Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Dongsheng Song]

On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
>
> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> while now and is almost always enabled by default. As agreed during the
> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  arch/x86/xen/Kconfig |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index 93ff4e1..8cada4c 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
>
>  config XEN_X86_PVH
>         bool "Support for running as a PVH guest (EXPERIMENTAL)"

Why not remove this 'EXPERIMENTAL' too ?

> -       depends on X86_64 && XEN && EXPERIMENTAL
> +       depends on X86_64 && XEN
>         default n
>         help
>            This option enables support for running as a PVH guest (PV guest
> --
> 1.7.9.5
>
>
> --
> Kees Cook
> Chrome OS Security
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Kees Cook]

On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
<dongsheng.song@gmail.com> wrote:
> On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
>>
>> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
>> while now and is almost always enabled by default. As agreed during the
>> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
>>
>> Signed-off-by: Kees Cook <keescook@chromium.org>
>> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>> ---
>>  arch/x86/xen/Kconfig |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
>> index 93ff4e1..8cada4c 100644
>> --- a/arch/x86/xen/Kconfig
>> +++ b/arch/x86/xen/Kconfig
>> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
>>
>>  config XEN_X86_PVH
>>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
>
> Why not remove this 'EXPERIMENTAL' too ?

It was unclear to me if the feature was actually considered unstable.
I can resend with the text removed from the title too, if that's the
correct action here?

-Kees

>
>> -       depends on X86_64 && XEN && EXPERIMENTAL
>> +       depends on X86_64 && XEN
>>         default n
>>         help
>>            This option enables support for running as a PVH guest (PV guest
>> --
>> 1.7.9.5
>>
>>
>> --
>> Kees Cook
>> Chrome OS Security
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/



-- 
Kees Cook
Chrome OS Security

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Konrad Rzeszutek Wilk]

On Sat, Feb 23, 2013 at 09:03:20AM -0800, Kees Cook wrote:
> On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> <dongsheng.song@gmail.com> wrote:
> > On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> >>
> >> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> >> while now and is almost always enabled by default. As agreed during the
> >> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> >>
> >> Signed-off-by: Kees Cook <keescook@chromium.org>
> >> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> >> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> >> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> >> ---
> >>  arch/x86/xen/Kconfig |    2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> >> index 93ff4e1..8cada4c 100644
> >> --- a/arch/x86/xen/Kconfig
> >> +++ b/arch/x86/xen/Kconfig
> >> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> >>
> >>  config XEN_X86_PVH
> >>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> >
> > Why not remove this 'EXPERIMENTAL' too ?
> 
> It was unclear to me if the feature was actually considered unstable.
> I can resend with the text removed from the title too, if that's the
> correct action here?

It certainly is unstable right now (which is why it was unstaged from
the v3.9 train). I hope that by v3.10 it won't be - at which
point this patch (and the EXPERIMENTAL) makes sense.

So could you respin it please with the text removed as well - and I will
queue it up in the branch that carries the PVH feature?

Thanks!
> 
> -Kees
> 
> >
> >> -       depends on X86_64 && XEN && EXPERIMENTAL
> >> +       depends on X86_64 && XEN
> >>         default n
> >>         help
> >>            This option enables support for running as a PVH guest (PV guest
> >> --
> >> 1.7.9.5
> >>
> >>
> >> --
> >> Kees Cook
> >> Chrome OS Security
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >> Please read the FAQ at  http://www.tux.org/lkml/
> 
> 
> 
> -- 
> Kees Cook
> Chrome OS Security

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Stefano Stabellini]

On Sat, 23 Feb 2013, Konrad Rzeszutek Wilk wrote:
> On Sat, Feb 23, 2013 at 09:03:20AM -0800, Kees Cook wrote:
> > On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> > <dongsheng.song@gmail.com> wrote:
> > > On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> > >>
> > >> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> > >> while now and is almost always enabled by default. As agreed during the
> > >> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> > >>
> > >> Signed-off-by: Kees Cook <keescook@chromium.org>
> > >> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > >> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> > >> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > >> ---
> > >>  arch/x86/xen/Kconfig |    2 +-
> > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > >>
> > >> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > >> index 93ff4e1..8cada4c 100644
> > >> --- a/arch/x86/xen/Kconfig
> > >> +++ b/arch/x86/xen/Kconfig
> > >> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> > >>
> > >>  config XEN_X86_PVH
> > >>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > >
> > > Why not remove this 'EXPERIMENTAL' too ?
> > 
> > It was unclear to me if the feature was actually considered unstable.
> > I can resend with the text removed from the title too, if that's the
> > correct action here?
> 
> It certainly is unstable right now (which is why it was unstaged from
> the v3.9 train). I hope that by v3.10 it won't be - at which
> point this patch (and the EXPERIMENTAL) makes sense.
> 
> So could you respin it please with the text removed as well - and I will
> queue it up in the branch that carries the PVH feature?

We also have the same flag on Xen ARM, and the reason is that the ABI is
not stable yet. As soon as it is (I think soon now), I'll send a patch
to remove EXPERIMENTAL from there too.

Re: [Xen-devel] [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Ian Campbell]

On Sat, 2013-02-23 at 20:47 +0000, Stefano Stabellini wrote:
> On Sat, 23 Feb 2013, Konrad Rzeszutek Wilk wrote:
> > On Sat, Feb 23, 2013 at 09:03:20AM -0800, Kees Cook wrote:
> > > On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> > > <dongsheng.song@gmail.com> wrote:
> > > > On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> > > >>
> > > >> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> > > >> while now and is almost always enabled by default. As agreed during the
> > > >> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> > > >>
> > > >> Signed-off-by: Kees Cook <keescook@chromium.org>
> > > >> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > >> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> > > >> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > > >> ---
> > > >>  arch/x86/xen/Kconfig |    2 +-
> > > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >>
> > > >> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > > >> index 93ff4e1..8cada4c 100644
> > > >> --- a/arch/x86/xen/Kconfig
> > > >> +++ b/arch/x86/xen/Kconfig
> > > >> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> > > >>
> > > >>  config XEN_X86_PVH
> > > >>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > > >
> > > > Why not remove this 'EXPERIMENTAL' too ?
> > > 
> > > It was unclear to me if the feature was actually considered unstable.
> > > I can resend with the text removed from the title too, if that's the
> > > correct action here?
> > 
> > It certainly is unstable right now (which is why it was unstaged from
> > the v3.9 train). I hope that by v3.10 it won't be - at which
> > point this patch (and the EXPERIMENTAL) makes sense.
> > 
> > So could you respin it please with the text removed as well - and I will
> > queue it up in the branch that carries the PVH feature?
> 
> We also have the same flag on Xen ARM, and the reason is that the ABI is
> not stable yet. As soon as it is (I think soon now), I'll send a patch
> to remove EXPERIMENTAL from there too.

In the meantime if the depends EXPERIMENTAL is going away perhaps we
should explain the EXPERIMENTAL in the title:

8<----------------------------------------------------

From bc22bd0f7b20296c449a05d82be950922042bc92 Mon Sep 17 00:00:00 2001
From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 4 Oct 2012 09:12:51 +0100
Subject: [PATCH] arm: xen: explain the EXPERIMENTAL dependency in the Kconfig help

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
---
 arch/arm/Kconfig |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 67874b8..ef14873 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1865,6 +1865,14 @@ config XEN
 	help
 	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
 
+
+	  This option is EXPERIMENTAL because the hypervisor
+	  interfaces which it uses are not yet considered stable
+	  therefore backwards and forwards compatibility is not yet
+	  guaranteed.
+
+	  If unsure, say N.
+
 endmenu
 
 menu "Boot options"
-- 
1.7.2.5

Re: [Xen-devel] [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Stefano Stabellini]

On Mon, 25 Feb 2013, Ian Campbell wrote:
> On Sat, 2013-02-23 at 20:47 +0000, Stefano Stabellini wrote:
> > On Sat, 23 Feb 2013, Konrad Rzeszutek Wilk wrote:
> > > On Sat, Feb 23, 2013 at 09:03:20AM -0800, Kees Cook wrote:
> > > > On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> > > > <dongsheng.song@gmail.com> wrote:
> > > > > On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> > > > >>
> > > > >> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> > > > >> while now and is almost always enabled by default. As agreed during the
> > > > >> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> > > > >>
> > > > >> Signed-off-by: Kees Cook <keescook@chromium.org>
> > > > >> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > > >> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> > > > >> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > > > >> ---
> > > > >>  arch/x86/xen/Kconfig |    2 +-
> > > > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >>
> > > > >> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > > > >> index 93ff4e1..8cada4c 100644
> > > > >> --- a/arch/x86/xen/Kconfig
> > > > >> +++ b/arch/x86/xen/Kconfig
> > > > >> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> > > > >>
> > > > >>  config XEN_X86_PVH
> > > > >>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > > > >
> > > > > Why not remove this 'EXPERIMENTAL' too ?
> > > > 
> > > > It was unclear to me if the feature was actually considered unstable.
> > > > I can resend with the text removed from the title too, if that's the
> > > > correct action here?
> > > 
> > > It certainly is unstable right now (which is why it was unstaged from
> > > the v3.9 train). I hope that by v3.10 it won't be - at which
> > > point this patch (and the EXPERIMENTAL) makes sense.
> > > 
> > > So could you respin it please with the text removed as well - and I will
> > > queue it up in the branch that carries the PVH feature?
> > 
> > We also have the same flag on Xen ARM, and the reason is that the ABI is
> > not stable yet. As soon as it is (I think soon now), I'll send a patch
> > to remove EXPERIMENTAL from there too.
> 
> In the meantime if the depends EXPERIMENTAL is going away perhaps we
> should explain the EXPERIMENTAL in the title:
> 
> 8<----------------------------------------------------
> 
> From bc22bd0f7b20296c449a05d82be950922042bc92 Mon Sep 17 00:00:00 2001
> From: Ian Campbell <ian.campbell@citrix.com>
> Date: Thu, 4 Oct 2012 09:12:51 +0100
> Subject: [PATCH] arm: xen: explain the EXPERIMENTAL dependency in the Kconfig help
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: linux-arm-kernel@lists.infradead.org

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


>  arch/arm/Kconfig |    8 ++++++++
>  1 files changed, 8 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 67874b8..ef14873 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1865,6 +1865,14 @@ config XEN
>  	help
>  	  Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
>  
> +
> +	  This option is EXPERIMENTAL because the hypervisor
> +	  interfaces which it uses are not yet considered stable
> +	  therefore backwards and forwards compatibility is not yet
> +	  guaranteed.
> +
> +	  If unsure, say N.
> +
>  endmenu
>  
>  menu "Boot options"
> -- 
> 1.7.2.5
> 
> 
> 
> 

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Dongsheng Song]

On Sun, Feb 24, 2013 at 1:03 AM, Kees Cook <keescook@chromium.org> wrote:
> On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> <dongsheng.song@gmail.com> wrote:
>> On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
>>>
>>> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
>>> while now and is almost always enabled by default. As agreed during the
>>> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
>>>
>>> Signed-off-by: Kees Cook <keescook@chromium.org>
>>> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>>> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
>>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>> ---
>>>  arch/x86/xen/Kconfig |    2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
>>> index 93ff4e1..8cada4c 100644
>>> --- a/arch/x86/xen/Kconfig
>>> +++ b/arch/x86/xen/Kconfig
>>> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
>>>
>>>  config XEN_X86_PVH
>>>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
>>
>> Why not remove this 'EXPERIMENTAL' too ?
>
> It was unclear to me if the feature was actually considered unstable.
> I can resend with the text removed from the title too, if that's the
> correct action here?
>
> -Kees
>

If such a feature was considered unstable, it should depends on EXPERIMENTAL.
We should not surprised users.

>>
>>> -       depends on X86_64 && XEN && EXPERIMENTAL
>>> +       depends on X86_64 && XEN
>>>         default n
>>>         help
>>>            This option enables support for running as a PVH guest (PV guest
>>> --
>>> 1.7.9.5
>>>
>>>
>>> --
>>> Kees Cook
>>> Chrome OS Security
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>> Please read the FAQ at  http://www.tux.org/lkml/
>
>
>
> --
> Kees Cook
> Chrome OS Security

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Greg Kroah-Hartman]

On Sun, Feb 24, 2013 at 05:51:44PM +0800, Dongsheng Song wrote:
> On Sun, Feb 24, 2013 at 1:03 AM, Kees Cook <keescook@chromium.org> wrote:
> > On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> > <dongsheng.song@gmail.com> wrote:
> >> On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> >>>
> >>> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> >>> while now and is almost always enabled by default. As agreed during the
> >>> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> >>>
> >>> Signed-off-by: Kees Cook <keescook@chromium.org>
> >>> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> >>> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> >>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> >>> ---
> >>>  arch/x86/xen/Kconfig |    2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> >>> index 93ff4e1..8cada4c 100644
> >>> --- a/arch/x86/xen/Kconfig
> >>> +++ b/arch/x86/xen/Kconfig
> >>> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> >>>
> >>>  config XEN_X86_PVH
> >>>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> >>
> >> Why not remove this 'EXPERIMENTAL' too ?
> >
> > It was unclear to me if the feature was actually considered unstable.
> > I can resend with the text removed from the title too, if that's the
> > correct action here?
> >
> > -Kees
> >
> 
> If such a feature was considered unstable, it should depends on EXPERIMENTAL.

CONFIG_EXPERIMENTAL is going away.

> We should not surprised users.

You should not have unstable options in the kernel in the first place,
sorry.

greg k-h

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Stefano Stabellini]

On Sun, 24 Feb 2013, Greg Kroah-Hartman wrote:
> On Sun, Feb 24, 2013 at 05:51:44PM +0800, Dongsheng Song wrote:
> > On Sun, Feb 24, 2013 at 1:03 AM, Kees Cook <keescook@chromium.org> wrote:
> > > On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> > > <dongsheng.song@gmail.com> wrote:
> > >> On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> > >>>
> > >>> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> > >>> while now and is almost always enabled by default. As agreed during the
> > >>> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> > >>>
> > >>> Signed-off-by: Kees Cook <keescook@chromium.org>
> > >>> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > >>> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> > >>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > >>> ---
> > >>>  arch/x86/xen/Kconfig |    2 +-
> > >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> > >>>
> > >>> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > >>> index 93ff4e1..8cada4c 100644
> > >>> --- a/arch/x86/xen/Kconfig
> > >>> +++ b/arch/x86/xen/Kconfig
> > >>> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> > >>>
> > >>>  config XEN_X86_PVH
> > >>>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > >>
> > >> Why not remove this 'EXPERIMENTAL' too ?
> > >
> > > It was unclear to me if the feature was actually considered unstable.
> > > I can resend with the text removed from the title too, if that's the
> > > correct action here?
> > >
> > > -Kees
> > >
> > 
> > If such a feature was considered unstable, it should depends on EXPERIMENTAL.
> 
> CONFIG_EXPERIMENTAL is going away.
> 
> > We should not surprised users.
> 
> You should not have unstable options in the kernel in the first place,
> sorry.
 
With the premise that the removal of CONFIG_EXPERIMENTAL is not an issue
for me personally or my work, I am going to give you my 2 cents on the
matter, but feel free to ignore them :)

While I understand that CONFIG_EXPERIMENTAL has been abused, I feel that
rejecting everything that is not fully stable and with external
interfaces set in stones, might hinder the development of new features.

After all, given how fast the kernel is moving nowadays, maintaining a
project out-of-tree until is completely ready for production can be
very expensive. Merging the project earlier and completing the
development upstream can bring better results. But in these cases one
wouldn't want to "market" the feature as stable yet, because it just
isn't. If CONFIG_EXPERIMENTAL is going away, is there anything in the
kernel that can be used to tag a feature as "I wouldn't use it in
production if I were you"? Maybe just a comment in the kconfig
description?

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Konrad Rzeszutek Wilk]

On Mon, Feb 25, 2013 at 12:39:27PM +0000, Stefano Stabellini wrote:
> On Sun, 24 Feb 2013, Greg Kroah-Hartman wrote:
> > On Sun, Feb 24, 2013 at 05:51:44PM +0800, Dongsheng Song wrote:
> > > On Sun, Feb 24, 2013 at 1:03 AM, Kees Cook <keescook@chromium.org> wrote:
> > > > On Sat, Feb 23, 2013 at 3:59 AM, Dongsheng Song
> > > > <dongsheng.song@gmail.com> wrote:
> > > >> On Sat, Feb 23, 2013 at 3:29 PM, Kees Cook <keescook@chromium.org> wrote:
> > > >>>
> > > >>> The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
> > > >>> while now and is almost always enabled by default. As agreed during the
> > > >>> Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
> > > >>>
> > > >>> Signed-off-by: Kees Cook <keescook@chromium.org>
> > > >>> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > > >>> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> > > >>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > > >>> ---
> > > >>>  arch/x86/xen/Kconfig |    2 +-
> > > >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >>>
> > > >>> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > > >>> index 93ff4e1..8cada4c 100644
> > > >>> --- a/arch/x86/xen/Kconfig
> > > >>> +++ b/arch/x86/xen/Kconfig
> > > >>> @@ -53,7 +53,7 @@ config XEN_DEBUG_FS
> > > >>>
> > > >>>  config XEN_X86_PVH
> > > >>>         bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > > >>
> > > >> Why not remove this 'EXPERIMENTAL' too ?
> > > >
> > > > It was unclear to me if the feature was actually considered unstable.
> > > > I can resend with the text removed from the title too, if that's the
> > > > correct action here?
> > > >
> > > > -Kees
> > > >
> > > 
> > > If such a feature was considered unstable, it should depends on EXPERIMENTAL.
> > 
> > CONFIG_EXPERIMENTAL is going away.
> > 
> > > We should not surprised users.
> > 
> > You should not have unstable options in the kernel in the first place,
> > sorry.

Just to clarify - this 'unstable' part is that the hypercall interface has
not been nailed down. As such the patchseries ('PVH') is not going in
Linus's tree until that is nailed down. However, the 'PVH' is going in
in 3.10 merge window (barring again delays).

Initially it was scheduled to be in v3.8, hence the reason it has
been lingering in #linux-next.

>  
> With the premise that the removal of CONFIG_EXPERIMENTAL is not an issue
> for me personally or my work, I am going to give you my 2 cents on the
> matter, but feel free to ignore them :)
> 
> While I understand that CONFIG_EXPERIMENTAL has been abused, I feel that
> rejecting everything that is not fully stable and with external
> interfaces set in stones, might hinder the development of new features.
> 
> After all, given how fast the kernel is moving nowadays, maintaining a
> project out-of-tree until is completely ready for production can be
> very expensive. Merging the project earlier and completing the
> development upstream can bring better results. But in these cases one
> wouldn't want to "market" the feature as stable yet, because it just
> isn't. If CONFIG_EXPERIMENTAL is going away, is there anything in the
> kernel that can be used to tag a feature as "I wouldn't use it in
> production if I were you"? Maybe just a comment in the kconfig
> description?

Re: [PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Greg Kroah-Hartman]

On Mon, Feb 25, 2013 at 12:39:27PM +0000, Stefano Stabellini wrote:
> On Sun, 24 Feb 2013, Greg Kroah-Hartman wrote:
> > 
> > You should not have unstable options in the kernel in the first place,
> > sorry.
>  
> With the premise that the removal of CONFIG_EXPERIMENTAL is not an issue
> for me personally or my work, I am going to give you my 2 cents on the
> matter, but feel free to ignore them :)
> 
> While I understand that CONFIG_EXPERIMENTAL has been abused, I feel that
> rejecting everything that is not fully stable and with external
> interfaces set in stones, might hinder the development of new features.

It's been this way for _years_ this isn't something new (the "you have
to get it right really quickly" problem).  See Documentation/ABI/ for
some words about how you can try to do this.

> After all, given how fast the kernel is moving nowadays,

No faster than it has in the past.

> maintaining a project out-of-tree until is completely ready for
> production can be very expensive. Merging the project earlier and
> completing the development upstream can bring better results.

Yes, but don't go changing user-visable apis when you do so.  That's
been a hard rule for a LONG time.

> But in these cases one wouldn't want to "market" the feature as stable
> yet, because it just isn't. If CONFIG_EXPERIMENTAL is going away, is
> there anything in the kernel that can be used to tag a feature as "I
> wouldn't use it in production if I were you"? Maybe just a comment in
> the kconfig description?

I know this is hard, I've had my own problems with it in the past.  You
don't know if you get an api right until you have a lot of users.  See
our previous "discussions" about this topic on lkml if you are curious
as to the eventual outcome of threads like this:

	Yes, it's hard, but that's kernel programming.

Sorry,

greg k-h

[PATCH] arch/x86/xen: remove depends on CONFIG_EXPERIMENTAL

[Kees Cook]

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/xen/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 93ff4e1..8cada4c 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -53,7 +53,7 @@ config XEN_DEBUG_FS
 
 config XEN_X86_PVH
 	bool "Support for running as a PVH guest (EXPERIMENTAL)"
-	depends on X86_64 && XEN && EXPERIMENTAL
+	depends on X86_64 && XEN
 	default n
 	help
 	   This option enables support for running as a PVH guest (PV guest
-- 
1.7.9.5


-- 
Kees Cook
Chrome OS Security