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

[Christian Borntraeger <borntraeger@de.ibm.com>]

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

---
 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
-- 
2.25.1