Re: [Qemu-devel] [PATCH 4/4] Disable "info irq" and "info pic" for target-ppc

[Laurent Vivier <lvivier@redhat.com>]

On 29/06/2015 11:51, Laurent Vivier wrote:
> 
> 
> On 29/06/2015 11:30, Thomas Huth wrote:
>> On Mon, 29 Jun 2015 09:52:56 +0200
>> Laurent Vivier <lvivier@redhat.com> wrote:
>>
>>>
>>>
>>> On 29/06/2015 07:36, David Gibson wrote:
>>>> The "info irq" and "info pic" HMP commands are available on some, but not
>>>> all targets, and what they do isn't terribly consistent.  For SPARC and
>>>> LM32 they do something platform specific, but for x86, powerpc, and MIPS
>>>> they print some information from the i8259 (and only the i8259) interrupt
>>>> controller.
>>>>
>>>> It's debatable whether these commands are any use at all, and we should
>>>> probably make better, qdev aware ways of getting information from a
>>>> machines PICs.  However, those don't exist yet, so on x86 it's at least
>>>> potentially useful to have these HMP commands.  I can't speak for MIPS.
>>>>
>>>> For ppc, though, the i8259, if it exists at all, is usually just a
>>>> secondary controller for legacy ISA.  The only case where i8259 is the
>>>> main system PIC on ppc is for the ancient and little-used PReP platform.
>>>>
>>>> So, even without QOM-ish replacement, the info pic and info irq HMP
>>>> commands have no value on ppc.
>>>>
>>>> This patch, therefore, disables these commands for ppc targets.  This will
>>>> allow ppc builds which don't include PReP to not include ISA bus support
>>>> either.
>>>>
>>>> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
>>>> ---
>>>>  monitor.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/monitor.c b/monitor.c
>>>> index aeea2b5..8c56bfa 100644
>>>> --- a/monitor.c
>>>> +++ b/monitor.c
>>>> @@ -2573,7 +2573,7 @@ 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) || \
>>>> +#if defined(TARGET_I386) || defined(TARGET_MIPS) || \
>>>>      defined(TARGET_LM32) || (defined(TARGET_SPARC) && !defined(TARGET_SPARC64))
>>>>      {
>>>>          .name       = "irq",
>>>>
>>>
>>> Perhaps we can a use a "#if defined(CONFIG_I8259) ||
>>> defined(CONFIG_LM32) || (defined(TARGE_SPARC) &&
>>> !defined(TARGET_SPARC64))" instead, so we keep the command for PReP ?
>>
>> AFAIK this currently won't work since CONFIG_I8259 is only defined for
>> the Makefiles, but not for the C pre-processor :-(
> 
> Yes, I see that afterward, but ...
> 
>> So unless somebody fixes that first, I think David's approach is the
>> only practicable solution right now.
> 
> if you add "config-devices.h" in GENERATED_HEADERS in Makefile.target,
> and include "config-devices.h" in monitor.c, it works (all PREP
> dependencies in default-configs/ppc64-softmmu.mak must be removed too)
> 
> But does this change acceptable for a tiny improvement ?

In fine, I think we can also do like for sparc:

defined(TARGET_PPC) && !defined(TARGET_PPC64)

Laurent