Linux Virtualization - Dec 2017 - [PATCH] virtio: make VIRTIO a menuconfig to ease disabling it all

No need to get into the submenu to disable all VIRTIO-related
config entries.

This makes it easier to disable all VIRTIO config options
without entering the submenu. It will also enable one
to see that en/dis-abled state from the outside menu.

This is only intended to change menuconfig UI, not change
the config dependencies.

Signed-off-by: Vincent Legoll <vincent.legoll at gmail.com>
---
 drivers/virtio/Kconfig | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index cff773f15b7e..d485a63a8233 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -5,7 +5,10 @@ config VIRTIO
 	  bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
 	  or CONFIG_S390_GUEST.
 
-menu "Virtio drivers"
+menuconfig VIRTIO_MENU
+	bool "Virtio drivers"
+
+if VIRTIO_MENU
 
 config VIRTIO_PCI
 	tristate "PCI driver for virtio devices"
@@ -79,4 +82,4 @@ config VIRTIO_MMIO_CMDLINE_DEVICES
 
 	 If unsure, say 'N'.
 
-endmenu
+endif # VIRTIO_MENU
-- 
2.14.1

On Sat, Dec 09, 2017 at 04:26:57PM +0100, Vincent Legoll
wrote:
> No need to get into the submenu to disable all VIRTIO-related
> config entries.
> 
> This makes it easier to disable all VIRTIO config options
> without entering the submenu. It will also enable one
> to see that en/dis-abled state from the outside menu.
> 
> This is only intended to change menuconfig UI, not change
> the config dependencies.
> 
> Signed-off-by: Vincent Legoll <vincent.legoll at gmail.com>
> ---
>  drivers/virtio/Kconfig | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index cff773f15b7e..d485a63a8233 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -5,7 +5,10 @@ config VIRTIO
>  	  bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
>  	  or CONFIG_S390_GUEST.
>  
> -menu "Virtio drivers"
> +menuconfig VIRTIO_MENU
> +	bool "Virtio drivers"
Hi Vincent,

make localyesconfig and make localmodconfig doesn't work with this
patch.

My scenario looks like this:
* Create a virtual machine with Ubuntu 14.04 in GCE
* git clone git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
* cd linux-next
* curl -o .config
https://raw.githubusercontent.com/avagin/criu/linux-next/scripts/linux-next-config
* make localyesconfig

Without this patch:

$ cat .config | grep VIRTIO
CONFIG_BLK_MQ_VIRTIO=y
CONFIG_VIRTIO_BLK=y
# CONFIG_VIRTIO_BLK_SCSI is not set
CONFIG_SCSI_VIRTIO=y
CONFIG_VIRTIO_NET=y
CONFIG_VIRTIO_CONSOLE=y
# CONFIG_HW_RANDOM_VIRTIO is not set
CONFIG_VIRTIO=y
CONFIG_VIRTIO_PCI=y
CONFIG_VIRTIO_PCI_LEGACY=y
CONFIG_VIRTIO_BALLOON=y
# CONFIG_VIRTIO_INPUT is not set
CONFIG_VIRTIO_MMIO=y
CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES=y
# CONFIG_RPMSG_VIRTIO is not set
# CONFIG_CRYPTO_DEV_VIRTIO is not set


With this patch:

$ cat .config | grep VIRTIO
CONFIG_BLK_MQ_VIRTIO=y
# CONFIG_VIRTIO_BLK is not set
CONFIG_SCSI_VIRTIO=y
# CONFIG_VIRTIO_NET is not set
CONFIG_CAIF_VIRTIO=y
# CONFIG_VIRTIO_CONSOLE is not set
# CONFIG_HW_RANDOM_VIRTIO is not set
CONFIG_VIRTIO=y
# CONFIG_VIRTIO_MENU is not set
# CONFIG_RPMSG_VIRTIO is not set
# CONFIG_CRYPTO_DEV_VIRTIO is not set


You can see that with this patch CONFIG_VIRTIO_BLK is not set.
It is wrong, and the kernel with this config will not be able to boot.

We can add "default y" to fix this problem.

https://travis-ci.org/avagin/linux/jobs/313348334
https://travis-ci.org/avagin/linux/jobs/318491188

Thanks,
Andrei
> +
> +if VIRTIO_MENU
>  
>  config VIRTIO_PCI
>  	tristate "PCI driver for virtio devices"
> @@ -79,4 +82,4 @@ config VIRTIO_MMIO_CMDLINE_DEVICES
>  
>  	 If unsure, say 'N'.
>  
> -endmenu
> +endif # VIRTIO_MENU

Vincent Legoll <vincent.legoll at gmail.com> writes:
> No need to get into the submenu to disable all VIRTIO-related
> config entries.
>
> This makes it easier to disable all VIRTIO config options
> without entering the submenu. It will also enable one
> to see that en/dis-abled state from the outside menu.
>
> This is only intended to change menuconfig UI, not change
> the config dependencies.
>
> Signed-off-by: Vincent Legoll <vincent.legoll at gmail.com>
> ---
>  drivers/virtio/Kconfig | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index cff773f15b7e..d485a63a8233 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -5,7 +5,10 @@ config VIRTIO
>  	  bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
>  	  or CONFIG_S390_GUEST.
>  
> -menu "Virtio drivers"
> +menuconfig VIRTIO_MENU
> +	bool "Virtio drivers"
> +
> +if VIRTIO_MENU
This breaks all existing .configs *and* defconfigs that use VIRTIO.

Please don't do that.

If you make it default y then everything will continue to work.

cheers


diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index d485a63a8233..35897649c24f 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -7,6 +7,7 @@ config VIRTIO
 
 menuconfig VIRTIO_MENU
 	bool "Virtio drivers"
+	default y
 
 if VIRTIO_MENU

Hello,

thanks for the help, and sorry for the poor patch,

On Thu, Dec 21, 2017 at 11:53 AM, Michael Ellerman <mpe at ellerman.id.au>
wrote:
> This breaks all existing .configs *and* defconfigs that use VIRTIO.
>
> Please don't do that.
>
> If you make it default y then everything will continue to work.
Do you want me to respin it with the added default ?

Tchuss

-- 
Vincent Legoll