Paravirtual framebuffer use xvc for xenconsole [4/6]

diff -r 5c452351be21 -r d49bc30b6b27 linux-2.6-xen-sparse/drivers/xen/console/console.c
@@ -57,19 +57,27 @@
 #include <asm/hypervisor.h>
 #include <xen/evtchn.h>
 #include <xen/xencons.h>
+#include <xen/xenbus.h>
 
 /*
  * Modes:
  *  '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 +93,8 @@ 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 +105,11 @@ 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;

@@ -194,11 +209,17 @@ static int __init xen_console_init(void)
 		kcons_info.write = kcons_write_dom0;
 	} else {
 		if (xc_mode == XC_DEFAULT)
-			xc_mode = XC_TTY;
+			xc_mode = XC_XVC;
 		kcons_info.write = kcons_write;
 	}
 
 	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)

@@ -265,7 +286,7 @@ void xencons_force_flush(void)
 /******************** User-space console driver (/dev/console) ************/
 
 #define DRV(_d)         (_d)
-#define DUMMY_TTY(_tty) ((xc_mode != XC_SERIAL) &&		\
+#define DUMMY_TTY(_tty) ((xc_mode != XC_SERIAL) && (xc_mode != XC_XVC) && \
 			 ((_tty)->index != (xc_num - 1)))
 
 static struct termios *xencons_termios[MAX_NR_CONSOLES];

@@ -584,7 +605,8 @@ static int __init xencons_init(void)
 
 	xencons_ring_init();
 
-	xencons_driver = alloc_tty_driver((xc_mode == XC_SERIAL) ?
+	xencons_driver = alloc_tty_driver(((xc_mode == XC_SERIAL) || 
+					   (xc_mode == XC_XVC)) ?
 					  1 : MAX_NR_CONSOLES);
 	if (xencons_driver == NULL)
 		return -ENOMEM;

@@ -604,6 +626,11 @@ 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       = 250;
+		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 = 1;