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. -- MST
