[PATCH 0/4] xen kconfig tweaks

[PATCH 0/4] xen kconfig tweaks

[Andrew Jones]

This series is a collection of xen kconfig fixes and additions.

Andrew Jones (4):
  xen kconfig: keep XEN_XENBUS_FRONTEND builtin
  xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps
  xen kconfig: add dom0 support help text
  xen kconfig: describe xen tmem in the config menu

 arch/x86/xen/Kconfig       |    7 ++++++-
 drivers/input/misc/Kconfig |    2 +-
 drivers/video/Kconfig      |    1 +
 drivers/xen/Kconfig        |    4 ++--
 4 files changed, 10 insertions(+), 4 deletions(-)

-- 
1.7.7.5

[PATCH 1/4] xen kconfig: keep XEN_XENBUS_FRONTEND builtin

[Andrew Jones]

When XEN_XENBUS_FRONTEND gets selected as a module it can lead to
unbootable configs. If we need it, then we should just build it in.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 drivers/xen/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 8795480..1d24061 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -118,7 +118,7 @@ config XEN_SYS_HYPERVISOR
 	 but will have no xen contents.
 
 config XEN_XENBUS_FRONTEND
-	tristate
+	bool
 
 config XEN_GNTDEV
 	tristate "userspace grant access device driver"
-- 
1.7.7.5

[PATCH 2/4] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Andrew Jones]

PV-on-HVM guests may want to use the xen keyboard/mouse frontend, but
they don't use the xen frame buffer frontend. For this case it doesn't
make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
XEN_FBDEV_FRONTEND. The opposite direction always makes more sense, i.e.
if you're using xenfb, then you'll want xenkbd. Switch the dependencies.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 drivers/input/misc/Kconfig |    2 +-
 drivers/video/Kconfig      |    1 +
 2 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 22d875f..36c15bf 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
 
 config INPUT_XEN_KBDDEV_FRONTEND
 	tristate "Xen virtual keyboard and mouse support"
-	depends on XEN_FBDEV_FRONTEND
+	depends on XEN
 	default y
 	select XEN_XENBUS_FRONTEND
 	help
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index d83e967..269b299 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2269,6 +2269,7 @@ config XEN_FBDEV_FRONTEND
 	select FB_SYS_IMAGEBLIT
 	select FB_SYS_FOPS
 	select FB_DEFERRED_IO
+	select INPUT_XEN_KBDDEV_FRONTEND
 	select XEN_XENBUS_FRONTEND
 	default y
 	help
-- 
1.7.7.5

Re: [Xen-devel] [PATCH 2/4] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Konrad Rzeszutek Wilk]

On Fri, Jan 06, 2012 at 10:43:09AM +0100, Andrew Jones wrote:
> PV-on-HVM guests may want to use the xen keyboard/mouse frontend, but
> they don't use the xen frame buffer frontend. For this case it doesn't
> make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> XEN_FBDEV_FRONTEND. The opposite direction always makes more sense, i.e.
> if you're using xenfb, then you'll want xenkbd. Switch the dependencies.

You need to CC as well these people that have 'maintainer' field on them:

konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
drivers/video/Kconfig
Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
(maintainer:FRAMEBUFFER LAYER)
linux-fbdev@vger.kernel.org (open list:FRAMEBUFFER LAYER)
linux-kernel@vger.kernel.org (open list)
konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
drivers/input/misc/Kconfig
Dmitry Torokhov <dmitry.torokhov@gmail.com> (maintainer:INPUT
(KEYBOARD,...,commit_signer:9/16=56%)
Samuel Ortiz <sameo@linux.intel.com> (commit_signer:3/16=19%)
Anirudh Ghayal <aghayal@codeaurora.org> (commit_signer:2/16=12%)
Peter Ujfalusi <peter.ujfalusi@ti.com> (commit_signer:2/16=12%)
Alan Cox <alan@linux.intel.com> (commit_signer:2/16=12%)
linux-input@vger.kernel.org (open list:INPUT (KEYBOARD,...)
linux-kernel@vger.kernel.org (open list)

> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  drivers/input/misc/Kconfig |    2 +-
>  drivers/video/Kconfig      |    1 +
>  2 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 22d875f..36c15bf 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
>  
>  config INPUT_XEN_KBDDEV_FRONTEND
>  	tristate "Xen virtual keyboard and mouse support"
> -	depends on XEN_FBDEV_FRONTEND
> +	depends on XEN
>  	default y
>  	select XEN_XENBUS_FRONTEND
>  	help
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index d83e967..269b299 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -2269,6 +2269,7 @@ config XEN_FBDEV_FRONTEND
>  	select FB_SYS_IMAGEBLIT
>  	select FB_SYS_FOPS
>  	select FB_DEFERRED_IO
> +	select INPUT_XEN_KBDDEV_FRONTEND
>  	select XEN_XENBUS_FRONTEND
>  	default y
>  	help
> -- 
> 1.7.7.5
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [PATCH 2/4] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Andrew Jones]

----- Original Message -----
> On Fri, Jan 06, 2012 at 10:43:09AM +0100, Andrew Jones wrote:
> > PV-on-HVM guests may want to use the xen keyboard/mouse frontend,
> > but
> > they don't use the xen frame buffer frontend. For this case it
> > doesn't
> > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > XEN_FBDEV_FRONTEND. The opposite direction always makes more sense,
> > i.e.
> > if you're using xenfb, then you'll want xenkbd. Switch the
> > dependencies.
> 
> You need to CC as well these people that have 'maintainer' field on
> them:
> 
> konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
> drivers/video/Kconfig
> Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
> (maintainer:FRAMEBUFFER LAYER)
> linux-fbdev@vger.kernel.org (open list:FRAMEBUFFER LAYER)
> linux-kernel@vger.kernel.org (open list)
> konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
> drivers/input/misc/Kconfig
> Dmitry Torokhov <dmitry.torokhov@gmail.com> (maintainer:INPUT
> (KEYBOARD,...,commit_signer:9/16=56%)
> Samuel Ortiz <sameo@linux.intel.com> (commit_signer:3/16=19%)
> Anirudh Ghayal <aghayal@codeaurora.org> (commit_signer:2/16=12%)
> Peter Ujfalusi <peter.ujfalusi@ti.com> (commit_signer:2/16=12%)
> Alan Cox <alan@linux.intel.com> (commit_signer:2/16=12%)
> linux-input@vger.kernel.org (open list:INPUT (KEYBOARD,...)
> linux-kernel@vger.kernel.org (open list)
> 

Thanks. Replied with them in CC.

Drew

> > 
> > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > ---
> >  drivers/input/misc/Kconfig |    2 +-
> >  drivers/video/Kconfig      |    1 +
> >  2 files changed, 2 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/input/misc/Kconfig
> > b/drivers/input/misc/Kconfig
> > index 22d875f..36c15bf 100644
> > --- a/drivers/input/misc/Kconfig
> > +++ b/drivers/input/misc/Kconfig
> > @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
> >  
> >  config INPUT_XEN_KBDDEV_FRONTEND
> >  	tristate "Xen virtual keyboard and mouse support"
> > -	depends on XEN_FBDEV_FRONTEND
> > +	depends on XEN
> >  	default y
> >  	select XEN_XENBUS_FRONTEND
> >  	help
> > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > index d83e967..269b299 100644
> > --- a/drivers/video/Kconfig
> > +++ b/drivers/video/Kconfig
> > @@ -2269,6 +2269,7 @@ config XEN_FBDEV_FRONTEND
> >  	select FB_SYS_IMAGEBLIT
> >  	select FB_SYS_FOPS
> >  	select FB_DEFERRED_IO
> > +	select INPUT_XEN_KBDDEV_FRONTEND
> >  	select XEN_XENBUS_FRONTEND
> >  	default y
> >  	help
> > --
> > 1.7.7.5
> > 
> > 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel
> 

Re: [PATCH 2/4] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Dmitry Torokhov]

Hi Andrew,

On Fri, Jan 06, 2012 at 10:58:06AM -0500, Andrew Jones wrote:
> 
> 
> ----- Original Message -----
> > On Fri, Jan 06, 2012 at 10:43:09AM +0100, Andrew Jones wrote:
> > > PV-on-HVM guests may want to use the xen keyboard/mouse frontend,
> > > but
> > > they don't use the xen frame buffer frontend. For this case it
> > > doesn't
> > > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > > XEN_FBDEV_FRONTEND. The opposite direction always makes more sense,
> > > i.e.
> > > if you're using xenfb, then you'll want xenkbd. Switch the
> > > dependencies.
> > 
> > You need to CC as well these people that have 'maintainer' field on
> > them:
> > 
> > konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
> > drivers/video/Kconfig
> > Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
> > (maintainer:FRAMEBUFFER LAYER)
> > linux-fbdev@vger.kernel.org (open list:FRAMEBUFFER LAYER)
> > linux-kernel@vger.kernel.org (open list)
> > konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
> > drivers/input/misc/Kconfig
> > Dmitry Torokhov <dmitry.torokhov@gmail.com> (maintainer:INPUT
> > (KEYBOARD,...,commit_signer:9/16=56%)
> > Samuel Ortiz <sameo@linux.intel.com> (commit_signer:3/16=19%)
> > Anirudh Ghayal <aghayal@codeaurora.org> (commit_signer:2/16=12%)
> > Peter Ujfalusi <peter.ujfalusi@ti.com> (commit_signer:2/16=12%)
> > Alan Cox <alan@linux.intel.com> (commit_signer:2/16=12%)
> > linux-input@vger.kernel.org (open list:INPUT (KEYBOARD,...)
> > linux-kernel@vger.kernel.org (open list)
> > 
> 
> Thanks. Replied with them in CC.
> 
> Drew
> 
> > > 
> > > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > > ---
> > >  drivers/input/misc/Kconfig |    2 +-
> > >  drivers/video/Kconfig      |    1 +
> > >  2 files changed, 2 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/drivers/input/misc/Kconfig
> > > b/drivers/input/misc/Kconfig
> > > index 22d875f..36c15bf 100644
> > > --- a/drivers/input/misc/Kconfig
> > > +++ b/drivers/input/misc/Kconfig
> > > @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
> > >  
> > >  config INPUT_XEN_KBDDEV_FRONTEND
> > >  	tristate "Xen virtual keyboard and mouse support"
> > > -	depends on XEN_FBDEV_FRONTEND
> > > +	depends on XEN

This is OK with me.

> > >  	default y
> > >  	select XEN_XENBUS_FRONTEND
> > >  	help
> > > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > > index d83e967..269b299 100644
> > > --- a/drivers/video/Kconfig
> > > +++ b/drivers/video/Kconfig
> > > @@ -2269,6 +2269,7 @@ config XEN_FBDEV_FRONTEND
> > >  	select FB_SYS_IMAGEBLIT
> > >  	select FB_SYS_FOPS
> > >  	select FB_DEFERRED_IO
> > > +	select INPUT_XEN_KBDDEV_FRONTEND

But here you need to either depend on or select INPUT as select does not
resolve dependencies for selected symbol.

Thanks.

-- 
Dmitry

Re: [Xen-devel] [PATCH 2/4] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Andrew Jones]

----- Original Message -----
> Hi Andrew,
> 
> On Fri, Jan 06, 2012 at 10:58:06AM -0500, Andrew Jones wrote:
> > 
> > 
> > ----- Original Message -----
> > > On Fri, Jan 06, 2012 at 10:43:09AM +0100, Andrew Jones wrote:
> > > > PV-on-HVM guests may want to use the xen keyboard/mouse
> > > > frontend,
> > > > but
> > > > they don't use the xen frame buffer frontend. For this case it
> > > > doesn't
> > > > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > > > XEN_FBDEV_FRONTEND. The opposite direction always makes more
> > > > sense,
> > > > i.e.
> > > > if you're using xenfb, then you'll want xenkbd. Switch the
> > > > dependencies.
> > > 
> > > You need to CC as well these people that have 'maintainer' field
> > > on
> > > them:
> > > 
> > > konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
> > > drivers/video/Kconfig
> > > Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
> > > (maintainer:FRAMEBUFFER LAYER)
> > > linux-fbdev@vger.kernel.org (open list:FRAMEBUFFER LAYER)
> > > linux-kernel@vger.kernel.org (open list)
> > > konrad@phenom:~/work/linux$ scripts/get_maintainer.pl -f
> > > drivers/input/misc/Kconfig
> > > Dmitry Torokhov <dmitry.torokhov@gmail.com> (maintainer:INPUT
> > > (KEYBOARD,...,commit_signer:9/16=56%)
> > > Samuel Ortiz <sameo@linux.intel.com> (commit_signer:3/16=19%)
> > > Anirudh Ghayal <aghayal@codeaurora.org> (commit_signer:2/16=12%)
> > > Peter Ujfalusi <peter.ujfalusi@ti.com> (commit_signer:2/16=12%)
> > > Alan Cox <alan@linux.intel.com> (commit_signer:2/16=12%)
> > > linux-input@vger.kernel.org (open list:INPUT (KEYBOARD,...)
> > > linux-kernel@vger.kernel.org (open list)
> > > 
> > 
> > Thanks. Replied with them in CC.
> > 
> > Drew
> > 
> > > > 
> > > > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > > > ---
> > > >  drivers/input/misc/Kconfig |    2 +-
> > > >  drivers/video/Kconfig      |    1 +
> > > >  2 files changed, 2 insertions(+), 1 deletions(-)
> > > > 
> > > > diff --git a/drivers/input/misc/Kconfig
> > > > b/drivers/input/misc/Kconfig
> > > > index 22d875f..36c15bf 100644
> > > > --- a/drivers/input/misc/Kconfig
> > > > +++ b/drivers/input/misc/Kconfig
> > > > @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
> > > >  
> > > >  config INPUT_XEN_KBDDEV_FRONTEND
> > > >  	tristate "Xen virtual keyboard and mouse support"
> > > > -	depends on XEN_FBDEV_FRONTEND
> > > > +	depends on XEN
> 
> This is OK with me.
> 
> > > >  	default y
> > > >  	select XEN_XENBUS_FRONTEND
> > > >  	help
> > > > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > > > index d83e967..269b299 100644
> > > > --- a/drivers/video/Kconfig
> > > > +++ b/drivers/video/Kconfig
> > > > @@ -2269,6 +2269,7 @@ config XEN_FBDEV_FRONTEND
> > > >  	select FB_SYS_IMAGEBLIT
> > > >  	select FB_SYS_FOPS
> > > >  	select FB_DEFERRED_IO
> > > > +	select INPUT_XEN_KBDDEV_FRONTEND
> 
> But here you need to either depend on or select INPUT as select does
> not
> resolve dependencies for selected symbol.
> 

Would I actually need 'select INPUT' and select 'INPUT_MISC'? Maybe
'depends on' would just be cleaner and safer. I'll send a V2.

Thanks,
Drew


> Thanks.
> 
> --
> Dmitry
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 

[PATCH 2/4 v2] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Andrew Jones]

PV-on-HVM guests may want to use the xen keyboard/mouse frontend, but
they don't use the xen frame buffer frontend. For this case it doesn't
make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
XEN_FBDEV_FRONTEND. The opposite direction always makes more sense, i.e.
if you're using xenfb, then you'll want xenkbd. Switch the dependencies.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 drivers/input/misc/Kconfig |    2 +-
 drivers/video/Kconfig      |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 22d875f..36c15bf 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
 
 config INPUT_XEN_KBDDEV_FRONTEND
 	tristate "Xen virtual keyboard and mouse support"
-	depends on XEN_FBDEV_FRONTEND
+	depends on XEN
 	default y
 	select XEN_XENBUS_FRONTEND
 	help
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index d83e967..3e38c2f 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -2263,7 +2263,7 @@ config FB_VIRTUAL
 
 config XEN_FBDEV_FRONTEND
 	tristate "Xen virtual frame buffer support"
-	depends on FB && XEN
+	depends on FB && XEN && INPUT_XEN_KBDDEV_FRONTEND
 	select FB_SYS_FILLRECT
 	select FB_SYS_COPYAREA
 	select FB_SYS_IMAGEBLIT
-- 
1.7.7.5

Re: [Xen-devel] [PATCH 2/4 v2] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Konrad Rzeszutek Wilk]

On Mon, Jan 09, 2012 at 06:51:41PM +0100, Andrew Jones wrote:
> PV-on-HVM guests may want to use the xen keyboard/mouse frontend, but
> they don't use the xen frame buffer frontend. For this case it doesn't

Ok, but PV does?
> make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> XEN_FBDEV_FRONTEND. The opposite direction always makes more sense, i.e.
> if you're using xenfb, then you'll want xenkbd. Switch the dependencies.

That sounds like it would be universal irregardless if it is
PV or PVonHVM?
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  drivers/input/misc/Kconfig |    2 +-
>  drivers/video/Kconfig      |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 22d875f..36c15bf 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
>  
>  config INPUT_XEN_KBDDEV_FRONTEND
>  	tristate "Xen virtual keyboard and mouse support"
> -	depends on XEN_FBDEV_FRONTEND
> +	depends on XEN
>  	default y
>  	select XEN_XENBUS_FRONTEND
>  	help
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index d83e967..3e38c2f 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -2263,7 +2263,7 @@ config FB_VIRTUAL
>  
>  config XEN_FBDEV_FRONTEND
>  	tristate "Xen virtual frame buffer support"
> -	depends on FB && XEN
> +	depends on FB && XEN && INPUT_XEN_KBDDEV_FRONTEND
>  	select FB_SYS_FILLRECT
>  	select FB_SYS_COPYAREA
>  	select FB_SYS_IMAGEBLIT
> -- 
> 1.7.7.5
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [Xen-devel] [PATCH 2/4 v2] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Andrew Jones]

----- Original Message -----
> On Mon, Jan 09, 2012 at 06:51:41PM +0100, Andrew Jones wrote:
> > PV-on-HVM guests may want to use the xen keyboard/mouse frontend,
> > but
> > they don't use the xen frame buffer frontend. For this case it
> > doesn't
> 
> Ok, but PV does?
> > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > XEN_FBDEV_FRONTEND. The opposite direction always makes more sense,
> > i.e.
> > if you're using xenfb, then you'll want xenkbd. Switch the
> > dependencies.
> 
> That sounds like it would be universal irregardless if it is
> PV or PVonHVM?

This patch makes it such that if you want to use both, then you must
select both. It also says that if you want FB, then you need the
KBD. However, if you only want the KBD then you're fine with just
that. So there isn't any risk of breaking configs designed to use
FB, because FB should be manually selected for those configs anyway.

Drew

> > 
> > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > ---
> >  drivers/input/misc/Kconfig |    2 +-
> >  drivers/video/Kconfig      |    2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/input/misc/Kconfig
> > b/drivers/input/misc/Kconfig
> > index 22d875f..36c15bf 100644
> > --- a/drivers/input/misc/Kconfig
> > +++ b/drivers/input/misc/Kconfig
> > @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
> >  
> >  config INPUT_XEN_KBDDEV_FRONTEND
> >  	tristate "Xen virtual keyboard and mouse support"
> > -	depends on XEN_FBDEV_FRONTEND
> > +	depends on XEN
> >  	default y
> >  	select XEN_XENBUS_FRONTEND
> >  	help
> > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > index d83e967..3e38c2f 100644
> > --- a/drivers/video/Kconfig
> > +++ b/drivers/video/Kconfig
> > @@ -2263,7 +2263,7 @@ config FB_VIRTUAL
> >  
> >  config XEN_FBDEV_FRONTEND
> >  	tristate "Xen virtual frame buffer support"
> > -	depends on FB && XEN
> > +	depends on FB && XEN && INPUT_XEN_KBDDEV_FRONTEND
> >  	select FB_SYS_FILLRECT
> >  	select FB_SYS_COPYAREA
> >  	select FB_SYS_IMAGEBLIT
> > --
> > 1.7.7.5
> > 
> > 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel
> 

Re: [Xen-devel] [PATCH 2/4 v2] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Konrad Rzeszutek Wilk]

On Wed, Jan 11, 2012 at 11:29:20AM -0500, Andrew Jones wrote:
> 
> 
> ----- Original Message -----
> > On Mon, Jan 09, 2012 at 06:51:41PM +0100, Andrew Jones wrote:
> > > PV-on-HVM guests may want to use the xen keyboard/mouse frontend,
> > > but
> > > they don't use the xen frame buffer frontend. For this case it
> > > doesn't
> > 
> > Ok, but PV does?
> > > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > > XEN_FBDEV_FRONTEND. The opposite direction always makes more sense,
> > > i.e.
> > > if you're using xenfb, then you'll want xenkbd. Switch the
> > > dependencies.
> > 
> > That sounds like it would be universal irregardless if it is
> > PV or PVonHVM?
> 
> This patch makes it such that if you want to use both, then you must
> select both. It also says that if you want FB, then you need the
> KBD. However, if you only want the KBD then you're fine with just
> that. So there isn't any risk of breaking configs designed to use
> FB, because FB should be manually selected for those configs anyway.

Dmitry,

I am OK with this patch. Should I pick it up on my tree for 3.4 or
are you OK doing it via your tree?

Thanks!
> 
> Drew
> 
> > > 
> > > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > > ---
> > >  drivers/input/misc/Kconfig |    2 +-
> > >  drivers/video/Kconfig      |    2 +-
> > >  2 files changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/input/misc/Kconfig
> > > b/drivers/input/misc/Kconfig
> > > index 22d875f..36c15bf 100644
> > > --- a/drivers/input/misc/Kconfig
> > > +++ b/drivers/input/misc/Kconfig
> > > @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
> > >  
> > >  config INPUT_XEN_KBDDEV_FRONTEND
> > >  	tristate "Xen virtual keyboard and mouse support"
> > > -	depends on XEN_FBDEV_FRONTEND
> > > +	depends on XEN
> > >  	default y
> > >  	select XEN_XENBUS_FRONTEND
> > >  	help
> > > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > > index d83e967..3e38c2f 100644
> > > --- a/drivers/video/Kconfig
> > > +++ b/drivers/video/Kconfig
> > > @@ -2263,7 +2263,7 @@ config FB_VIRTUAL
> > >  
> > >  config XEN_FBDEV_FRONTEND
> > >  	tristate "Xen virtual frame buffer support"
> > > -	depends on FB && XEN
> > > +	depends on FB && XEN && INPUT_XEN_KBDDEV_FRONTEND
> > >  	select FB_SYS_FILLRECT
> > >  	select FB_SYS_COPYAREA
> > >  	select FB_SYS_IMAGEBLIT
> > > --
> > > 1.7.7.5
> > > 
> > > 
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@lists.xensource.com
> > > http://lists.xensource.com/xen-devel
> > 

Re: [Xen-devel] [PATCH 2/4 v2] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Dmitry Torokhov]

On Thu, Mar 15, 2012 at 01:23:05PM -0400, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 11, 2012 at 11:29:20AM -0500, Andrew Jones wrote:
> > 
> > 
> > ----- Original Message -----
> > > On Mon, Jan 09, 2012 at 06:51:41PM +0100, Andrew Jones wrote:
> > > > PV-on-HVM guests may want to use the xen keyboard/mouse frontend,
> > > > but
> > > > they don't use the xen frame buffer frontend. For this case it
> > > > doesn't
> > > 
> > > Ok, but PV does?
> > > > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > > > XEN_FBDEV_FRONTEND. The opposite direction always makes more sense,
> > > > i.e.
> > > > if you're using xenfb, then you'll want xenkbd. Switch the
> > > > dependencies.
> > > 
> > > That sounds like it would be universal irregardless if it is
> > > PV or PVonHVM?
> > 
> > This patch makes it such that if you want to use both, then you must
> > select both. It also says that if you want FB, then you need the
> > KBD. However, if you only want the KBD then you're fine with just
> > that. So there isn't any risk of breaking configs designed to use
> > FB, because FB should be manually selected for those configs anyway.
> 
> Dmitry,
> 
> I am OK with this patch. Should I pick it up on my tree for 3.4 or
> are you OK doing it via your tree?

Konrad,

I don't have a good copy of the patch so it you could pick it up that
would be great.

Thanks.

-- 
Dmitry

Re: [Xen-devel] [PATCH 2/4 v2] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Konrad Rzeszutek Wilk]

On Thu, Mar 15, 2012 at 11:24:28PM -0700, Dmitry Torokhov wrote:
> On Thu, Mar 15, 2012 at 01:23:05PM -0400, Konrad Rzeszutek Wilk wrote:
> > On Wed, Jan 11, 2012 at 11:29:20AM -0500, Andrew Jones wrote:
> > > 
> > > 
> > > ----- Original Message -----
> > > > On Mon, Jan 09, 2012 at 06:51:41PM +0100, Andrew Jones wrote:
> > > > > PV-on-HVM guests may want to use the xen keyboard/mouse frontend,
> > > > > but
> > > > > they don't use the xen frame buffer frontend. For this case it
> > > > > doesn't
> > > > 
> > > > Ok, but PV does?
> > > > > make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> > > > > XEN_FBDEV_FRONTEND. The opposite direction always makes more sense,
> > > > > i.e.
> > > > > if you're using xenfb, then you'll want xenkbd. Switch the
> > > > > dependencies.
> > > > 
> > > > That sounds like it would be universal irregardless if it is
> > > > PV or PVonHVM?
> > > 
> > > This patch makes it such that if you want to use both, then you must
> > > select both. It also says that if you want FB, then you need the
> > > KBD. However, if you only want the KBD then you're fine with just
> > > that. So there isn't any risk of breaking configs designed to use
> > > FB, because FB should be manually selected for those configs anyway.
> > 
> > Dmitry,
> > 
> > I am OK with this patch. Should I pick it up on my tree for 3.4 or
> > are you OK doing it via your tree?
> 
> Konrad,
> 
> I don't have a good copy of the patch so it you could pick it up that
> would be great.

OK, will stick you Ack on it. Thx!
> 
> Thanks.
> 
> -- 
> Dmitry
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Re: [PATCH 2/4] xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps

[Konrad Rzeszutek Wilk]

On Fri, Jan 06, 2012 at 10:43:09AM +0100, Andrew Jones wrote:
> PV-on-HVM guests may want to use the xen keyboard/mouse frontend, but
> they don't use the xen frame buffer frontend. For this case it doesn't
> make much sense for INPUT_XEN_KBDDEV_FRONTEND to depend on
> XEN_FBDEV_FRONTEND. The opposite direction always makes more sense, i.e.
> if you're using xenfb, then you'll want xenkbd. Switch the dependencies.

This looks OK. Let me test this out to see if there is any silly
fallout.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  drivers/input/misc/Kconfig |    2 +-
>  drivers/video/Kconfig      |    1 +
>  2 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 22d875f..36c15bf 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -533,7 +533,7 @@ config INPUT_CMA3000_I2C
>  
>  config INPUT_XEN_KBDDEV_FRONTEND
>  	tristate "Xen virtual keyboard and mouse support"
> -	depends on XEN_FBDEV_FRONTEND
> +	depends on XEN
>  	default y
>  	select XEN_XENBUS_FRONTEND
>  	help
> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> index d83e967..269b299 100644
> --- a/drivers/video/Kconfig
> +++ b/drivers/video/Kconfig
> @@ -2269,6 +2269,7 @@ config XEN_FBDEV_FRONTEND
>  	select FB_SYS_IMAGEBLIT
>  	select FB_SYS_FOPS
>  	select FB_DEFERRED_IO
> +	select INPUT_XEN_KBDDEV_FRONTEND
>  	select XEN_XENBUS_FRONTEND
>  	default y
>  	help
> -- 
> 1.7.7.5

[PATCH 3/4] xen kconfig: add dom0 support help text

[Andrew Jones]

Describe dom0 support in the config menu and supply help text for it.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 arch/x86/xen/Kconfig |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 26c731a..88862d5 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -14,9 +14,14 @@ config XEN
 	  Xen hypervisor.
 
 config XEN_DOM0
-	def_bool y
+	bool "Xen Initial Domain (Dom0) support"
+	default y
 	depends on XEN && PCI_XEN && SWIOTLB_XEN
 	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
+	help
+	  This allows the kernel to be used for the initial Xen domain,
+	  Domain0. This is a privileged guest that supplies backends
+	  and is used to manage the other Xen domains.
 
 # Dummy symbol since people have come to rely on the PRIVILEGED_GUEST
 # name in tools.
-- 
1.7.7.5

[PATCH 3/4 v2] xen kconfig: add dom0 support help text

[Andrew Jones]

Describe dom0 support in the config menu and supply help text for it.

v2 adds 'if EXPERT' to keep it out of the "standard" menu.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 arch/x86/xen/Kconfig |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 26c731a..31ec975 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -14,9 +14,14 @@ config XEN
 	  Xen hypervisor.
 
 config XEN_DOM0
-	def_bool y
+	bool "Xen Initial Domain (Dom0) support" if EXPERT
+	default y
 	depends on XEN && PCI_XEN && SWIOTLB_XEN
 	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
+	help
+	  This allows the kernel to be used for the initial Xen domain,
+	  Domain0. This is a privileged guest that supplies backends
+	  and is used to manage the other Xen domains.
 
 # Dummy symbol since people have come to rely on the PRIVILEGED_GUEST
 # name in tools.
-- 
1.7.7.5

Re: [Xen-devel] [PATCH 3/4 v2] xen kconfig: add dom0 support help text

[Andrew Jones]

----- Original Message -----
> Describe dom0 support in the config menu and supply help text for it.
> 
> v2 adds 'if EXPERT' to keep it out of the "standard" menu.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  arch/x86/xen/Kconfig |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index 26c731a..31ec975 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -14,9 +14,14 @@ config XEN
>  	  Xen hypervisor.
>  
>  config XEN_DOM0
> -	def_bool y
> +	bool "Xen Initial Domain (Dom0) support" if EXPERT
> +	default y
>  	depends on XEN && PCI_XEN && SWIOTLB_XEN
>  	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
> +	help
> +	  This allows the kernel to be used for the initial Xen domain,
> +	  Domain0. This is a privileged guest that supplies backends
> +	  and is used to manage the other Xen domains.
>  
>  # Dummy symbol since people have come to rely on the
>  PRIVILEGED_GUEST
>  # name in tools.
> --
> 1.7.7.5

There's currently an issue using EXPERT. It doesn't make this
patch wrong, but any users that would want to turn EXPERT on, in
order to turn DOM0 off, would find that their configs have gotten
twisted in other ways as well. I've posted a patch for EXPERT, and
if it gets merged, then I really can't see any good arguments against
this patch.

Drew

Re: [PATCH 3/4] xen kconfig: add dom0 support help text

[Konrad Rzeszutek Wilk]

On Fri, Jan 06, 2012 at 10:43:10AM +0100, Andrew Jones wrote:
> Describe dom0 support in the config menu and supply help text for it.

So I had this reply in my draft and forgot to send it. Sorry about that.

My understanding from the converstion was that we try to "squash"
the XEN_DOM0 option so that it would not be present. But that did not
work as it lead to a string of X86_LOCAL_APIC, X86_IO_ACPI, ACPI, PCI,
and so on. Then the .h with #define XEN_something based on those
symbols, but that is not the job of a header file. It is the job
of Kconfig.

The other way was to squash this in with the backend support. Since
we are moving away from having one initial domain, to having
multitple "initial domains" (priviliged domains) where each can
server as a backend.  However (quoting Jeremy) "it is more of
disaggregating the privilege to reduce the amount concentrated in any one
part.  Backends don't need any more privilege than to be able to
access the specific device(s) they're being the backend for."

Interestingly, that means DOM0 is kind of .. well, it should be
no different from a normal HVM guest. The old-style PV dom0 remains
would be ..well, almost nothing. The Xen MMU, and Xen SWIOTLB - those
are the ones that pop in mind for Dom0, but they are also used
for PV PCI. In fact, all (I think?) of the CONFIG_XEN_DOM0 functionality
can be _used_ in a PV guest. The 'if (initial_xen_domain()' should
probably be addressed first and to figure which one of those can be
altered as the "backend domain" can run both frontend and backend drivers
(oh joy!). So more relaxing those config options and/or "if (xen..)".

Anyhow, back to the HVM dom0 - that is in the future - and it is going
to take a couple of years to get it. I would rather not shoot my
foot by removing these CONFIG_* option until we get a better grasp of how
we want to deal with the PV hybrid.

What I am saying is that I don't know what the right answer is,
but I don't believe the patch below is it. I wish I had a better
answer in terms of "do this instead", but none of those worked.

Perhaps we can brainstorm some of this at XenSummit by which time
I hope Mukesh's PV hybrid work will be completed and a lot of the
work on the toolstack for backend drivers will be laid out.

> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  arch/x86/xen/Kconfig |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index 26c731a..88862d5 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -14,9 +14,14 @@ config XEN
>  	  Xen hypervisor.
>  
>  config XEN_DOM0
> -	def_bool y
> +	bool "Xen Initial Domain (Dom0) support"
> +	default y
>  	depends on XEN && PCI_XEN && SWIOTLB_XEN
>  	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
> +	help
> +	  This allows the kernel to be used for the initial Xen domain,
> +	  Domain0. This is a privileged guest that supplies backends
> +	  and is used to manage the other Xen domains.
>  
>  # Dummy symbol since people have come to rely on the PRIVILEGED_GUEST
>  # name in tools.
> -- 
> 1.7.7.5

[PATCH 4/4] xen kconfig: describe xen tmem in the config menu

[Andrew Jones]

Add a description to the config menu for xen tmem.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 drivers/xen/Kconfig |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 1d24061..7e8d728 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -143,7 +143,7 @@ config SWIOTLB_XEN
 	select SWIOTLB
 
 config XEN_TMEM
-	bool
+	bool "Xen Transcendent Memory (tmem)"
 	default y if (CLEANCACHE || FRONTSWAP)
 	help
 	  Shim to interface in-kernel Transcendent Memory hooks
-- 
1.7.7.5

Re: [PATCH 4/4] xen kconfig: describe xen tmem in the config menu

[Konrad Rzeszutek Wilk]

On Fri, Jan 06, 2012 at 10:43:11AM +0100, Andrew Jones wrote:
> Add a description to the config menu for xen tmem.

I am not sure what this patch gets us. If this is to minimize the
size of the module - so say it gets loaded, but tmem-enabled is 
not set nor cleancache and we just have it consuming memory - we can do it
via returning -ENODEV on the module load.

Like this (completley untested nor compiled tested):

>From 45b49b5d565c52e4396dae036ddb4f4094d914ec Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Mon, 23 Jan 2012 13:32:17 -0500
Subject: [PATCH] xen/tmem: Return -ENODEV if the backends are not registered.

.. otherwise the driver might still reside in the memory consuming
memory (that is the theory at least).

CC: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/tmem.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index d369965..e61b5a3 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -377,8 +377,10 @@ static struct frontswap_ops tmem_frontswap_ops = {
 
 static int __init xen_tmem_init(void)
 {
+	bool loaded = false;
+
 	if (!xen_domain())
-		return 0;
+		return -ENODEV;
 #ifdef CONFIG_FRONTSWAP
 	if (tmem_enabled && use_frontswap) {
 		char *s = "";
@@ -390,6 +392,7 @@ static int __init xen_tmem_init(void)
 			s = " (WARNING: frontswap_ops overridden)";
 		printk(KERN_INFO "frontswap enabled, RAM provided by "
 				 "Xen Transcendent Memory\n");
+		loaded = true;
 	}
 #endif
 #ifdef CONFIG_CLEANCACHE
@@ -402,9 +405,10 @@ static int __init xen_tmem_init(void)
 			s = " (WARNING: cleancache_ops overridden)";
 		printk(KERN_INFO "cleancache enabled, RAM provided by "
 				 "Xen Transcendent Memory%s\n", s);
+		loaded = true;
 	}
 #endif
-	return 0;
+	return loaded ? 0 : -ENODEV;
 }
 
 module_init(xen_tmem_init)
-- 
1.7.7.5


> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  drivers/xen/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 1d24061..7e8d728 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -143,7 +143,7 @@ config SWIOTLB_XEN
>  	select SWIOTLB
>  
>  config XEN_TMEM
> -	bool
> +	bool "Xen Transcendent Memory (tmem)"
>  	default y if (CLEANCACHE || FRONTSWAP)
>  	help
>  	  Shim to interface in-kernel Transcendent Memory hooks
> -- 
> 1.7.7.5

Re: [PATCH 4/4] xen kconfig: describe xen tmem in the config menu

[Igor Mammedov]

On 01/23/2012 07:34 PM, Konrad Rzeszutek Wilk wrote:
> On Fri, Jan 06, 2012 at 10:43:11AM +0100, Andrew Jones wrote:
>> Add a description to the config menu for xen tmem.
>
> I am not sure what this patch gets us. If this is to minimize the
> size of the module - so say it gets loaded, but tmem-enabled is
> not set nor cleancache and we just have it consuming memory - we can do it
> via returning -ENODEV on the module load.

But why compile in something that one may never use? At least with this patch
I'll have a choice to turn it off if I don't need it.
For example when I build hardened kernel, I'd like to turn of all unnecessary
features for a particular config (i.e. reduce attack surface as much as possible).

-- 
Thanks,
  Igor

Re: [Xen-devel] [PATCH 4/4] xen kconfig: describe xen tmem in the config menu

[Konrad Rzeszutek Wilk]

On Tue, Jan 24, 2012 at 09:30:15AM +0100, Igor Mammedov wrote:
> On 01/23/2012 07:34 PM, Konrad Rzeszutek Wilk wrote:
> >On Fri, Jan 06, 2012 at 10:43:11AM +0100, Andrew Jones wrote:
> >>Add a description to the config menu for xen tmem.
> >
> >I am not sure what this patch gets us. If this is to minimize the
> >size of the module - so say it gets loaded, but tmem-enabled is
> >not set nor cleancache and we just have it consuming memory - we can do it
> >via returning -ENODEV on the module load.
> 
> But why compile in something that one may never use? At least with this patch
> I'll have a choice to turn it off if I don't need it.

Then this patch is misleading. It should state at the start
what its purpose is. It sounds like adding the description is just
a way for the real purpose of this patch - which is to disable tmem.

> For example when I build hardened kernel, I'd like to turn of all unnecessary
> features for a particular config (i.e. reduce attack surface as much as possible).

The 'tmem' gets turned off if you disable cleancache. Can't you just
disable cleancache in your hardened config?

Re: [Xen-devel] [PATCH 3/4] xen kconfig: add dom0 support help text

[Stefano Stabellini]

On Fri, 6 Jan 2012, Andrew Jones wrote:
> ----- Original Message -----
> > On Fri, 6 Jan 2012, Andrew Jones wrote:
> > > > Almost all of the things which dom0 needs (e.g. PCI device
> > > > management
> > > > etc) is also required by a domU with passthrough enabled so the
> > > > savings
> > > > are really very slight.
> > > > 
> > > > We are talking less than 1k of code AFAICT, 319 bytes for
> > > > arch/x86/xen/vga.o and 573 for drivers/xen/xenfs/xenstored.o plus
> > > > whatever xen_register_gsi (a couple of dozen lines of code) adds
> > > > to
> > > > arch/x86/pci/xen.o. grep doesn't show CONFIG_XEN_DOM0 being used
> > > > anywhere else. What savings do you see in practice from disabling
> > > > just
> > > > this symbol?
> > > 
> > > I completely agree that the saving are near none. The savings,
> > > however,
> > > aren't the only reason to drive the change. It's actually the
> > > symbol
> > > name itself. Unfortunately configs can be perceived as a contract
> > > of
> > > support, i.e. if feature xyz is enabled in the distro's config,
> > > then
> > > the distributor must have selected, and therefore will support,
> > > said
> > > feature.
> > > 
> > > I didn't make this motivation clear in my initial post, because I
> > > was
> > > hoping to spare people some eye rolling.
> > 
> > I thought that in the kernel community we make decisions based on
> > technical merits rather than "contracts of support".
> 
> Sorry.
> 
> > Given that disabling the symbol saves near to nothing, the logical
> > thing
> > to do is removing the symbol altogether.
> > 
> 
> I thought of that too. If the symbol just goes away, then my
> non-technical requirement will be met and the functionality will
> stay. I consider that a bigger win actually. I didn't suggest it
> though, since I've never done any dom0 development, nor had any
> consideration for dom0 code needs of the future. With
> anti-credentials like that, I'd guess it'd be tougher for me to sell
> the need to remove it, than it is for me to just make it
> configurable.
 
The reason to remove is easy: it is already a silent option and
disabling it saves almost nothing.
I think that removing it should be easy enough but if you don't
feel confident doing it, I can come up with a patch.

Re: [PATCH 3/4] xen kconfig: add dom0 support help text

[Andrew Jones]

----- Original Message -----
> On Fri, 6 Jan 2012, Andrew Jones wrote:
> > ----- Original Message -----
> > > On Fri, 6 Jan 2012, Andrew Jones wrote:
> > > > > Almost all of the things which dom0 needs (e.g. PCI device
> > > > > management
> > > > > etc) is also required by a domU with passthrough enabled so
> > > > > the
> > > > > savings
> > > > > are really very slight.
> > > > > 
> > > > > We are talking less than 1k of code AFAICT, 319 bytes for
> > > > > arch/x86/xen/vga.o and 573 for drivers/xen/xenfs/xenstored.o
> > > > > plus
> > > > > whatever xen_register_gsi (a couple of dozen lines of code)
> > > > > adds
> > > > > to
> > > > > arch/x86/pci/xen.o. grep doesn't show CONFIG_XEN_DOM0 being
> > > > > used
> > > > > anywhere else. What savings do you see in practice from
> > > > > disabling
> > > > > just
> > > > > this symbol?
> > > > 
> > > > I completely agree that the saving are near none. The savings,
> > > > however,
> > > > aren't the only reason to drive the change. It's actually the
> > > > symbol
> > > > name itself. Unfortunately configs can be perceived as a
> > > > contract
> > > > of
> > > > support, i.e. if feature xyz is enabled in the distro's config,
> > > > then
> > > > the distributor must have selected, and therefore will support,
> > > > said
> > > > feature.
> > > > 
> > > > I didn't make this motivation clear in my initial post, because
> > > > I
> > > > was
> > > > hoping to spare people some eye rolling.
> > > 
> > > I thought that in the kernel community we make decisions based on
> > > technical merits rather than "contracts of support".
> > 
> > Sorry.
> > 
> > > Given that disabling the symbol saves near to nothing, the
> > > logical
> > > thing
> > > to do is removing the symbol altogether.
> > > 
> > 
> > I thought of that too. If the symbol just goes away, then my
> > non-technical requirement will be met and the functionality will
> > stay. I consider that a bigger win actually. I didn't suggest it
> > though, since I've never done any dom0 development, nor had any
> > consideration for dom0 code needs of the future. With
> > anti-credentials like that, I'd guess it'd be tougher for me to
> > sell
> > the need to remove it, than it is for me to just make it
> > configurable.
>  
> The reason to remove is easy: it is already a silent option and
> disabling it saves almost nothing.
> I think that removing it should be easy enough but if you don't
> feel confident doing it, I can come up with a patch.
> 

I'll write the patch. It's not the patch I thought would be hard to
do (although I'll only be posting it compile tested, as I don't
have an environment where I can test it set up). What I thought would
be difficult is the justification. However, considering you're
advocating it, I guess I'm good there too.

Drew

Re: [Xen-devel] [PATCH 3/4] xen kconfig: add dom0 support help text

[Stefano Stabellini]

On Fri, 6 Jan 2012, Andrew Jones wrote:
> > Almost all of the things which dom0 needs (e.g. PCI device management
> > etc) is also required by a domU with passthrough enabled so the
> > savings
> > are really very slight.
> > 
> > We are talking less than 1k of code AFAICT, 319 bytes for
> > arch/x86/xen/vga.o and 573 for drivers/xen/xenfs/xenstored.o plus
> > whatever xen_register_gsi (a couple of dozen lines of code) adds to
> > arch/x86/pci/xen.o. grep doesn't show CONFIG_XEN_DOM0 being used
> > anywhere else. What savings do you see in practice from disabling
> > just
> > this symbol?
> 
> I completely agree that the saving are near none. The savings, however,
> aren't the only reason to drive the change. It's actually the symbol
> name itself. Unfortunately configs can be perceived as a contract of
> support, i.e. if feature xyz is enabled in the distro's config, then
> the distributor must have selected, and therefore will support, said
> feature.
> 
> I didn't make this motivation clear in my initial post, because I was
> hoping to spare people some eye rolling.

I thought that in the kernel community we make decisions based on
technical merits rather than "contracts of support". 
Given that disabling the symbol saves near to nothing, the logical thing
to do is removing the symbol altogether.

Re: [PATCH 3/4] xen kconfig: add dom0 support help text

[Andrew Jones]

----- Original Message -----
> On Fri, 6 Jan 2012, Andrew Jones wrote:
> > > Almost all of the things which dom0 needs (e.g. PCI device
> > > management
> > > etc) is also required by a domU with passthrough enabled so the
> > > savings
> > > are really very slight.
> > > 
> > > We are talking less than 1k of code AFAICT, 319 bytes for
> > > arch/x86/xen/vga.o and 573 for drivers/xen/xenfs/xenstored.o plus
> > > whatever xen_register_gsi (a couple of dozen lines of code) adds
> > > to
> > > arch/x86/pci/xen.o. grep doesn't show CONFIG_XEN_DOM0 being used
> > > anywhere else. What savings do you see in practice from disabling
> > > just
> > > this symbol?
> > 
> > I completely agree that the saving are near none. The savings,
> > however,
> > aren't the only reason to drive the change. It's actually the
> > symbol
> > name itself. Unfortunately configs can be perceived as a contract
> > of
> > support, i.e. if feature xyz is enabled in the distro's config,
> > then
> > the distributor must have selected, and therefore will support,
> > said
> > feature.
> > 
> > I didn't make this motivation clear in my initial post, because I
> > was
> > hoping to spare people some eye rolling.
> 
> I thought that in the kernel community we make decisions based on
> technical merits rather than "contracts of support".

Sorry.

> Given that disabling the symbol saves near to nothing, the logical
> thing
> to do is removing the symbol altogether.
> 

I thought of that too. If the symbol just goes away, then my
non-technical requirement will be met and the functionality will
stay. I consider that a bigger win actually. I didn't suggest it
though, since I've never done any dom0 development, nor had any
consideration for dom0 code needs of the future. With
anti-credentials like that, I'd guess it'd be tougher for me to sell
the need to remove it, than it is for me to just make it
configurable.

Drew

Re: [Xen-devel] [PATCH 3/4] xen kconfig: add dom0 support help text

[Ian Campbell]

On Fri, 2012-01-06 at 09:26 +0000, Andrew Jones wrote:
> 
> ----- Original Message -----
> > On Fri, 2012-01-06 at 08:57 +0000, Andrew Jones wrote:
> > > Describe dom0 support in the config menu and supply help text for
> > > it.
> > 
> > This turns a non-user visible symbol into a user visible one.
> > Previously
> > if Xen was enabled and the other prerequisites were met you would get
> > dom0 support automatically -- do we really want to change that?
> > According to 6b0661a5e6fbf it was a deliberate decision to have it
> > this
> > way.
> 
> I think it's a necessary evil in order to give users the ability to
> compile kernels without the support. I know it doesn't make much sense
> for most users, but...

Who actually wants to do this though and why? Do you have a bug report
requesting this change?

Almost all of the things which dom0 needs (e.g. PCI device management
etc) is also required by a domU with passthrough enabled so the savings
are really very slight.

We are talking less than 1k of code AFAICT, 319 bytes for
arch/x86/xen/vga.o and 573 for drivers/xen/xenfs/xenstored.o plus
whatever xen_register_gsi (a couple of dozen lines of code) adds to
arch/x86/pci/xen.o. grep doesn't show CONFIG_XEN_DOM0 being used
anywhere else. What savings do you see in practice from disabling just
this symbol?

We need to weigh up the size change against the complexity of asking the
user yet another question, I'm not convinced the question is worth it on
balance.

> > 
> > BTW, you forgot a Signed-off-by and the appropriate CCs (please use
> > MAINTAINERS or ./scripts/get-maintainer.pl).
> > 
> 
> Sorry, I'll resend properly.

I've added those CC's to this reply too.

Ian.

> 
> Drew
> 
> > Ian.
> > 
> > > ---
> > >  arch/x86/xen/Kconfig |    7 ++++++-
> > >  1 files changed, 6 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > > index 26c731a..88862d5 100644
> > > --- a/arch/x86/xen/Kconfig
> > > +++ b/arch/x86/xen/Kconfig
> > > @@ -14,9 +14,14 @@ config XEN
> > >  	  Xen hypervisor.
> > >  
> > >  config XEN_DOM0
> > > -	def_bool y
> > > +	bool "Xen Initial Domain (Dom0) support"
> > > +	default y
> > >  	depends on XEN && PCI_XEN && SWIOTLB_XEN
> > >  	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
> > > +	help
> > > +	  This allows the kernel to be used for the initial Xen domain,
> > > +	  Domain0. This is a privileged guest that supplies backends
> > > +	  and is used to manage the other Xen domains.
> > >  
> > >  # Dummy symbol since people have come to rely on the
> > >  PRIVILEGED_GUEST
> > >  # name in tools.
> > 
> > 
> > 

Re: [PATCH 3/4] xen kconfig: add dom0 support help text

[Andrew Jones]

----- Original Message -----
> On Fri, 2012-01-06 at 09:26 +0000, Andrew Jones wrote:
> > 
> > ----- Original Message -----
> > > On Fri, 2012-01-06 at 08:57 +0000, Andrew Jones wrote:
> > > > Describe dom0 support in the config menu and supply help text
> > > > for
> > > > it.
> > > 
> > > This turns a non-user visible symbol into a user visible one.
> > > Previously
> > > if Xen was enabled and the other prerequisites were met you would
> > > get
> > > dom0 support automatically -- do we really want to change that?
> > > According to 6b0661a5e6fbf it was a deliberate decision to have
> > > it
> > > this
> > > way.
> > 
> > I think it's a necessary evil in order to give users the ability to
> > compile kernels without the support. I know it doesn't make much
> > sense
> > for most users, but...
> 
> Who actually wants to do this though and why? Do you have a bug
> report
> requesting this change?
> 

No bug for it. I'll explain the motivation below.

> Almost all of the things which dom0 needs (e.g. PCI device management
> etc) is also required by a domU with passthrough enabled so the
> savings
> are really very slight.
> 
> We are talking less than 1k of code AFAICT, 319 bytes for
> arch/x86/xen/vga.o and 573 for drivers/xen/xenfs/xenstored.o plus
> whatever xen_register_gsi (a couple of dozen lines of code) adds to
> arch/x86/pci/xen.o. grep doesn't show CONFIG_XEN_DOM0 being used
> anywhere else. What savings do you see in practice from disabling
> just
> this symbol?

I completely agree that the saving are near none. The savings, however,
aren't the only reason to drive the change. It's actually the symbol
name itself. Unfortunately configs can be perceived as a contract of
support, i.e. if feature xyz is enabled in the distro's config, then
the distributor must have selected, and therefore will support, said
feature.

I didn't make this motivation clear in my initial post, because I was
hoping to spare people some eye rolling.

> 
> We need to weigh up the size change against the complexity of asking
> the
> user yet another question, I'm not convinced the question is worth it
> on
> balance.
> 

Tons of questions aren't much fun to wade through, but I guess I'm
generally for a config menu complexity that is proportional to
(and controls) the kernel complexity.

Drew

> > > 
> > > BTW, you forgot a Signed-off-by and the appropriate CCs (please
> > > use
> > > MAINTAINERS or ./scripts/get-maintainer.pl).
> > > 
> > 
> > Sorry, I'll resend properly.
> 
> I've added those CC's to this reply too.
> 
> Ian.
> 
> > 
> > Drew
> > 
> > > Ian.
> > > 
> > > > ---
> > > >  arch/x86/xen/Kconfig |    7 ++++++-
> > > >  1 files changed, 6 insertions(+), 1 deletions(-)
> > > > 
> > > > diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > > > index 26c731a..88862d5 100644
> > > > --- a/arch/x86/xen/Kconfig
> > > > +++ b/arch/x86/xen/Kconfig
> > > > @@ -14,9 +14,14 @@ config XEN
> > > >  	  Xen hypervisor.
> > > >  
> > > >  config XEN_DOM0
> > > > -	def_bool y
> > > > +	bool "Xen Initial Domain (Dom0) support"
> > > > +	default y
> > > >  	depends on XEN && PCI_XEN && SWIOTLB_XEN
> > > >  	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
> > > > +	help
> > > > +	  This allows the kernel to be used for the initial Xen
> > > > domain,
> > > > +	  Domain0. This is a privileged guest that supplies backends
> > > > +	  and is used to manage the other Xen domains.
> > > >  
> > > >  # Dummy symbol since people have come to rely on the
> > > >  PRIVILEGED_GUEST
> > > >  # name in tools.
> > > 
> > > 
> > > 
> 
> 
> 

[PATCH 0/4] xen kconfig tweaks

[Andrew Jones]

This series is a collection of xen kconfig fixes and additions.

Andrew Jones (4):
  xen kconfig: keep XEN_XENBUS_FRONTEND builtin
  xen kconfig: relax INPUT_XEN_KBDDEV_FRONTEND deps
  xen kconfig: add dom0 support help text
  xen kconfig: describe xen tmem in the config menu

 arch/x86/xen/Kconfig       |    7 ++++++-
 drivers/input/misc/Kconfig |    2 +-
 drivers/video/Kconfig      |    1 +
 drivers/xen/Kconfig        |    4 ++--
 4 files changed, 10 insertions(+), 4 deletions(-)

-- 
1.7.7.5

[PATCH 3/4] xen kconfig: add dom0 support help text

[Andrew Jones]

Describe dom0 support in the config menu and supply help text for it.
---
 arch/x86/xen/Kconfig |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 26c731a..88862d5 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -14,9 +14,14 @@ config XEN
 	  Xen hypervisor.
 
 config XEN_DOM0
-	def_bool y
+	bool "Xen Initial Domain (Dom0) support"
+	default y
 	depends on XEN && PCI_XEN && SWIOTLB_XEN
 	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
+	help
+	  This allows the kernel to be used for the initial Xen domain,
+	  Domain0. This is a privileged guest that supplies backends
+	  and is used to manage the other Xen domains.
 
 # Dummy symbol since people have come to rely on the PRIVILEGED_GUEST
 # name in tools.
-- 
1.7.7.5

Re: [PATCH 3/4] xen kconfig: add dom0 support help text

[Ian Campbell]

On Fri, 2012-01-06 at 08:57 +0000, Andrew Jones wrote:
> Describe dom0 support in the config menu and supply help text for it.

This turns a non-user visible symbol into a user visible one. Previously
if Xen was enabled and the other prerequisites were met you would get
dom0 support automatically -- do we really want to change that?
According to 6b0661a5e6fbf it was a deliberate decision to have it this
way.

BTW, you forgot a Signed-off-by and the appropriate CCs (please use
MAINTAINERS or ./scripts/get-maintainer.pl).

Ian.

> ---
>  arch/x86/xen/Kconfig |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index 26c731a..88862d5 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -14,9 +14,14 @@ config XEN
>  	  Xen hypervisor.
>  
>  config XEN_DOM0
> -	def_bool y
> +	bool "Xen Initial Domain (Dom0) support"
> +	default y
>  	depends on XEN && PCI_XEN && SWIOTLB_XEN
>  	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
> +	help
> +	  This allows the kernel to be used for the initial Xen domain,
> +	  Domain0. This is a privileged guest that supplies backends
> +	  and is used to manage the other Xen domains.
>  
>  # Dummy symbol since people have come to rely on the PRIVILEGED_GUEST
>  # name in tools.

Re: [PATCH 3/4] xen kconfig: add dom0 support help text

[Andrew Jones]

----- Original Message -----
> On Fri, 2012-01-06 at 08:57 +0000, Andrew Jones wrote:
> > Describe dom0 support in the config menu and supply help text for
> > it.
> 
> This turns a non-user visible symbol into a user visible one.
> Previously
> if Xen was enabled and the other prerequisites were met you would get
> dom0 support automatically -- do we really want to change that?
> According to 6b0661a5e6fbf it was a deliberate decision to have it
> this
> way.

I think it's a necessary evil in order to give users the ability to
compile kernels without the support. I know it doesn't make much sense
for most users, but...

> 
> BTW, you forgot a Signed-off-by and the appropriate CCs (please use
> MAINTAINERS or ./scripts/get-maintainer.pl).
> 

Sorry, I'll resend properly.

Drew

> Ian.
> 
> > ---
> >  arch/x86/xen/Kconfig |    7 ++++++-
> >  1 files changed, 6 insertions(+), 1 deletions(-)
> > 
> > diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> > index 26c731a..88862d5 100644
> > --- a/arch/x86/xen/Kconfig
> > +++ b/arch/x86/xen/Kconfig
> > @@ -14,9 +14,14 @@ config XEN
> >  	  Xen hypervisor.
> >  
> >  config XEN_DOM0
> > -	def_bool y
> > +	bool "Xen Initial Domain (Dom0) support"
> > +	default y
> >  	depends on XEN && PCI_XEN && SWIOTLB_XEN
> >  	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
> > +	help
> > +	  This allows the kernel to be used for the initial Xen domain,
> > +	  Domain0. This is a privileged guest that supplies backends
> > +	  and is used to manage the other Xen domains.
> >  
> >  # Dummy symbol since people have come to rely on the
> >  PRIVILEGED_GUEST
> >  # name in tools.
> 
> 
>