Re: [Qemu-devel] [PATCH 3/4] RFC target/arm: Do not build pre-ARMv7 cpus when using KVM

[Thomas Huth <thuth@redhat.com>]

On 29/08/2019 20.19, Philippe Mathieu-Daudé wrote:
> Hi Thomas,
> 
> On 8/23/19 4:28 PM, Thomas Huth wrote:
>> On 8/23/19 3:58 PM, Philippe Mathieu-Daudé wrote:
>>> A KVM-only build won't be able to run pre-ARMv7 cpus, disable them.
>>>
>>> If KVM is not enabled, they are enabled by default.
>> [...]
>>>  config CHEETAH
>>>      bool
>>> +    select ARM_V4
>>>      select OMAP
>>>      select TSC210X
>>
>> Are you sure about the "enabled by default" ? There is not "default y"
>> here, is it?
> 
> What I mean is if you build with --disable-kvm, this selects
> --enable-tcg which provides the pre-ARMv7 cpus. So to make no changes, I
> also added:
> 
>   config ARM_V4
>       default y
> 
> Which include the "default y".

Well, so the ARM_V4 config switch is enabled by default. But where is
the CHEETAH config switch enabled now?

>> I think we should maybe rather rework the default-configs directory:
>> Rename the default to "config/default/" instead and then we can add
>> other subfolders with such special configurations, e.g. config/nemu/ or
>> config/lean-kvm/ or however you want to call it. Then add a new switch
>> to the configure script to be able to use the configs from such a
>> different folder.
> 
> OK so if someone wants a special config, he'd know the config values to
> select, so it is pointless/confusing to keep them commented.
> Are you suggesting to simply remove the default entries?
Certainly not! I meant to keep the current file (with everything
enabled) in config/default/, and to add another config file to
config/lean-kvm/ where the TCG-only boards are disabled. Then the user
can easily run "./configure --build-config-dir=config/lean-kvm/" to
enable these settings.

 Thomas