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Amos Waterland

2006-Aug-02 21:42 UTC

[Xen-devel] Xen virtual console driver question

What is the plan for the future of the Xen virtual console driver?  Will
it continue to hijack /dev/ttyS0 or get its own device like /dev/xencons?

The reason I ask is that I need a single Linux kernel binary, including
one with builtin console=X command line arguments, to run on bare
hardware and as a dom0 under Xen.  Xen''s current approach is to disable
the physical serial port drivers in the Linux .config, which I need
enabled to run properly on bare JS21 blades.

I am currently using the below patch, but would really prefer not to.
It''s basic approach is to have the Xen virtual console driver react
"gracefully" in the case that a real serial driver has already
registered ttyS0-ttyS3.  It''s current behavior is to fail if the 8250
driver was initialized ahead of it, and console is lost.  In the process
I found a bug in Linux, and have included the patch for it since
otherwise the Xen driver initialization will succeed but with negative
side effects in the kobject subsystem.

What is the story?

---

diff -r 17aa29a18b08 arch/powerpc/configs/xen_maple_defconfig
--- a/arch/powerpc/configs/xen_maple_defconfig	Thu Jul 27 18:57:20 2006 -0400
+++ b/arch/powerpc/configs/xen_maple_defconfig	Mon Jul 31 21:04:17 2006 -0400
@@ -704,10 +704,18 @@ CONFIG_HW_CONSOLE=y
 #
 # Serial drivers
 #
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_8250_PCI=y
+CONFIG_SERIAL_8250_NR_UARTS=4
+CONFIG_SERIAL_8250_RUNTIME_UARTS=4
+# CONFIG_SERIAL_8250_EXTENDED is not set
 
 #
 # Non-8250 serial port support
 #
+CONFIG_SERIAL_CORE=y
+CONFIG_SERIAL_CORE_CONSOLE=y
 # CONFIG_SERIAL_ICOM is not set
 # CONFIG_SERIAL_JSM is not set
 CONFIG_UNIX98_PTYS=y
@@ -1307,7 +1315,7 @@ CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_BLKDEV_FRONTEND=y
 CONFIG_XEN_NETDEV_FRONTEND=y
 CONFIG_XEN_SCRUB_PAGES=y
-CONFIG_XEN_DISABLE_SERIAL=y
+# CONFIG_XEN_DISABLE_SERIAL is not set
 CONFIG_XEN_SYSFS=y
 # CONFIG_XEN_COMPAT_030002_AND_LATER is not set
 CONFIG_XEN_COMPAT_LATEST_ONLY=y
diff -r 17aa29a18b08 drivers/xen/console/console.c
--- a/drivers/xen/console/console.c	Thu Jul 27 18:57:20 2006 -0400
+++ b/drivers/xen/console/console.c	Mon Jul 31 21:04:17 2006 -0400
@@ -70,6 +70,7 @@
  */
 static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL } xc_mode = XC_DEFAULT;
 static int xc_num = -1;
+enum { XC_NUM_MAX = 8 };
 
 #ifdef CONFIG_MAGIC_SYSRQ
 static unsigned long sysrq_requested;
@@ -576,6 +577,7 @@ static int __init xencons_init(void)
 
 	xencons_ring_init();
 
+retry:
 	xencons_driver = alloc_tty_driver((xc_mode == XC_SERIAL) ?
 					  1 : MAX_NR_CONSOLES);
 	if (xencons_driver == NULL)
@@ -612,6 +614,15 @@ static int __init xencons_init(void)
 		       DRV(xencons_driver)->name_base);
 		put_tty_driver(xencons_driver);
 		xencons_driver = NULL;
+
+		/* Somebody, almost certainly the real serial port
+		   driver, registered ahead of us, so find the first
+		   unused minor.  */
+		if (xc_num <= XC_NUM_MAX) {
+		    xc_num++;
+		    goto retry;
+		}
+
 		return rc;
 	}
 
diff -r 17aa29a18b08 fs/char_dev.c
--- a/fs/char_dev.c	Thu Jul 27 18:57:20 2006 -0400
+++ b/fs/char_dev.c	Mon Jul 31 21:04:17 2006 -0400
@@ -111,10 +111,13 @@ __register_chrdev_region(unsigned int ma
 
 	for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
 		if ((*cp)->major > major ||
-		    ((*cp)->major == major && (*cp)->baseminor >=
baseminor))
+		    ((*cp)->major == major &&
+		     (((*cp)->baseminor >= baseminor) ||
+		      ((*cp)->baseminor + (*cp)->minorct > baseminor))))
 			break;
 	if (*cp && (*cp)->major == major &&
-	    (*cp)->baseminor < baseminor + minorct) {
+	    (((*cp)->baseminor < baseminor + minorct) ||
+	     ((*cp)->baseminor + (*cp)->minorct > baseminor))) {
 		ret = -EBUSY;
 		goto out;
 	}

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Ian Pratt

2006-Aug-02 23:20 UTC

head link

RE: [Xen-devel] Xen virtual console driver question

> I am currently using the below patch, but would really prefer not to.
> It''s basic approach is to have the Xen virtual console driver
react
> "gracefully" in the case that a real serial driver has already
> registered ttyS0-ttyS3.  It''s current behavior is to fail if the
8250
> driver was initialized ahead of it, and console is lost.  In the
process> I found a bug in Linux, and have included the patch for it since
> otherwise the Xen driver initialization will succeed but with negative
> side effects in the kobject subsystem.
It would certainly be good to split the linux bug fix out and submit it
upstream, and put it in our patches directory in the meantime.

Grabbing the next free minor aint pretty, but I agree its an
improvement.

Ian  

 > What is the story?
> 
> ---
> 
> diff -r 17aa29a18b08 arch/powerpc/configs/xen_maple_defconfig
> --- a/arch/powerpc/configs/xen_maple_defconfig	Thu Jul 27
18:57:20 2006 -> 0400
> +++ b/arch/powerpc/configs/xen_maple_defconfig	Mon Jul 31
21:04:17 2006 -> 0400
> @@ -704,10 +704,18 @@ CONFIG_HW_CONSOLE=y
>  #
>  # Serial drivers
>  #
> +CONFIG_SERIAL_8250=y
> +CONFIG_SERIAL_8250_CONSOLE=y
> +CONFIG_SERIAL_8250_PCI=y
> +CONFIG_SERIAL_8250_NR_UARTS=4
> +CONFIG_SERIAL_8250_RUNTIME_UARTS=4
> +# CONFIG_SERIAL_8250_EXTENDED is not set
> 
>  #
>  # Non-8250 serial port support
>  #
> +CONFIG_SERIAL_CORE=y
> +CONFIG_SERIAL_CORE_CONSOLE=y
>  # CONFIG_SERIAL_ICOM is not set
>  # CONFIG_SERIAL_JSM is not set
>  CONFIG_UNIX98_PTYS=y
> @@ -1307,7 +1315,7 @@ CONFIG_XEN_BLKDEV_FRONTEND=y
>  CONFIG_XEN_BLKDEV_FRONTEND=y
>  CONFIG_XEN_NETDEV_FRONTEND=y
>  CONFIG_XEN_SCRUB_PAGES=y
> -CONFIG_XEN_DISABLE_SERIAL=y
> +# CONFIG_XEN_DISABLE_SERIAL is not set
>  CONFIG_XEN_SYSFS=y
>  # CONFIG_XEN_COMPAT_030002_AND_LATER is not set
>  CONFIG_XEN_COMPAT_LATEST_ONLY=y
> diff -r 17aa29a18b08 drivers/xen/console/console.c
> --- a/drivers/xen/console/console.c	Thu Jul 27 18:57:20 2006 -0400
> +++ b/drivers/xen/console/console.c	Mon Jul 31 21:04:17 2006 -0400
> @@ -70,6 +70,7 @@
>   */
>  static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL } xc_mode >
XC_DEFAULT;
>  static int xc_num = -1;
> +enum { XC_NUM_MAX = 8 };
> 
>  #ifdef CONFIG_MAGIC_SYSRQ
>  static unsigned long sysrq_requested;
> @@ -576,6 +577,7 @@ static int __init xencons_init(void)
> 
>  	xencons_ring_init();
> 
> +retry:
>  	xencons_driver = alloc_tty_driver((xc_mode == XC_SERIAL) ?
>  					  1 : MAX_NR_CONSOLES);
>  	if (xencons_driver == NULL)
> @@ -612,6 +614,15 @@ static int __init xencons_init(void)
>  		       DRV(xencons_driver)->name_base);
>  		put_tty_driver(xencons_driver);
>  		xencons_driver = NULL;
> +
> +		/* Somebody, almost certainly the real serial port
> +		   driver, registered ahead of us, so find the first
> +		   unused minor.  */
> +		if (xc_num <= XC_NUM_MAX) {
> +		    xc_num++;
> +		    goto retry;
> +		}
> +
>  		return rc;
>  	}
> 
> diff -r 17aa29a18b08 fs/char_dev.c
> --- a/fs/char_dev.c	Thu Jul 27 18:57:20 2006 -0400
> +++ b/fs/char_dev.c	Mon Jul 31 21:04:17 2006 -0400
> @@ -111,10 +111,13 @@ __register_chrdev_region(unsigned int ma
> 
>  	for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
>  		if ((*cp)->major > major ||
> -		    ((*cp)->major == major && (*cp)->baseminor
>baseminor))
> +		    ((*cp)->major == major &&
> +		     (((*cp)->baseminor >= baseminor) ||
> +		      ((*cp)->baseminor + (*cp)->minorct > baseminor))))
>  			break;
>  	if (*cp && (*cp)->major == major &&
> -	    (*cp)->baseminor < baseminor + minorct) {
> +	    (((*cp)->baseminor < baseminor + minorct) ||
> +	     ((*cp)->baseminor + (*cp)->minorct > baseminor))) {
>  		ret = -EBUSY;
>  		goto out;
>  	}
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
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Keir Fraser

2006-Aug-03 08:01 UTC

head link

Re: [Xen-devel] Xen virtual console driver question

On 2 Aug 2006, at 22:42, Amos Waterland wrote:
> I am currently using the below patch, but would really prefer not to.
> It''s basic approach is to have the Xen virtual console driver
react
> "gracefully" in the case that a real serial driver has already
> registered ttyS0-ttyS3.  It''s current behavior is to fail if the
8250
> driver was initialized ahead of it, and console is lost.  In the 
> process
> I found a bug in Linux, and have included the patch for it since
> otherwise the Xen driver initialization will succeed but with negative
> side effects in the kobject subsystem.
>
> What is the story?
We need to obtain our own device number and then patch the driver. It''d
be great if someone else wants to look into this.

  -- Keir


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Amos Waterland

2006-Aug-03 23:07 UTC

head link

[Xen-devel] [PATCH] Virtual console driver on /dev/xvc0

On Thu, Aug 03, 2006 at 09:01:15AM +0100, Keir Fraser
wrote:> On 2 Aug 2006, at 22:42, Amos Waterland wrote:
> > I am currently using the below patch, but would really prefer not
> > to.  It''s basic approach is to have the Xen virtual console
driver
> > react "gracefully" in the case that a real serial driver has
already
> > registered ttyS0-ttyS3.  It''s current behavior is to fail if
the
> > 8250 driver was initialized ahead of it, and console is lost.  In
> > the process I found a bug in Linux, and have included the patch for
> > it since otherwise the Xen driver initialization will succeed but
> > with negative side effects in the kobject subsystem.
> >
> > What is the story?
> 
> We need to obtain our own device number and then patch the driver.
It''d
> be great if someone else wants to look into this.
> 
>  -- Keir
The below is the least invasive approach I can find, and works well on
my PPC64 blades: I can boot the exact same kernel on bare hardware and
as a dom0.  I am sure there will be distro concerns (such as
/etc/inittab and /etc/securetty), but I''d like to get the ball rolling
with this initial submission.  

Note that you have to put `xencons=xvc0'' in your Linux .config, and run
`mknod /dev/xvc0 c 232 0'' in your rootfs.

Signed-off-by: Amos Waterland <apw@us.ibm.com>

---

 drivers/xen/console/console.c |   19 +++++++++++++++++--
 include/linux/major.h         |    2 ++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff -r 17aa29a18b08 drivers/xen/console/console.c
--- a/drivers/xen/console/console.c	Thu Jul 27 18:57:20 2006 -0400
+++ b/drivers/xen/console/console.c	Thu Aug 03 18:57:28 2006 -0400
@@ -63,12 +63,14 @@
  *  ''xencons=off''  [XC_OFF]:     Console is disabled.
  *  ''xencons=tty''  [XC_TTY]:     Console attached to
''/dev/tty[0-9]+''.
  *  ''xencons=ttyS'' [XC_SERIAL]:  Console attached to
''/dev/ttyS[0-9]+''.
+ *  ''xencons=xvc''  [XC_XVC]:     Console attached to
''/dev/xvc[0-9]+''.
  *                 [XC_DEFAULT]: DOM0 -> XC_SERIAL ; all others ->
XC_TTY.
  * 
  * NB. In mode XC_TTY, we create dummy consoles for tty2-63. This suppresses
  * warnings from standard distro startup scripts.
  */
-static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL } xc_mode = XC_DEFAULT;
+static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL, XC_XVC } 
+    xc_mode = XC_DEFAULT;
 static int xc_num = -1;
 
 #ifdef CONFIG_MAGIC_SYSRQ
@@ -85,6 +87,8 @@ static int __init xencons_setup(char *st
 		xc_mode = XC_SERIAL;
 	else if (!strncmp(str, "tty", 3))
 		xc_mode = XC_TTY;
+	else if (!strncmp(str, "xvc", 3))
+		xc_mode = XC_XVC;
 	else if (!strncmp(str, "off", 3))
 		xc_mode = XC_OFF;
 
@@ -192,7 +196,7 @@ static int __init xen_console_init(void)
 		if (xc_mode == XC_DEFAULT)
 			xc_mode = XC_SERIAL;
 		kcons_info.write = kcons_write_dom0;
-		if (xc_mode == XC_SERIAL)
+		if (xc_mode == XC_SERIAL || xc_mode == XC_XVC)
 			kcons_info.flags |= CON_ENABLED;
 	} else {
 		if (xc_mode == XC_DEFAULT)
@@ -201,6 +205,12 @@ static int __init xen_console_init(void)
 	}
 
 	switch (xc_mode) {
+	case XC_XVC:
+		strcpy(kcons_info.name, "xvc");
+		if (xc_num == -1)
+			xc_num = 0;
+		break;
+
 	case XC_SERIAL:
 		strcpy(kcons_info.name, "ttyS");
 		if (xc_num == -1)
@@ -597,6 +607,11 @@ static int __init xencons_init(void)
 		DRV(xencons_driver)->name        = "ttyS";
 		DRV(xencons_driver)->minor_start = 64 + xc_num;
 		DRV(xencons_driver)->name_base   = 0 + xc_num;
+	} else if (xc_mode == XC_XVC) {
+		DRV(xencons_driver)->name        = "xvc";
+		DRV(xencons_driver)->major       = XEN_VIRTUAL_CONSOLE;
+		DRV(xencons_driver)->minor_start = 0;
+		DRV(xencons_driver)->name_base   = 0;
 	} else {
 		DRV(xencons_driver)->name        = "tty";
 		DRV(xencons_driver)->minor_start = xc_num;
diff -r 17aa29a18b08 include/linux/major.h
--- a/include/linux/major.h	Thu Jul 27 18:57:20 2006 -0400
+++ b/include/linux/major.h	Thu Aug 03 18:57:28 2006 -0400
@@ -166,4 +166,6 @@
 
 #define VIOTAPE_MAJOR		230
 
+#define XEN_VIRTUAL_CONSOLE	232
+
 #endif

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Keir Fraser

2006-Aug-04 07:55 UTC

head link

[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

On 4 Aug 2006, at 00:07, Amos Waterland wrote:
> The below is the least invasive approach I can find, and works well on
> my PPC64 blades: I can boot the exact same kernel on bare hardware and
> as a dom0.  I am sure there will be distro concerns (such as
> /etc/inittab and /etc/securetty), but I''d like to get the ball
rolling
> with this initial submission.
>
> Note that you have to put `xencons=xvc0'' in your Linux .config,
and run
> `mknod /dev/xvc0 c 232 0'' in your rootfs.
>
> Signed-off-by: Amos Waterland <apw@us.ibm.com>
How did you pick the major? Is there a process for allocating one (I 
think our bklock-device major is now official)? Could we use a more 
dynamic (e.g., udev-based) scheme to avoid locking down 1/256th of the 
8-bit major space for this?

  -- Keir


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Jimi Xenidis

2006-Aug-04 13:01 UTC

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Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0

On Aug 3, 2006, at 7:07 PM, Amos Waterland wrote:
>
> The below is the least invasive approach I can find, and works well on
> my PPC64 blades: I can boot the exact same kernel on bare hardware and
> as a dom0.  I am sure there will be distro concerns (such as
> /etc/inittab and /etc/securetty), but I''d like to get the ball
rolling
> with this initial submission.
Most modern distros are getty''ing /dev/console, and your logic wires  
that up correctly.
So for recent kernels I do not see why we would want to maintain the  
older ones.

Kier, perhaps we can make this:
   - CONFIG_XEN_XVC=y to make it the default
   - CONFIG_XEN_XVC_ONLY=y and depricate the ttySn and ttyn

And any distro that is broken by XVC can keep the backward compat.
-JX


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Jeremy Katz

2006-Aug-04 14:23 UTC

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Re: [Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

On Fri, 2006-08-04 at 08:55 +0100, Keir Fraser wrote:> On 4 Aug 2006, at 00:07, Amos Waterland wrote:
> 
> > The below is the least invasive approach I can find, and works well on
> > my PPC64 blades: I can boot the exact same kernel on bare hardware and
> > as a dom0.  I am sure there will be distro concerns (such as
> > /etc/inittab and /etc/securetty), but I''d like to get the
ball rolling
> > with this initial submission.
> >
> > Note that you have to put `xencons=xvc0'' in your Linux
.config, and run
> > `mknod /dev/xvc0 c 232 0'' in your rootfs.
> >
> > Signed-off-by: Amos Waterland <apw@us.ibm.com>
> 
> How did you pick the major? Is there a process for allocating one (I 
> think our bklock-device major is now official)? Could we use a more 
> dynamic (e.g., udev-based) scheme to avoid locking down 1/256th of the 
> 8-bit major space for this?
The instructions for getting a major are available at
http://www.lanana.org/docs/device-list/instructions.txt and the official
list of majors/minors is at
http://www.lanana.org/docs/device-list/devices-2.6+.txt.

char major 232 is already taken for biometrics.  There''s no reason that
we shouldn''t be able to get a minor (or a couple, if it makes more
sense
to have more than one xvc device in some case) char devices in the
low-density serial console region (char major 204)

Jeremy


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Keir Fraser

2006-Aug-04 14:31 UTC

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Re: [Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

On 4/8/06 3:23 pm, "Jeremy Katz" <katzj@redhat.com> wrote:
>> How did you pick the major? Is there a process for allocating one (I
>> think our bklock-device major is now official)? Could we use a more
>> dynamic (e.g., udev-based) scheme to avoid locking down 1/256th of the
>> 8-bit major space for this?
> 
> The instructions for getting a major are available at
> http://www.lanana.org/docs/device-list/instructions.txt and the official
> list of majors/minors is at
> http://www.lanana.org/docs/device-list/devices-2.6+.txt.
> 
> char major 232 is already taken for biometrics.  There''s no reason
that
> we shouldn''t be able to get a minor (or a couple, if it makes more
sense
> to have more than one xvc device in some case) char devices in the
> low-density serial console region (char major 204)
That page makes it sound like the static allocation of device numbers is
obsolete. Is there some preferred dynamic method now?

 -- Keir



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Jeremy Katz

2006-Aug-04 14:34 UTC

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Re: [Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

On Fri, 2006-08-04 at 15:31 +0100, Keir Fraser wrote:> On 4/8/06 3:23 pm, "Jeremy Katz" <katzj@redhat.com> wrote:
> >> How did you pick the major? Is there a process for allocating one
(I
> >> think our bklock-device major is now official)? Could we use a
more
> >> dynamic (e.g., udev-based) scheme to avoid locking down 1/256th of
the
> >> 8-bit major space for this?
> > 
> > The instructions for getting a major are available at
> > http://www.lanana.org/docs/device-list/instructions.txt and the
official
> > list of majors/minors is at
> > http://www.lanana.org/docs/device-list/devices-2.6+.txt.
> > 
> > char major 232 is already taken for biometrics.  There''s no
reason that
> > we shouldn''t be able to get a minor (or a couple, if it makes
more sense
> > to have more than one xvc device in some case) char devices in the
> > low-density serial console region (char major 204)
> 
> That page makes it sound like the static allocation of device numbers is
> obsolete. Is there some preferred dynamic method now?
Using udev or similar is the way of doing things dynamically.  But there
are still a number of areas where static major/minor is strongly
desirable and consoles are one of those areas.  

Jeremy


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Amos Waterland

2006-Aug-04 17:15 UTC

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[Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

Use the low-density serial console major and the next free minor
according to the Lanana.  Since it would be awkward to say
''xencons=xvc187'', use name_base to allow /dev/xvc0 to be 
major/minor 204/187.

To use, put `xencons=xvc0'' in your Linux .config, and run
`mknod /dev/xvc0 c 204 187'' in your rootfs.  Built and booted up to
nfsroot on a JS21 ppc64 blade both on bare hardware and as a dom0.

Signed-off-by: Amos Waterland <apw@us.ibm.com>

---

 drivers/xen/console/console.c |   29 +++++++++++++++++++++++++++--
 include/linux/major.h         |    1 +
 2 files changed, 28 insertions(+), 2 deletions(-)

diff -r 17aa29a18b08 drivers/xen/console/console.c
--- a/drivers/xen/console/console.c	Thu Jul 27 18:57:20 2006 -0400
+++ b/drivers/xen/console/console.c	Fri Aug 04 13:04:06 2006 -0400
@@ -63,13 +63,20 @@
  *  ''xencons=off''  [XC_OFF]:     Console is disabled.
  *  ''xencons=tty''  [XC_TTY]:     Console attached to
''/dev/tty[0-9]+''.
  *  ''xencons=ttyS'' [XC_SERIAL]:  Console attached to
''/dev/ttyS[0-9]+''.
+ *  ''xencons=xvc''  [XC_XVC]:     Console attached to
''/dev/xvc[0-9]+''.
  *                 [XC_DEFAULT]: DOM0 -> XC_SERIAL ; all others ->
XC_TTY.
  * 
  * NB. In mode XC_TTY, we create dummy consoles for tty2-63. This suppresses
  * warnings from standard distro startup scripts.
  */
-static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL } xc_mode = XC_DEFAULT;
+static enum { XC_OFF, XC_DEFAULT, XC_TTY, XC_SERIAL, XC_XVC } 
+    xc_mode = XC_DEFAULT;
 static int xc_num = -1;
+
+/* If we are in XC_XVC mode (a virtual console at /dev/xvcX), we need to
+ * comply with Lanana and use a minor under the low density serial major.
+ */
+#define XEN_XVC_MINOR 187
 
 #ifdef CONFIG_MAGIC_SYSRQ
 static unsigned long sysrq_requested;
@@ -85,6 +92,8 @@ static int __init xencons_setup(char *st
 		xc_mode = XC_SERIAL;
 	else if (!strncmp(str, "tty", 3))
 		xc_mode = XC_TTY;
+	else if (!strncmp(str, "xvc", 3))
+		xc_mode = XC_XVC;
 	else if (!strncmp(str, "off", 3))
 		xc_mode = XC_OFF;
 
@@ -95,6 +104,11 @@ static int __init xencons_setup(char *st
 			xc_num = n;
 		break;
 	case XC_TTY:
+		n = simple_strtol(str+3, &q, 10);
+		if (q > (str + 3))
+			xc_num = n;
+		break;
+	case XC_XVC:
 		n = simple_strtol(str+3, &q, 10);
 		if (q > (str + 3))
 			xc_num = n;
@@ -192,7 +206,7 @@ static int __init xen_console_init(void)
 		if (xc_mode == XC_DEFAULT)
 			xc_mode = XC_SERIAL;
 		kcons_info.write = kcons_write_dom0;
-		if (xc_mode == XC_SERIAL)
+		if (xc_mode == XC_SERIAL || xc_mode == XC_XVC)
 			kcons_info.flags |= CON_ENABLED;
 	} else {
 		if (xc_mode == XC_DEFAULT)
@@ -201,6 +215,12 @@ static int __init xen_console_init(void)
 	}
 
 	switch (xc_mode) {
+	case XC_XVC:
+		strcpy(kcons_info.name, "xvc");
+		if (xc_num == -1)
+			xc_num = 0;
+		break;
+
 	case XC_SERIAL:
 		strcpy(kcons_info.name, "ttyS");
 		if (xc_num == -1)
@@ -597,6 +617,11 @@ static int __init xencons_init(void)
 		DRV(xencons_driver)->name        = "ttyS";
 		DRV(xencons_driver)->minor_start = 64 + xc_num;
 		DRV(xencons_driver)->name_base   = 0 + xc_num;
+	} else if (xc_mode == XC_XVC) {
+		DRV(xencons_driver)->name        = "xvc";
+		DRV(xencons_driver)->major       = LOW_DENS_SERIAL_MAJOR;
+		DRV(xencons_driver)->minor_start = XEN_XVC_MINOR;
+		DRV(xencons_driver)->name_base   = xc_num;
 	} else {
 		DRV(xencons_driver)->name        = "tty";
 		DRV(xencons_driver)->minor_start = xc_num;
diff -r 17aa29a18b08 include/linux/major.h
--- a/include/linux/major.h	Thu Jul 27 18:57:20 2006 -0400
+++ b/include/linux/major.h	Fri Aug 04 13:04:06 2006 -0400
@@ -158,6 +158,7 @@
 
 #define MSR_MAJOR		202
 #define CPUID_MAJOR		203
+#define LOW_DENS_SERIAL_MAJOR	204
 
 #define OSST_MAJOR		206	/* OnStream-SCx0 SCSI tape */
 

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Jeremy Katz

2006-Aug-04 17:21 UTC

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Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

On Fri, 2006-08-04 at 13:15 -0400, Amos Waterland wrote:> Use the low-density serial console major and the next free minor
> according to the Lanana.  Since it would be awkward to say
> ''xencons=xvc187'', use name_base to allow /dev/xvc0 to be 
> major/minor 204/187.
Please go through the process of sending mail to lanana and getting an
officially assigned number.  Once that''s done and it''s being
used, this
should be okay but not before.

Jeremy


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Jimi Xenidis

2006-Aug-04 17:22 UTC

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[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

On Aug 4, 2006, at 1:15 PM, Amos Waterland wrote:>
> diff -r 17aa29a18b08 drivers/xen/console/console.c
> --- a/drivers/xen/console/console.c	Thu Jul 27 18:57:20 2006 -0400
> +++ b/drivers/xen/console/console.c	Fri Aug 04 13:04:06 2006 -0400
> @@ -63,13 +63,20 @@
>   *  ''xencons=off''  [XC_OFF]:     Console is disabled.
>   *  ''xencons=tty''  [XC_TTY]:     Console attached to
''/dev/tty[0-9]
> +''.
>   *  ''xencons=ttyS'' [XC_SERIAL]:  Console attached to
''/dev/ttyS
> [0-9]+''.
> + *  ''xencons=xvc''  [XC_XVC]:     Console attached to
''/dev/xvc[0-9]
> +''.
>   *                 [XC_DEFAULT]: DOM0 -> XC_SERIAL ; all others ->  
> XC_TTY.

Can''t we switch the DomU''s to XVC as well?

-JX


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Jeremy Katz

2006-Aug-04 17:37 UTC

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[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

On Fri, 2006-08-04 at 13:22 -0400, Jimi Xenidis wrote:> On Aug 4, 2006, at 1:15 PM, Amos Waterland wrote:
> > diff -r 17aa29a18b08 drivers/xen/console/console.c
> > --- a/drivers/xen/console/console.c	Thu Jul 27 18:57:20 2006 -0400
> > +++ b/drivers/xen/console/console.c	Fri Aug 04 13:04:06 2006 -0400
> > @@ -63,13 +63,20 @@
> >   *  ''xencons=off''  [XC_OFF]:     Console is
disabled.
> >   *  ''xencons=tty''  [XC_TTY]:     Console attached
to ''/dev/tty[0-9]
> > +''.
> >   *  ''xencons=ttyS'' [XC_SERIAL]:  Console attached
to ''/dev/ttyS
> > [0-9]+''.
> > + *  ''xencons=xvc''  [XC_XVC]:     Console attached
to ''/dev/xvc[0-9]
> > +''.
> >   *                 [XC_DEFAULT]: DOM0 -> XC_SERIAL ; all others
->
> > XC_TTY.
>
> Can''t we switch the DomU''s to XVC as well?
I would expect that''s what we want to do.  At which point, the current
xenconsole should behave like a serial console (stop taking
over /dev/tty*, etc) and we can hopefully have the xenfb stuff to
provide a more full-featured console for domUs

Jeremy


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Amos Waterland

2006-Aug-04 17:37 UTC

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Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

On Fri, Aug 04, 2006 at 01:21:39PM -0400, Jeremy Katz
wrote:> On Fri, 2006-08-04 at 13:15 -0400, Amos Waterland wrote:
> > Use the low-density serial console major and the next free minor
> > according to the Lanana.  Since it would be awkward to say
> > ''xencons=xvc187'', use name_base to allow /dev/xvc0
to be
> > major/minor 204/187.
> 
> Please go through the process of sending mail to lanana and getting an
> officially assigned number.  Once that''s done and it''s
being used, this
> should be okay but not before.
I can send this to device@lanana.org.  Keir, is this all right with you?

---

The Xen virtual console driver would like to request the following.

204 char	    Low-density serial ports
 187 = /dev/xvc0     Xen virtual console device


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Keir Fraser

2006-Aug-04 19:21 UTC

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[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

On 4/8/06 6:15 pm, "Amos Waterland" <apw@us.ibm.com> wrote:
> Use the low-density serial console major and the next free minor
> according to the Lanana.  Since it would be awkward to say
> ''xencons=xvc187'', use name_base to allow /dev/xvc0 to be
> major/minor 204/187.
> 
> To use, put `xencons=xvc0'' in your Linux .config, and run
> `mknod /dev/xvc0 c 204 187'' in your rootfs.  Built and booted up
to
> nfsroot on a JS21 ppc64 blade both on bare hardware and as a dom0.
> 
> Signed-off-by: Amos Waterland <apw@us.ibm.com>
It''d be polite to email Lanana and request the minor to be allocated
for us.
Could you do that, please? Apart from that the patch looks fine to me, but I
think we should wait for the major/minor to be allocated before we apply it.

 -- Keir



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Keir Fraser

2006-Aug-04 19:23 UTC

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[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

On 4/8/06 6:22 pm, "Jimi Xenidis" <jimix@watson.ibm.com> wrote:
>> diff -r 17aa29a18b08 drivers/xen/console/console.c
>> --- a/drivers/xen/console/console.c Thu Jul 27 18:57:20 2006 -0400
>> +++ b/drivers/xen/console/console.c Fri Aug 04 13:04:06 2006 -0400
>> @@ -63,13 +63,20 @@
>>   *  ''xencons=off''  [XC_OFF]:     Console is
disabled.
>>   *  ''xencons=tty''  [XC_TTY]:     Console attached to
''/dev/tty[0-9]
>> +''.
>>   *  ''xencons=ttyS'' [XC_SERIAL]:  Console attached to
''/dev/ttyS
>> [0-9]+''.
>> + *  ''xencons=xvc''  [XC_XVC]:     Console attached to
''/dev/xvc[0-9]
>> +''.
>>   *                 [XC_DEFAULT]: DOM0 -> XC_SERIAL ; all others
->
>> XC_TTY.
> 
> 
> Can''t we switch the DomU''s to XVC as well?
Once the patch is applied and tested out, making xvc the default (or maybe
the only choice) probably does make sense.

 -- Keir



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Keir Fraser

2006-Aug-04 19:23 UTC

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Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

On 4/8/06 6:37 pm, "Amos Waterland" <apw@us.ibm.com> wrote:
>> Please go through the process of sending mail to lanana and getting an
>> officially assigned number.  Once that''s done and
it''s being used, this
>> should be okay but not before.
> 
> I can send this to device@lanana.org.  Keir, is this all right with you?
Yes, please!

 -- Keir



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Xen devel - Aug 2006 - Xen virtual console driver question

[Xen-devel] Xen virtual console driver question

RE: [Xen-devel] Xen virtual console driver question

Re: [Xen-devel] Xen virtual console driver question

[Xen-devel] [PATCH] Virtual console driver on /dev/xvc0

[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0

Re: [Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

Re: [Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

Re: [Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0

[Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)

[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

[Xen-devel] Re: [PATCH] Virtual console driver on /dev/xvc0 (take two)

Re: [Xen-devel] [PATCH] Virtual console driver on /dev/xvc0 (take two)