Re: [PATCH] vfio-pci/zdev: require KVM to be built-in

Pierre Morel
2022-08-16T09:30:53Z

On 8/16/22 08:04, Randy Dunlap wrote:
> Hi--
>
> On 8/15/22 02:43, Pierre Morel wrote:
>> Thank you Randy for this good catch.
>> However forcing KVM to be include statically in the kernel when using VFIO_PCI extensions is not a good solution for us I think.
>>
>> I suggest we better do something like:
>>
>> ----
>>
>> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
>> index 6287a843e8bc..1733339cc4eb 100644
>> --- a/arch/s390/include/asm/kvm_host.h
>> +++ b/arch/s390/include/asm/kvm_host.h
>> @@ -1038,7 +1038,7 @@ static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
>>  #define __KVM_HAVE_ARCH_VM_FREE
>>  void kvm_arch_free_vm(struct kvm *kvm);
>>
>> -#ifdef CONFIG_VFIO_PCI_ZDEV_KVM
>> +#if defined(CONFIG_VFIO_PCI_ZDEV_KVM) || defined(CONFIG_VFIO_PCI_ZDEV_KVM_MODULE)
>
> This all looks good except for the line above.
> It should be:
>
> #if IS_ENABLED(CONFIG_VFIO_PCI_ZDEV_KVM)
>
> Thanks.

Yes, better, thanks.
How do we do? Should I repost it with reported-by you or do you want to
post it?

Pierre

>
>
>>  int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm);
>>  void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev);
>>  #else
>> diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig
>> index f9d0c908e738..bbc375b028ef 100644
>> --- a/drivers/vfio/pci/Kconfig
>> +++ b/drivers/vfio/pci/Kconfig
>> @@ -45,9 +45,9 @@ config VFIO_PCI_IGD
>>  endif
>>
>>  config VFIO_PCI_ZDEV_KVM
>> -       bool "VFIO PCI extensions for s390x KVM passthrough"
>> +       def_tristate y
>> +       prompt "VFIO PCI extensions for s390x KVM passthrough"
>>         depends on S390 && KVM
>> -       default y
>>         help
>>           Support s390x-specific extensions to enable support for enhancements
>>           to KVM passthrough capabilities, such as interpretive execution of
>>
>> ----
>>
>> What do you think? It seems to me it solves the problem, what do you think?
>>
>> Regards,
>> Pierre
>
>

--
Pierre Morel
IBM Lab Boeblingen