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* RE: [Fwd: Installing from distribution CDs]
@ 2005-02-09  0:11 Ian Pratt
  2005-02-09  1:00 ` Anthony Liguori
  0 siblings, 1 reply; 18+ messages in thread
From: Ian Pratt @ 2005-02-09  0:11 UTC (permalink / raw)
  To: Anthony Liguori; +Cc: Anthony Liguori, Jared Rhine, xen-devel, ian.pratt

Have we got concensus about how to handle this? (and hence a definitive
patch).

Requiring people to change there config command lines is probably OK
provided that we're making it closer to standard Linux behaviour.

Ian

> -----Original Message-----
> From: Anthony Liguori [mailto:anthony@codemonkey.ws] 
> Sent: 03 February 2005 02:17
> To: Ian Pratt
> Cc: Anthony Liguori; Jared Rhine; xen-devel@lists.sourceforge.net
> Subject: Re: [Xen-devel] [Fwd: Installing from distribution CDs]
> 
> Ian Pratt wrote:
> 
> >Thanks for looking into this. I wander if it's something to 
> do with the
> >way xen packages up the module as an initrd for dom0? Maybe 
> there's some
> >difference between an initrd and a ramdisk?
> >  
> >
> Didn't have time this afternoon but I was able to look into 
> it more this 
> evening and I found the culprit.  In arch/i386/kernel/setup.c 
> there was 
> the following line around L1363:
> 
>         ROOT_DEV = MKDEV(RAMDISK_MAJOR,0); 
> /*old_decode_dev(ORIG_ROOT_DEV);*/
> 
> This defaults the root device to /dev/ram0 instead of trying 
> to get it 
> from the boot loader.  I'm not sure why this there (perhaps a part of 
> early development?).  I've attached a patch that puts back the 
> old_decode_dev call and the behavior becomes exactly what 
> you'd expect: 
> if no root= is specified, initrd still works but if /linuxrc 
> exits you 
> get a VFS error because no root= is specified.
> 
> This is what Linux would normally do.
> 
> It's very important to note though that applying this patch 
> means that 
> if people had ramdisk=... lines in their configs and didn't have 
> root=/dev/ram0, their machines won't boot anymore.
> 
> A solution would be to add an initrd option to the configuration file 
> and have the ramdisk= option default the root device to /dev/ram0.
> 
> I've tested this patch on a couple day old copy of xen-unstable.  I'm 
> curious to know what the source of this was though because I 
> don't feel 
> very comfortable with just restoring something that was 
> obviously taken 
> out for a reason..
> 
> Regards,
> Anthony Liguori
> 
> Signed-off-by: Anthony Liguori
> 


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^ permalink raw reply	[flat|nested] 18+ messages in thread
* RE: [Fwd: Installing from distribution CDs]
@ 2005-02-09  1:47 Ian Pratt
  2005-02-09  2:11 ` Anthony Liguori
  0 siblings, 1 reply; 18+ messages in thread
From: Ian Pratt @ 2005-02-09  1:47 UTC (permalink / raw)
  To: Anthony Liguori; +Cc: Anthony Liguori, Jared Rhine, xen-devel, ian.pratt

 

> I posted a patch on 2/4.  Does anyone have a problem with that patch?

OK, so the only user-visible change is that root=/dev/ram0 is now
compulsory?

Ian

---
xen-unstable-orig/linux-2.6.10-xen-sparse/arch/xen/i386/kernel/setup.c
2005-01-25 22:29:18.000000000 -0600
+++ xen-unstable/linux-2.6.10-xen-sparse/arch/xen/i386/kernel/setup.c
2005-02-04 13:44:49.000000000 -0600
@@ -1360,7 +1360,10 @@
 		efi_enabled = 1;
 #endif
 
- 	ROOT_DEV = MKDEV(RAMDISK_MAJOR,0);
/*old_decode_dev(ORIG_ROOT_DEV);*/
+	/* This must be initialized to UNNAMED_MAJOR for ipconfig to
work
+	   properly.  Setting ROOT_DEV to default to /dev/ram0 breaks
initrd.
+	*/
+	ROOT_DEV = MKDEV(UNNAMED_MAJOR,0);
  	drive_info = DRIVE_INFO;
  	screen_info = SCREEN_INFO;
 	edid_info = EDID_INFO;
--- xen-unstable-orig/linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c
2005-01-25 22:29:10.000000000 -0600
+++ xen-unstable/linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c
2005-02-04 13:44:58.000000000 -0600
@@ -240,7 +240,9 @@
     boot_cpu_data.pgd_quick = cpu0_pgd_quicklist;
     boot_cpu_data.pte_quick = cpu0_pte_quicklist;
 
-    ROOT_DEV = MKDEV(RAMDISK_MAJOR,0);
+    /* This must be initialized to UNNAMED_MAJOR for ipconfig to work
+       properly.  Setting ROOT_DEV to default to /dev/ram0 breaks
initrd. */
+    ROOT_DEV = MKDEV(UNNAMED_MAJOR,0);
     memset(&drive_info, 0, sizeof(drive_info));
     memset(&screen_info, 0, sizeof(screen_info));
 


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^ permalink raw reply	[flat|nested] 18+ messages in thread
* RE: [Fwd: Installing from distribution CDs]
@ 2005-02-02 22:26 Ian Pratt
  2005-02-03  2:16 ` Anthony Liguori
  0 siblings, 1 reply; 18+ messages in thread
From: Ian Pratt @ 2005-02-02 22:26 UTC (permalink / raw)
  To: Anthony Liguori, Jared Rhine; +Cc: xen-devel, Ian Pratt

> Apparently what's happening is that at some point during the 
> domain boot
> process, Xen decides that the root device is /dev/ram0 if there is no
> root= command line on the kernel.  In
> init/do_mounts_rd.c:rd_load_image() if the ramdisk loads to what it
> thinks is the root device, the initrd actions are never taken.
> 
> Of course, patching that function to remove that check results in the
> same behavior.  I've not yet tracked down what's going on but 
> that's the problem.

Thanks for looking into this. I wander if it's something to do with the
way xen packages up the module as an initrd for dom0? Maybe there's some
difference between an initrd and a ramdisk?

Ian




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^ permalink raw reply	[flat|nested] 18+ messages in thread
* RE: [Fwd: Installing from distribution CDs]
@ 2005-02-02  8:51 Ian Pratt
  2005-02-02 11:31 ` Jared Rhine
  2005-02-02 14:57 ` Anthony Liguori
  0 siblings, 2 replies; 18+ messages in thread
From: Ian Pratt @ 2005-02-02  8:51 UTC (permalink / raw)
  To: Anthony Liguori, xen-devel; +Cc: niv



Anthony, I don't understand the need for the following patch:

--- xen-2.0-new/linux-2.6.9-xenU/init/main.c~	2005-01-11
14:43:52.000000000 -0600
+++ xen-2.0-new/linux-2.6.9-xenU/init/main.c	2005-01-11
14:44:46.168201000 -0600
@@ -745,6 +745,7 @@
 	if (execute_command)
 		run_init_process(execute_command);
 
+	run_init_process("/linuxrc");
 	run_init_process("/sbin/init");
 	run_init_process("/etc/init");
 	run_init_process("/bin/init");



Looking at the following fragment in initrd_load it should call
handle_initrd which looks for /linuxrc anyway:

                if (rd_load_image("/initrd.image") && ROOT_DEV !=
Root_RAM0) {
                        sys_unlink("/initrd.image");
                        handle_initrd();
                        return 1;
                }
 
Can we figure out what the root cause of the problem is? 

Thanks,
Ian


> -----Original Message-----
> From: xen-devel-admin@lists.sourceforge.net 
> [mailto:xen-devel-admin@lists.sourceforge.net] On Behalf Of 
> Anthony Liguori
> Sent: 11 January 2005 20:48
> To: xen-devel@lists.sourceforge.net
> Cc: niv@us.ibm.com
> Subject: [Xen-devel] [Fwd: Installing from distribution CDs]
> 
> Sorry, hit send instead of attach again.  Rest of patches included.
> -- 
> Anthony Liguori
> Samba, Linux/Windows Interoperability
> Linux Technology Center (LTC) - IBM Austin
> E-mail: aliguori@us.ibm.com
> Phone: (512) 838-1208
> Tie Line: 678-1208
> 


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^ permalink raw reply	[flat|nested] 18+ messages in thread
* [Fwd: Installing from distribution CDs]
@ 2005-01-11 20:48 Anthony Liguori
  0 siblings, 0 replies; 18+ messages in thread
From: Anthony Liguori @ 2005-01-11 20:48 UTC (permalink / raw)
  To: xen-devel; +Cc: niv

[-- Attachment #1: Type: text/plain, Size: 238 bytes --]

Sorry, hit send instead of attach again.  Rest of patches included.
-- 
Anthony Liguori
Samba, Linux/Windows Interoperability
Linux Technology Center (LTC) - IBM Austin
E-mail: aliguori@us.ibm.com
Phone: (512) 838-1208
Tie Line: 678-1208

[-- Attachment #2: Forwarded message - Installing from distribution CDs --]
[-- Type: message/rfc822, Size: 6036 bytes --]

[-- Attachment #2.1.1: Type: text/plain, Size: 1924 bytes --]

Hi,

I recently tried to see what it would take in Xen to install a
distribution from a CD in domain > 0.  Here's my findings along with a
couple patches I used to find this.  These patches are proof of concepts
and quite ugly.

1) initrd support

Xen currently implements the ramdisk option which seems to simply pull
in a gzip'd file to a ramdisk and set that as the root.  Looking at the
initrd code in the kernel and reading through the man page, initrd is a
bit more complicated than that.

Among other things, the initrd process will check for a /linuxrc file
and execute it.  After execution, it will remount a new root and then
fall through to the normal init process.

SLES-9 at least uses linuxrc.  I imagine most distros do since it was
added specifically to help out distros.

2) CDROM support.  SLES-9 at least expects to have been booted from a
CDROM and looks for a /proc/sys/ entry to find out where that CDROM is. 
Right now Xen doesn't really support CDROMs.

The attached patches add /linuxrc to the init list (this will at least
let you get a bit into the installation process), add an old hack from
2.4 Xen to enable at least some response to MULTISESSION ioctls
(otherwise isofs won't mount the device), and also add a CDROM entry to
/proc/sys for hdc1.

A couple questions did come up though:

1) why isn't xen using the Linux initrd code?  The man page says that
initrd has unspecified features.  My fear is that some distros rely on
these features so reusing the initrd code would probably be best.

2) Have there been thoughts on how removable devices like CDROMs are
going to be supported?

BTW, you have to increase the ramdisk size to 64MB and add support for
minix to the kernel in order to boot off of  SLES cd.

Regards,

-- 
Anthony Liguori
Samba, Linux/Windows Interoperability
Linux Technology Center (LTC) - IBM Austin
E-mail: aliguori@us.ibm.com
Phone: (512) 838-1208
Tie Line: 678-1208

[-- Attachment #2.1.2: xen-sles9-fakecd.diff --]
[-- Type: text/x-patch, Size: 3433 bytes --]

diff -ur xen-2.0/linux-2.6.9-xen-sparse/drivers/xen/blkfront/vbd.c xen-2.0-new/linux-2.6.9-xen-sparse/drivers/xen/blkfront/vbd.c
--- xen-2.0/linux-2.6.9-xen-sparse/drivers/xen/blkfront/vbd.c	2005-01-03 21:46:11.000000000 -0600
+++ xen-2.0-new/linux-2.6.9-xen-sparse/drivers/xen/blkfront/vbd.c	2005-01-05 14:08:26.000000000 -0600
@@ -31,6 +31,8 @@
 
 #include "block.h"
 #include <linux/blkdev.h>
+#include <linux/sysctl.h>
+#include <linux/proc_fs.h>
 
 /*
  * For convenience we distinguish between ide, scsi and 'other' (i.e.
@@ -281,6 +283,98 @@
 	return NULL;
 }
 
+#define CDROM_STR_SIZE 1000
+static char info[CDROM_STR_SIZE];
+
+int cdrom_sysctl_info(ctl_table *ctl, int write, struct file * filp,
+                           void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        int pos;
+	
+	if (!*lenp || (*ppos && !write)) {
+		*lenp = 0;
+		return 0;
+	}
+
+	pos = sprintf(info,
+		      "CD-ROM information, Id: cdrom.c 3.20 2003/12/17\n"
+		      "\ndrive name:\t\thdc1\n"
+		      "drive speed:\t\t40\n"
+		      "drive # of slots:\t1\n"
+		      "Can close tray:\t\t0\n"
+		      "Can open tray:\t\t0\n"
+		      "Can lock tray:\t\t0\n"
+		      "Can change speed:\t0\n"
+		      "Can select disk:\t0\n"
+		      "Can read multisession:\t0\n"
+		      "Can read MCN:\t\t0\n"
+		      "Reports media changed:\t0\n"
+		      "Can play audio:\t\t0\n"
+		      "Can write CD-R:\t\t0\n"
+		      "Can write CD-RW:\t0\n"
+		      "Can read DVD:\t\t0\n"
+		      "Can write DVD-R:\t0\n"
+		      "Can write DVD-RAM:\t0\n"
+		      "Can read MRW:\t\t0\n"
+		      "Can write MRW:\t\t0\n"
+		      "Can write RAM:\t\t0\n"
+		      "\n");
+		
+        return proc_dostring(ctl, write, filp, buffer, lenp, ppos);
+}
+
+/* Place files in /proc/sys/dev/cdrom */
+static ctl_table cdrom_table[] = {
+	{
+		.ctl_name	= DEV_CDROM_INFO,
+		.procname	= "info",
+		.data		= &info, 
+		.maxlen		= CDROM_STR_SIZE,
+		.mode		= 0444,
+		.proc_handler	= &cdrom_sysctl_info,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table cdrom_cdrom_table[] = {
+	{
+		.ctl_name	= DEV_CDROM,
+		.procname	= "cdrom",
+		.maxlen		= 0,
+		.mode		= 0555,
+		.child		= cdrom_table,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table cdrom_root_table[] = {
+#ifdef CONFIG_PROC_FS
+	{
+		.ctl_name	= CTL_DEV,
+		.procname	= "dev",
+		.maxlen		= 0,
+		.mode		= 0555,
+		.child		= cdrom_cdrom_table,
+	},
+#endif /* CONFIG_PROC_FS */
+	{ .ctl_name = 0 }
+};
+static struct ctl_table_header *cdrom_sysctl_header;
+
+static void cdrom_sysctl_register(void)
+{
+	static int initialized;
+
+	if (initialized == 1)
+		return;
+
+	cdrom_sysctl_header = register_sysctl_table(cdrom_root_table, 1);
+	if (cdrom_root_table->ctl_name && cdrom_root_table->child->de)
+		cdrom_root_table->child->de->owner = THIS_MODULE;
+
+	initialized = 1;
+}
+
 /*
  * xlvbd_init_device - initialise a VBD device
  * @disk:              a vdisk_t describing the VBD
@@ -323,13 +417,20 @@
 		goto out;
 	}
 
+	printk(KERN_ALERT "XenLinux: init of %d %s\n", device, gd->disk_name);
+
 	if (VDISK_READONLY(xd->info))
 		set_disk_ro(gd, 1); 
 
+	if (!strcmp(gd->disk_name, "hdc1")) {
+	  xd->info = VDISK_TYPE_CDROM;
+	}
+
 	/* Some final fix-ups depending on the device type */
 	switch (VDISK_TYPE(xd->info)) { 
 	case VDISK_TYPE_CDROM:
 		gd->flags |= GENHD_FL_REMOVABLE | GENHD_FL_CD; 
+		cdrom_sysctl_register();
 		/* FALLTHROUGH */
 	case VDISK_TYPE_FLOPPY: 
 	case VDISK_TYPE_TAPE:

[-- Attachment #3: xen-sles9-linuxrc.diff --]
[-- Type: text/x-patch, Size: 378 bytes --]

--- xen-2.0-new/linux-2.6.9-xenU/init/main.c~	2005-01-11 14:43:52.000000000 -0600
+++ xen-2.0-new/linux-2.6.9-xenU/init/main.c	2005-01-11 14:44:46.168201000 -0600
@@ -745,6 +745,7 @@
 	if (execute_command)
 		run_init_process(execute_command);
 
+	run_init_process("/linuxrc");
 	run_init_process("/sbin/init");
 	run_init_process("/etc/init");
 	run_init_process("/bin/init");

[-- Attachment #4: xen-sles9-multisession.diff --]
[-- Type: text/x-patch, Size: 1079 bytes --]

diff -ur xen-2.0/linux-2.6.9-xen-sparse/drivers/xen/blkfront/blkfront.c xen-2.0-new/linux-2.6.9-xen-sparse/drivers/xen/blkfront/blkfront.c
--- xen-2.0/linux-2.6.9-xen-sparse/drivers/xen/blkfront/blkfront.c	2005-01-03 21:46:09.000000000 -0600
+++ xen-2.0-new/linux-2.6.9-xen-sparse/drivers/xen/blkfront/blkfront.c	2005-01-05 14:22:11.000000000 -0600
@@ -236,6 +236,7 @@
 int blkif_ioctl(struct inode *inode, struct file *filep,
                 unsigned command, unsigned long argument)
 {
+	int i;
     /*  struct gendisk *gd = inode->i_bdev->bd_disk; */
 
     DPRINTK_IOCTL("command: 0x%x, argument: 0x%lx, dev: 0x%04x\n",
@@ -247,6 +248,12 @@
         /* return ENOSYS to use defaults */
         return -ENOSYS;
 
+    case CDROMMULTISESSION:
+        DPRINTK("FIXME: support multisession CDs later\n");
+        for ( i = 0; i < sizeof(struct cdrom_multisession); i++ )
+            if ( put_user(0, (byte *)(argument + i)) ) return -EFAULT;
+        return 0;
+
     default:
         printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
                command);

[-- Attachment #5: slesboot --]
[-- Type: text/plain, Size: 2870 bytes --]

#  -*- mode: python; -*-
#============================================================================
# Python configuration setup for 'xm create'.
# This script sets the parameters used when a domain is created using 'xm create'.
# You use a separate script for each domain you want to create, or 
# you can set the parameters for the domain on the xm command line.
#============================================================================

#----------------------------------------------------------------------------
# Kernel image file.
kernel = "/boot/vmlinuz-2.6.9-xenU"

# Optional ramdisk.
ramdisk = "/root/loader/initrd"

# The domain build function. Default is 'linux'.
#builder='linux'

# Initial memory allocation (in megabytes) for the new domain.
memory = 256

# A name for your domain. All domains must have different names.
name = "SLESBoot"

# Which CPU to start domain on? 
#cpu = -1   # leave to Xen to pick

#----------------------------------------------------------------------------
# Define network interfaces.

# Number of network interfaces. Default is 1.
#nics=1

# Optionally define mac and/or bridge for the network interfaces.
# Random MACs are assigned if not given.
#vif = [ 'mac=aa:00:00:00:00:11, bridge=xen-br0' ]

#----------------------------------------------------------------------------
# Define the disk devices you want the domain to have access to, and
# what you want them accessible as.
# Each disk entry is of the form phy:UNAME,DEV,MODE
# where UNAME is the device, DEV is the device name the domain will see,
# and MODE is r for read-only, w for read-write.

disk = [ 'phy:volumes/rhel3,sda1,w', 'file:/root/sles9.iso,hdc1,r' ]

#----------------------------------------------------------------------------
# Set the kernel command line for the new domain.
# You only need to define the IP parameters and hostname if the domain's
# IP config doesn't, e.g. in ifcfg-eth0 or via DHCP.
# You can use 'extra' to set the runlevel and custom environment
# variables used by custom rc scripts (e.g. VMID=, usr= ).

# Set if you want dhcp to allocate the IP address.
#dhcp="dhcp"
# Set netmask.
#netmask=
# Set default gateway.
#gateway=
# Set the hostname.
#hostname= "vm%d" % vmid

# Set root device.
#root = "/dev/sda2 rw"

# Root device for nfs.
#root = "/dev/nfs"
# The nfs server.
#nfs_server = '169.254.1.0'  
# Root directory on the nfs server.
#nfs_root   = '/full/path/to/root/directory'

# Sets runlevel 4.
extra = "4"

#----------------------------------------------------------------------------
# Set according to whether you want the domain restarted when it exits.
# The default is 'onreboot', which restarts the domain when it shuts down
# with exit code reboot.
# Other values are 'always', and 'never'.

#restart = 'onreboot'

#============================================================================

^ permalink raw reply	[flat|nested] 18+ messages in thread
end of thread, other threads:[~2005-02-09 22:56 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-02-09  0:11 [Fwd: Installing from distribution CDs] Ian Pratt
2005-02-09  1:00 ` Anthony Liguori
2005-02-09 22:56   ` Jared Rhine
  -- strict thread matches above, loose matches on Subject: below --
2005-02-09  1:47 Ian Pratt
2005-02-09  2:11 ` Anthony Liguori
2005-02-02 22:26 Ian Pratt
2005-02-03  2:16 ` Anthony Liguori
2005-02-03  4:07   ` Christian Limpach
2005-02-03  4:52     ` Anthony Liguori
2005-02-03 10:54       ` Christian Limpach
2005-02-02  8:51 Ian Pratt
2005-02-02 11:31 ` Jared Rhine
2005-02-02 15:03   ` Anthony Liguori
2005-02-02 18:39     ` Jared Rhine
2005-02-02 19:40       ` Anthony Liguori
2005-02-02 20:04         ` Anthony Liguori
2005-02-02 14:57 ` Anthony Liguori
2005-01-11 20:48 Anthony Liguori

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