Messages in this thread | | | Subject | Re: [PATCH V9 1/9] vhost: refine vhost and vringh kconfig | From | Jason Wang <> | Date | Wed, 1 Apr 2020 22:50:50 +0800 |
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On 2020/4/1 下午10:27, Michael S. Tsirkin wrote: > On Wed, Apr 01, 2020 at 10:13:29PM +0800, Jason Wang wrote: >> 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 > 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
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