Re: [PATCH V9 1/9] vhost: refine vhost and vringh kconfig

[Jason Wang <jasowang@redhat.com>]

On 2020/4/1 下午9:02, Christian Borntraeger wrote:
>
> On 01.04.20 14:56, Christian Borntraeger wrote:
>> On 01.04.20 14:50, Jason Wang wrote:
>>> On 2020/4/1 下午7:21, Christian Borntraeger wrote:
>>>> On 26.03.20 15:01, Jason Wang wrote:
>>>>> Currently, CONFIG_VHOST depends on CONFIG_VIRTUALIZATION. But vhost is
>>>>> not necessarily for VM since it's a generic userspace and kernel
>>>>> communication protocol. Such dependency may prevent archs without
>>>>> virtualization support from using vhost.
>>>>>
>>>>> To solve this, a dedicated vhost menu is created under drivers so
>>>>> CONIFG_VHOST can be decoupled out of CONFIG_VIRTUALIZATION.
>>>> FWIW, this now results in vhost not being build with defconfig kernels (in todays
>>>> linux-next).
>>>>
>>> Hi Christian:
>>>
>>> Did you meet it even with this commit https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=a4be40cbcedba9b5b714f3c95182e8a45176e42d?
>> I simply used linux-next. The defconfig does NOT contain CONFIG_VHOST and therefore CONFIG_VHOST_NET and friends
>> can not be selected.
>>
>> $ git checkout next-20200401
>> $ make defconfig
>>    HOSTCC  scripts/basic/fixdep
>>    HOSTCC  scripts/kconfig/conf.o
>>    HOSTCC  scripts/kconfig/confdata.o
>>    HOSTCC  scripts/kconfig/expr.o
>>    LEX     scripts/kconfig/lexer.lex.c
>>    YACC    scripts/kconfig/parser.tab.[ch]
>>    HOSTCC  scripts/kconfig/lexer.lex.o
>>    HOSTCC  scripts/kconfig/parser.tab.o
>>    HOSTCC  scripts/kconfig/preprocess.o
>>    HOSTCC  scripts/kconfig/symbol.o
>>    HOSTCC  scripts/kconfig/util.o
>>    HOSTLD  scripts/kconfig/conf
>> *** Default configuration is based on 'x86_64_defconfig'
>> #
>> # configuration written to .config
>> #
>>
>> $ grep VHOST .config
>> # CONFIG_VHOST is not set
>>
>>   
>>> If yes, what's your build config looks like?
>>>
>>> Thanks
> This was x86. Not sure if that did work before.
> On s390 this is definitely a regression as the defconfig files
> for s390 do select VHOST_NET
>
> grep VHOST arch/s390/configs/*
> arch/s390/configs/debug_defconfig:CONFIG_VHOST_NET=m
> arch/s390/configs/debug_defconfig:CONFIG_VHOST_VSOCK=m
> arch/s390/configs/defconfig:CONFIG_VHOST_NET=m
> arch/s390/configs/defconfig:CONFIG_VHOST_VSOCK=m
>
> and this worked with 5.6, but does not work with next. Just adding
> CONFIG_VHOST=m to the defconfig solves the issue, something like


Right, I think we probably need

1) add CONFIG_VHOST=m to all defconfigs that enables 
CONFIG_VHOST_NET/VSOCK/SCSI.

or

2) don't use menuconfig for CONFIG_VHOST, let NET/SCSI/VDPA just select it.

Thanks


>
> ---
>   arch/s390/configs/debug_defconfig | 5 +++--
>   arch/s390/configs/defconfig       | 5 +++--
>   2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/configs/debug_defconfig b/arch/s390/configs/debug_defconfig
> index 46038bc58c9e..0b83274341ce 100644
> --- a/arch/s390/configs/debug_defconfig
> +++ b/arch/s390/configs/debug_defconfig
> @@ -57,8 +57,6 @@ CONFIG_PROTECTED_VIRTUALIZATION_GUEST=y
>   CONFIG_CMM=m
>   CONFIG_APPLDATA_BASE=y
>   CONFIG_KVM=m
> -CONFIG_VHOST_NET=m
> -CONFIG_VHOST_VSOCK=m
>   CONFIG_OPROFILE=m
>   CONFIG_KPROBES=y
>   CONFIG_JUMP_LABEL=y
> @@ -561,6 +559,9 @@ CONFIG_VFIO_MDEV_DEVICE=m
>   CONFIG_VIRTIO_PCI=m
>   CONFIG_VIRTIO_BALLOON=m
>   CONFIG_VIRTIO_INPUT=y
> +CONFIG_VHOST=m
> +CONFIG_VHOST_NET=m
> +CONFIG_VHOST_VSOCK=m
>   CONFIG_S390_CCW_IOMMU=y
>   CONFIG_S390_AP_IOMMU=y
>   CONFIG_EXT4_FS=y
> diff --git a/arch/s390/configs/defconfig b/arch/s390/configs/defconfig
> index 7cd0648c1f4e..39e69c4e8cf7 100644
> --- a/arch/s390/configs/defconfig
> +++ b/arch/s390/configs/defconfig
> @@ -57,8 +57,6 @@ CONFIG_PROTECTED_VIRTUALIZATION_GUEST=y
>   CONFIG_CMM=m
>   CONFIG_APPLDATA_BASE=y
>   CONFIG_KVM=m
> -CONFIG_VHOST_NET=m
> -CONFIG_VHOST_VSOCK=m
>   CONFIG_OPROFILE=m
>   CONFIG_KPROBES=y
>   CONFIG_JUMP_LABEL=y
> @@ -557,6 +555,9 @@ CONFIG_VFIO_MDEV_DEVICE=m
>   CONFIG_VIRTIO_PCI=m
>   CONFIG_VIRTIO_BALLOON=m
>   CONFIG_VIRTIO_INPUT=y
> +CONFIG_VHOST=m
> +CONFIG_VHOST_NET=m
> +CONFIG_VHOST_VSOCK=m
>   CONFIG_S390_CCW_IOMMU=y
>   CONFIG_S390_AP_IOMMU=y
>   CONFIG_EXT4_FS=y