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

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Date:   Tue, 16 Aug 2022 11:06:55 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Pierre Morel <pmorel@...ux.ibm.com>, linux-kernel@...r.kernel.org
Cc:     kernel test robot <lkp@...el.com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Eric Farman <farman@...ux.ibm.com>, linux-s390@...r.kernel.org,
        kvm@...r.kernel.org
Subject: Re: [PATCH] vfio-pci/zdev: require KVM to be built-in



On 8/16/22 06:47, Pierre Morel wrote:
> Randy,
> 
> I need to provide the correction patch rapidly.
> Without answer I will propose the patch.
> 
> Regards,
> Pierre

Please go ahead with it.
Thanks.

> 
> On 8/16/22 09:55, Pierre Morel wrote:
>>
>>
>> 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
>>>
>>>
>>
> 

-- 
~Randy