thr3ads.net - Linux Virtualization - [PATCH V9 1/9] vhost: refine vhost and vringh kconfig [Apr 2020]

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Jason Wang

2020-Apr-01 14:50 UTC

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

On 2020/4/1 ??10:27, Michael S. Tsirkin wrote:> On Wed, Apr 01, 2020 at 10:13:29PM +0800, Jason Wang wrote:
>> On 2020/4/1 ??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 ??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
> OK I tried this:
>
> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> index 2523a1d4290a..a314b900d479 100644
> --- a/drivers/vhost/Kconfig
> +++ b/drivers/vhost/Kconfig
> @@ -19,11 +19,10 @@ menuconfig VHOST
>   	  This option is selected by any driver which needs to access
>   	  the core of vhost.
>   
> -if VHOST
> -
>   config VHOST_NET
>   	tristate "Host kernel accelerator for virtio net"
>   	depends on NET && EVENTFD && (TUN || !TUN) &&
(TAP || !TAP)
> +	select VHOST
>   	---help---
>   	  This kernel module can be loaded in host kernel to accelerate
>   	  guest networking with virtio_net. Not to be confused with virtio_net
> @@ -35,6 +34,7 @@ config VHOST_NET
>   config VHOST_SCSI
>   	tristate "VHOST_SCSI TCM fabric driver"
>   	depends on TARGET_CORE && EVENTFD
> +	select VHOST
>   	default n
>   	---help---
>   	Say M here to enable the vhost_scsi TCM fabric module
> @@ -44,6 +44,7 @@ config VHOST_VSOCK
>   	tristate "vhost virtio-vsock driver"
>   	depends on VSOCKETS && EVENTFD
>   	select VIRTIO_VSOCKETS_COMMON
> +	select VHOST
>   	default n
>   	---help---
>   	This kernel module can be loaded in the host kernel to provide AF_VSOCK
> @@ -57,6 +58,7 @@ config VHOST_VDPA
>   	tristate "Vhost driver for vDPA-based backend"
>   	depends on EVENTFD
>   	select VDPA
> +	select VHOST
>   	help
>   	  This kernel module can be loaded in host kernel to accelerate
>   	  guest virtio devices with the vDPA-based backends.
> @@ -78,5 +80,3 @@ config VHOST_CROSS_ENDIAN_LEGACY
>   	  adds some overhead, it is disabled by default.
>   
>   	  If unsure, say "N".
> -
> -endif
>
>
> But now CONFIG_VHOST is always "y", never "m".
> Which I think will make it a built-in.
> Didn't figure out why yet.

Is it because the dependency of EVENTFD for CONFIG_VHOST?

Remove that one for this patch, I can get CONFIG_VHOST=m.

But according to documentation/kbuild/kconfig.rst, select is used for 
option without prompt.

Thanks

>

Michael S. Tsirkin

2020-Apr-01 15:57 UTC

head link

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

On Wed, Apr 01, 2020 at 10:50:50PM +0800, Jason Wang
wrote:> 
> On 2020/4/1 ??10:27, Michael S. Tsirkin wrote:
> > On Wed, Apr 01, 2020 at 10:13:29PM +0800, Jason Wang wrote:
> > > On 2020/4/1 ??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 ??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
> > OK I tried this:
> > 
> > diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> > index 2523a1d4290a..a314b900d479 100644
> > --- a/drivers/vhost/Kconfig
> > +++ b/drivers/vhost/Kconfig
> > @@ -19,11 +19,10 @@ menuconfig VHOST
> >   	  This option is selected by any driver which needs to access
> >   	  the core of vhost.
> > -if VHOST
> > -
> >   config VHOST_NET
> >   	tristate "Host kernel accelerator for virtio net"
> >   	depends on NET && EVENTFD && (TUN || !TUN)
&& (TAP || !TAP)
> > +	select VHOST
> >   	---help---
> >   	  This kernel module can be loaded in host kernel to accelerate
> >   	  guest networking with virtio_net. Not to be confused with
virtio_net
> > @@ -35,6 +34,7 @@ config VHOST_NET
> >   config VHOST_SCSI
> >   	tristate "VHOST_SCSI TCM fabric driver"
> >   	depends on TARGET_CORE && EVENTFD
> > +	select VHOST
> >   	default n
> >   	---help---
> >   	Say M here to enable the vhost_scsi TCM fabric module
> > @@ -44,6 +44,7 @@ config VHOST_VSOCK
> >   	tristate "vhost virtio-vsock driver"
> >   	depends on VSOCKETS && EVENTFD
> >   	select VIRTIO_VSOCKETS_COMMON
> > +	select VHOST
> >   	default n
> >   	---help---
> >   	This kernel module can be loaded in the host kernel to provide
AF_VSOCK
> > @@ -57,6 +58,7 @@ config VHOST_VDPA
> >   	tristate "Vhost driver for vDPA-based backend"
> >   	depends on EVENTFD
> >   	select VDPA
> > +	select VHOST
> >   	help
> >   	  This kernel module can be loaded in host kernel to accelerate
> >   	  guest virtio devices with the vDPA-based backends.
> > @@ -78,5 +80,3 @@ config VHOST_CROSS_ENDIAN_LEGACY
> >   	  adds some overhead, it is disabled by default.
> >   	  If unsure, say "N".
> > -
> > -endif
> > 
> > 
> > But now CONFIG_VHOST is always "y", never "m".
> > Which I think will make it a built-in.
> > Didn't figure out why yet.
> 
> 
> Is it because the dependency of EVENTFD for CONFIG_VHOST?
Oh no, it's because I forgot to change menuconfig to config.

> Remove that one for this patch, I can get CONFIG_VHOST=m.
> 
> But according to documentation/kbuild/kconfig.rst, select is used for
option
> without prompt.
> 
> Thanks
> 
> 
> >

Christian Borntraeger

2020-Apr-01 18:53 UTC

head link

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

On 01.04.20 17:57, Michael S. Tsirkin wrote:> On Wed, Apr 01, 2020 at 10:50:50PM +0800, Jason Wang wrote:
>>
>> On 2020/4/1 ??10:27, Michael S. Tsirkin wrote:
>>> On Wed, Apr 01, 2020 at 10:13:29PM +0800, Jason Wang wrote:
>>>> On 2020/4/1 ??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 ??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
>>> OK I tried this:
>>>
>>> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
>>> index 2523a1d4290a..a314b900d479 100644
>>> --- a/drivers/vhost/Kconfig
>>> +++ b/drivers/vhost/Kconfig
>>> @@ -19,11 +19,10 @@ menuconfig VHOST
>>>   	  This option is selected by any driver which needs to access
>>>   	  the core of vhost.
>>> -if VHOST
>>> -
>>>   config VHOST_NET
>>>   	tristate "Host kernel accelerator for virtio net"
>>>   	depends on NET && EVENTFD && (TUN || !TUN)
&& (TAP || !TAP)
>>> +	select VHOST
>>>   	---help---
>>>   	  This kernel module can be loaded in host kernel to accelerate
>>>   	  guest networking with virtio_net. Not to be confused with
virtio_net
>>> @@ -35,6 +34,7 @@ config VHOST_NET
>>>   config VHOST_SCSI
>>>   	tristate "VHOST_SCSI TCM fabric driver"
>>>   	depends on TARGET_CORE && EVENTFD
>>> +	select VHOST
>>>   	default n
>>>   	---help---
>>>   	Say M here to enable the vhost_scsi TCM fabric module
>>> @@ -44,6 +44,7 @@ config VHOST_VSOCK
>>>   	tristate "vhost virtio-vsock driver"
>>>   	depends on VSOCKETS && EVENTFD
>>>   	select VIRTIO_VSOCKETS_COMMON
>>> +	select VHOST
>>>   	default n
>>>   	---help---
>>>   	This kernel module can be loaded in the host kernel to provide
AF_VSOCK
>>> @@ -57,6 +58,7 @@ config VHOST_VDPA
>>>   	tristate "Vhost driver for vDPA-based backend"
>>>   	depends on EVENTFD
>>>   	select VDPA
>>> +	select VHOST
>>>   	help
>>>   	  This kernel module can be loaded in host kernel to accelerate
>>>   	  guest virtio devices with the vDPA-based backends.
>>> @@ -78,5 +80,3 @@ config VHOST_CROSS_ENDIAN_LEGACY
>>>   	  adds some overhead, it is disabled by default.
>>>   	  If unsure, say "N".
>>> -
>>> -endif
>>>
>>>
>>> But now CONFIG_VHOST is always "y", never "m".
>>> Which I think will make it a built-in.
>>> Didn't figure out why yet.
>>
>>
>> Is it because the dependency of EVENTFD for CONFIG_VHOST?
> 
> Oh no, it's because I forgot to change menuconfig to config.
> 
> 
>> Remove that one for this patch, I can get CONFIG_VHOST=m.
FWIW, the current vhost/linux-next branch seems to work again.

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