Re: [PATCH 01/10] hw/mem/nvdimm: Use Kconfig 'imply' instead of 'depends on'

[Philippe Mathieu-Daudé]

On 5/16/21 2:50 AM, Bin Meng wrote:
> On Sun, May 16, 2021 at 1:33 AM Philippe Mathieu-Daudé
> <philmd@redhat.com> wrote:
>>
>> On 5/14/21 5:02 AM, Bin Meng wrote:
>>> On Fri, May 14, 2021 at 12:53 AM Philippe Mathieu-Daudé
>>> <philmd@redhat.com> wrote:
>>>>
>>>> Per the kconfig.rst:
>>>>
>>>>   A device should be listed [...] ``imply`` if (depending on
>>>>   the QEMU command line) the board may or  may not be started
>>>>   without it.
>>>>
>>>> This is the case with the NVDIMM device (it is certainly possible
>>>> to start a machine without NVDIMM) , so use the 'imply' weak
>>>> reverse dependency to select the symbol.
>>>>
>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>> ---
>>>>  default-configs/devices/ppc64-softmmu.mak | 1 -
>>>>  hw/arm/Kconfig                            | 1 +
>>>>  hw/i386/Kconfig                           | 1 +
>>>>  hw/mem/Kconfig                            | 2 --
>>>>  hw/ppc/Kconfig                            | 1 +
>>>>  5 files changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/default-configs/devices/ppc64-softmmu.mak 
>>>> b/default-configs/devices/ppc64-softmmu.mak
>>>> index ae0841fa3a1..cca52665d90 100644
>>>> --- a/default-configs/devices/ppc64-softmmu.mak
>>>> +++ b/default-configs/devices/ppc64-softmmu.mak
>>>> @@ -8,4 +8,3 @@ CONFIG_POWERNV=y
>>>>
>>>>  # For pSeries
>>>>  CONFIG_PSERIES=y
>>>> -CONFIG_NVDIMM=y
>>>
>>> I think only removing this one makes sense. I fail to see any
>>> difference of other changes in this patch.
>>
>> See below "depends on (PC || PSERIES || ARM_VIRT)"
> 
> Yes, I saw that. This change does not make any difference compared to
> "depends on"

No, there is no logical change indeed. Simply IIUC the documentation
"imply" is the preferred form.

> 
>>
>>>
>>>> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
>>>> index b887f6a5b17..67723d9ea6a 100644
>>>> --- a/hw/arm/Kconfig
>>>> +++ b/hw/arm/Kconfig
>>>> @@ -6,6 +6,7 @@ config ARM_VIRT
>>>>      imply VFIO_PLATFORM
>>>>      imply VFIO_XGMAC
>>>>      imply TPM_TIS_SYSBUS
>>>> +    imply NVDIMM
>>>>      select ARM_GIC
>>>>      select ACPI
>>>>      select ARM_SMMUV3
>>>> diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
>>>> index 7f91f30877f..66838fa397b 100644
>>>> --- a/hw/i386/Kconfig
>>>> +++ b/hw/i386/Kconfig
>>>> @@ -23,6 +23,7 @@ config PC
>>>>      imply TPM_TIS_ISA
>>>>      imply VGA_PCI
>>>>      imply VIRTIO_VGA
>>>> +    imply NVDIMM
>>>>      select FDC
>>>>      select I8259
>>>>      select I8254
>>>> diff --git a/hw/mem/Kconfig b/hw/mem/Kconfig
>>>> index a0ef2cf648e..8b19fdc49f1 100644
>>>> --- a/hw/mem/Kconfig
>>>> +++ b/hw/mem/Kconfig
>>>> @@ -7,6 +7,4 @@ config MEM_DEVICE
>>>>
>>>>  config NVDIMM
>>>>      bool
>>>> -    default y
>>>> -    depends on (PC || PSERIES || ARM_VIRT)
>>>>      select MEM_DEVICE
>>>> diff --git a/hw/ppc/Kconfig b/hw/ppc/Kconfig
>>>> index e51e0e5e5ac..66e0b15d9ef 100644
>>>> --- a/hw/ppc/Kconfig
>>>> +++ b/hw/ppc/Kconfig
>>>> @@ -3,6 +3,7 @@ config PSERIES
>>>>      imply PCI_DEVICES
>>>>      imply TEST_DEVICES
>>>>      imply VIRTIO_VGA
>>>> +    imply NVDIMM
>>>>      select DIMM
>>>>      select PCI
>>>>      select SPAPR_VSCSI
> 
> Regards,
> Bin
>