mon, const QDict *qdict);
>  };
>  
>  /**

Here you're defining the MachineClass callback.

The callback is designed for HMP.  This will make code implementing it
depend on the monitor.  You could do a QMP-style callback instead, and
get a dependency on QAPI or QObject instead.

But I'm fine with it as is.

> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 08ab67d..0f376c6 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -121,8 +121,8 @@ qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq);
>  qemu_irq *kvm_i8259_init(ISABus *bus);
>  int pic_read_irq(DeviceState *d);
>  int pic_get_output(DeviceState *d);
> -void hmp_info_pic(Monitor *mon, const QDict *qdict);
> -void hmp_info_irq(Monitor *mon, const QDict *qdict);
> +void i8259_hmp_info_pic(Monitor *mon, const QDict *qdict);
> +void i8259_hmp_info_irq(Monitor *mon, const QDict *qdict);
>  
>  /* Global System Interrupts */
>  
> diff --git a/monitor.c b/monitor.c
> index c86a89e..ca226a9 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -1064,6 +1064,48 @@ static void hmp_info_history(Monitor *mon, const QDict 
> *qdict)
>      }
>  }
>  
> +static void hmp_info_pic(Monitor *mon, const QDict *qdict)
> +{
> +    MachineClass *mc = MACHINE_GET_CLASS(current_machine);
> +
> +    if (mc->hmp_info_pic) {
> +        (mc->hmp_info_pic)(mon, qdict);

Here you're using the MachineClass callback.

However, you're not setting it anywhere, so the callback is dead code.

Interfacing to the machine-specific parts with a MachineClass callback
sounds sensible enough, but not without at least one user.  Please
either add one, or drop the dead code for now.

> +    } else {
> +        /* FIXME: Backwards compat fallbacks.  These can go away once
> +         * we've finished converting to natively using MachineClass,
> +         * rather thatn QEMUMachine */
> +#if defined(TARGET_SPARC) && !defined(TARGET_SPARC64)
> +        sun4m_hmp_info_pic(mon, qdict);
> +#elif defined(TARGET_LM32)
> +        lm32_hmp_info_pic(mon, qdict);
> +#elif defined(TARGET_i386) || defined(TARGET_PPC) || defined(TARGET_MIPS)
> +        i8259_hmp_info_pic(mon, qdict);
> +#endif
> +    }
> +}
> +
> +static void hmp_info_irq(Monitor *mon, const QDict *qdict)
> +{
> +    /* FIXME: The ifdefs can go away once the sun4m and LM32 machines
> +     * are converted to use machine classes natively */
> +    MachineClass *mc = MACHINE_GET_CLASS(current_machine);
> +
> +    if (mc->hmp_info_irq) {
> +        (mc->hmp_info_irq)(mon, qdict);
> +    } else {
> +        /* FIXME: Backwards compat fallbacks.  These can go away once
> +         * we've finished converting to natively using MachineClass,
> +         * rather thatn QEMUMachine */
> +#if defined(TARGET_SPARC) && !defined(TARGET_SPARC64)
> +        sun4m_hmp_info_irq(mon, qdict);
> +#elif defined(TARGET_LM32)
> +        lm32_hmp_info_irq(mon, qdict);
> +#elif defined(TARGET_i386) || defined(TARGET_PPC) || defined(TARGET_MIPS)
> +        i8259_hmp_info_irq(mon, qdict);
> +#endif
> +    }
> +}
> +
>  static void hmp_info_cpustats(Monitor *mon, const QDict *qdict)
>  {
>      CPUState *cpu;
> @@ -2661,35 +2703,20 @@ static mon_cmd_t info_cmds[] = {
>          .help       = "show the command line history",
>          .mhandler.cmd = hmp_info_history,
>      },
> -#if defined(TARGET_I386) || defined(TARGET_PPC) || defined(TARGET_MIPS) || \
> -    defined(TARGET_LM32) || (defined(TARGET_SPARC) && 
> !defined(TARGET_SPARC64))
>      {
>          .name       = "irq",
>          .args_type  = "",
>          .params     = "",
>          .help       = "show the interrupts statistics (if available)",
> -#ifdef TARGET_SPARC
> -        .mhandler.cmd = sun4m_hmp_info_irq,
> -#elif defined(TARGET_LM32)
> -        .mhandler.cmd = lm32_hmp_info_irq,
> -#else
>          .mhandler.cmd = hmp_info_irq,
> -#endif
>      },
>      {
>          .name       = "pic",
>          .args_type  = "",
>          .params     = "",
>          .help       = "show i8259 (PIC) state",
> -#ifdef TARGET_SPARC
> -        .mhandler.cmd = sun4m_hmp_info_pic,
> -#elif defined(TARGET_LM32)
> -        .mhandler.cmd = lm32_hmp_info_pic,
> -#else
>          .mhandler.cmd = hmp_info_pic,
> -#endif
>      },
> -#endif
>      {
>          .name       = "pci",
>          .args_type  = "",