Re: [PATCH v2] kconfig: Add PCIe devices to s390x machines

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 4/7/23 14:32, Cédric Le Goater wrote:
> On 7/4/23 14:09, Philippe Mathieu-Daudé wrote:
>> On 4/7/23 14:01, Cédric Le Goater wrote:
>>> It is useful to extend the number of available PCI devices to KVM guests
>>> for passthrough scenarios and also to expose these models to a different
>>> (big endian) architecture. Include models for Intel Ethernet adapters
>>> and one USB controller, which all support MSI-X. Devices only supporting
>>> INTx won't work on s390x.
>>>
>>> Signed-off-by: Cédric Le Goater <clg@redhat.com>
>>> ---
>>>
>>>   Tested under KVM as a machine device, under KVM nested as a 
>>> passthrough
>>>   device
>>>
>>>   hw/s390x/Kconfig | 4 ++++
>>>   1 file changed, 4 insertions(+)
>>>
>>> diff --git a/hw/s390x/Kconfig b/hw/s390x/Kconfig
>>> index 5e7d8a2bae8b..7a82c58cdf6e 100644
>>> --- a/hw/s390x/Kconfig
>>> +++ b/hw/s390x/Kconfig
>>> @@ -10,3 +10,7 @@ config S390_CCW_VIRTIO
>>>       select SCLPCONSOLE
>>>       select VIRTIO_CCW
>>>       select MSI_NONBROKEN
>>> +    imply PCI_EXPRESS
>>
>> No, PCIe is a bus, which is implemented in s390-pci-bus.c;
>> S390_CCW_VIRTIO exposes this bus, so we Kconfig SELECT it.
>>
>>> +    imply E1000E_PCI_EXPRESS
>>> +    imply IGB_PCI_EXPRESS
>>> +    imply USB_XHCI_PCI
>>
>> These are devices you can plug on a PCIe bus, so Kconfig
>> IMPLY is correct.
> 
> If I understand correctly, this should be ?
> 
> @@ -5,8 +5,11 @@ config S390_CCW_VIRTIO
>       imply VFIO_AP
>       imply VFIO_CCW
>       imply WDT_DIAG288
> -    select PCI
> +    select PCI_EXPRESS
>       select S390_FLIC
>       select SCLPCONSOLE
>       select VIRTIO_CCW
>       select MSI_NONBROKEN
> +    imply E1000E_PCI_EXPRESS
> +    imply IGB_PCI_EXPRESS
> +    imply USB_XHCI_PCI

This is how I'd write this patch. Note I have zero knowledge of zPCI.