On Wed, Apr 01, 2020 at 10:50:50PM +0800, Jason Wang wrote: > > 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? 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 > > > >
