Setting up Qemu

[nick65go]

FYI: I saw that (in both x86 and x86_64 versions) the exfat.ko.gz is unusually placed in drivers, instead of fs (file system) branch, ex: /modules.gz\modules\lib\modules\6.1.2-tinycore\kernel\drivers\scsi\exfat\.

In qemu (ver 3.1) booting TC14 x86_64 with VIRTIO options, both cdrom and hda, the /cde is not used so Xfbdev is not automatically started, because /dev/vda# is not mounted.

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qemu-system-x86_64 -accel kvm -machine q35 -cpu max -m 128M -vga virtio -kernel vmlinuz64 -initrd MyCore.gz -drive file=MyDVD.iso,if=virtio,media=cdrom,readonly=on,index=1 -drive file=Mydisk.qcow2,if=virtio,media=disk,index=2 -boot c -append "vga=ask nozram noswap root=/ init=/init"
Maybe I missed some initial driver parameters? because after booting I can mount cdrom from /mnt/vda and hdd-disk from /dev/vdb1. OR from /dev/sr0 an /dev/sda1 if I did not use virtio simulation.

EDIT: maybe is my mistake, /cde folder can be only on booting device, but not on another device.

[Rich]

Hi nick65go

... EDIT: maybe is my mistake, /cde folder can be only on booting device, but not on another device.

I don't think that is true.

tc-config  calls  tce-setup  to load extensions.
tce-setup  contains the following:

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# Finally check for CD Extensions if requested
if [ "$CDE" ]; then
        # Some cd drives are slow - if cde was requested, wait for udev to settle
        [ ! -s /etc/sysconfig/cdroms ] && udevadm settle --timeout 5

        if [ -s /etc/sysconfig/cdroms ]; then
                for DEV in `cat /etc/sysconfig/cdroms`; do
                        process_CD
                done
        fi
fi

# If nothing loaded then also check for pseudo CD, e.g., isohybrid
if [ "$CDE" -a -z "$CDELIST" ]; then
        sleep 5
        DEV="$(autoscan 'cde' 'd')"
        process_CD
fiIf it doesn't find any CDs, then it scans the rest of the system for a device
containing a  /cde  directory.

In order for that to take place, you need to pass the  cde  boot code. I don't
see  cde  anywhere in your  qemu  command.

[nick65go]

In order for that to take place, you need to pass the  cde  boot code. I don't see  cde  anywhere in your  qemu  command.

Rich, you spot it! Thank you.
PS: I am in the process to rename the (internal) tc functions and subroutines, replacing abc() with _abc(),
same for tc variables, so iset var=blah become set tc_var=blah; and is also clear (for me) if is a function or a variable, etc.
so is self-documented then, and I "know" that is not an external command from /bin, /usr/bin (and busybox/gnu_tools, toybox). In the process I involuntary "destroyed" some scripts.

[nick65go]

For clarity, to do not confuse the audience, I am back to virgin files (vmlinuz, rootfs.gz, modules.gz, *.tcz), so Xvesa for now.
[BUT it is the same small "problem" as with Xfbdev running in both in x86 and x86_64];

I concatenated rootfs.gz + modules.gz into MyCore,gz (because I can not have multiple -initrd parameters in qemu  ).
I created sda1.qcow2 file, from linux I formatted as ext2 and mounted [so it has NO PARTITIONS] and I populated its /tce/optional folder with virgin *.tcz and *tcz.dep, and I have /tce/onboot.lst etc.

case 1: booting with "legacy" -hda is working, Xvesa shows up automatically.

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qemu-system-i386.exe -machine q35 -cpu max -m 128M -vga virtio -kernel vmlinuz -initrd Mycore.gz -hda sda1.qcow2

case 2: booting with "Virtio" vda is NOT working by default, only manually.

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qemu-system-i386.exe -machine q35 -cpu max -m 128M -vga virtio -kernel vmlinuz -initrd Mycore.gz -drive file=sda1.qcow2,if=virtio,media=disk
In cat /etc/fstab I have the mount point /mnt/vda mapped to /dev/vda, OK. But the mount command shows that /dev/vda is not mounted yet. So of course tczs are not loaded, and Xvesa is not shown.
I tried even with individual -append cases, like tce=vda, tce=/mnt/vda, tce=/dev/vda etc. No success. 

The bug: the virgin scripts are focused MAINLY on strings like sda* but not vda*. This happens with VIRTIO and with sda.qcow2 partitioned or not.

[nick65go]

As for virtio disks, it's quite possible some scripts are missing vda* cases.

Right! The culprit section may be in /etc/init.d/tc-config ? with booting variable tcvd=something;
but I am rusty with shell variable truncating... I have no success with it like tcvd=/dev/vda/tce.

Today is near no point to simulate old-pseudo-real devices, when Qemu (yes, 3.1  ) is so advanced in Virtio everything (blocks, devices, controllers, network-cards, files-share, video, cpu, etc). A trimmed-down kernel with just virtio drivers, eventually built-in, (and possible without spectre mitigations) will be nice to have.

PS: it is just for fun, to remind me the flow: boot-loader -> kernel -> shell (+ libs)  -> udev -> mounts -> login.

[Rich]

Hi nick65go

... PS: it is just for fun, to remind me the flow: boot-loader -> kernel -> shell (+ libs)  -> udev -> mounts -> login.

This appears to be accurate:
https://forum.tinycorelinux.net/index.php/topic,22020.0.html

[Rich]

Hi nick65go
If you run this:

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autoscan-devicesdoes it find your virtual disk?

[nick65go]

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autoscan-devicesdoes it find your virtual disk?

Yes, result is "vda"

[nick65go]

Wow, I think I found the "wrong" instruction; is in the /etc/init,d/tc-functions, at lines 91 and 106:

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MOUNTPOINT="$(grep -i ^$D2\  /etc/mtab | awk '{print $2}' | head -n 1)"I think that is should be $D2, without "\"; or to be $D2\s; [where \s means space in regex].

I can execute code

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D2=/dev/vda ABC="$(grep -i ^$D2 /etc/fstab)" ; echo $ABCresulting in ABC="/dev/vda" from /etc/fstab, or resulting ABC="" from /etc/mtab.

But with

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D2=/dev/vda ABC="$(grep -i ^$D2\  /etc/fstab)" ; echo $ABCI stay in a loop forever.

[Rich]

Hi nick65go

... I think that is should be $D2, without "\"; or to be $D2\s; [where \s means space in regex]. ...

No, it is correct as written. The "\ " tells grep to include a trailing space
as part of the search term. If you look at:

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^$D2\  /etc
123456789there are 2 spaces between  \  and  /  in positions 6 and 7.

The first space is part of the search term and the second
separates search term from the file to be searched.

As near as I can tell,  find_mountpoint  works correctly:

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tc@E310:~$ for DEVICE in `autoscan-devices`; do find_mountpoint $DEVICE; echo $MOUNTPOINT; done
/mnt/sda2
/mnt/sda7
/mnt/sda3
/mnt/sda1
/mnt/sda6
/mnt/sdb1
tc@E310:~$
Rename your  /tce  directory to  /cde  and add the  cde  boot code.
The  cde  directory must be in the root of the drive.
Remove any  tce  boot codes.
It should be able to find the  /cde  directory on its own.

[nick65go]

Hi Rich, thanks for the feed-back.
For clarification, lets forget about "cde" boot code/parameter.
Lets focus only on /tce folder in "disk" /dev/vda, in partition "vda" (not vda1, because I have no partition) with boot code tcvd=/dev/vda (or tcvd=vda/whatever, etc)

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#Check for Virtual Hard Drive
if [ -n "$TCVD" ]; then
    wait $fstab_pid
    TCVD="${TCVD#/}"
    TCVD="${TCVD#dev/}"
    TCVD_DEVICE="${TCVD%%/*}"
    TCVD_LOOPFILE="${TCVD#*/}"
    if [ "$TCVD_DEVICE" == "$TCVD_LOOPFILE" ]; then
        TCVD_DEVICE="$(tc_autoscan $TCVD_LOOPFILE 'f')"
    fi   
    PARTITION="${TCVD_DEVICE##/dev/}"
    find_mountpoint "$PARTITION"
    if [ -n "$MOUNTPOINT" ]; then
        [ "$MOUNTED" == "yes" ] || /bin/mount "$MOUNTPOINT"
        usleep_progress
        if [ -f "$MOUNTPOINT"/"$TCVD_LOOPFILE" ]; then
            [ -d /mnt/tcvd ] || /bin/mkdir /mnt/tcvd
            ln -sf "$MOUNTPOINT"/"$TCVD_LOOPFILE" /dev/tcvd
            printf "/dev/tcvd \t/mnt/tcvd \text2\tloop\t0 0 #Added by TC\n" >> /etc/fstab
            sync
        fi
    fiI started with TCVD=/dev/vda, then TCVD_DEVICE=vda and TCVD_LOOPFILE=vda;
then there I had a problem with $MOUNTPOINT==" ";
and the   if [ -n "$MOUNTPOINT" ]; then bypass all. Hm..
I was running each instruction step by step, but last time it was something like inside find_mountpoint "$PARTITION" it struggled with the grep - i ^$D2, when $D2 was /dev/vda.

PS: if you have time, could you do the same, run step by step, to reproduce my findings for $D2=/dev/vda in that part of code, to see what I mean?

[nick65go]

"find_mountpoint vda" works correctly

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. /etc/init.d/tc-functions; MOUNTED="fake"; find_mountpoint vda ; echo $MOUNTPOINT $ MOUNTEDwill return internal MOUNTPOINT=/mnt/vda and internal MOUNTED=no (or my external MOUNTED=fake)

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#Check for Virtual Hard Drive
if [ -n "$TCVD" ]; then                             # TCVD=/dev/vda/tce/abc
    wait $fstab_pid
    TCVD="${TCVD#/}"                            # TCVD=dev/vda/tce/abc
    TCVD="${TCVD#dev/}"                      # TCVD=vda/tce/abc
    TCVD_DEVICE="${TCVD%%/*}"        # TCVD_DEVICE=vda
    TCVD_LOOPFILE="${TCVD#*/}"        # TCVD_LOOPFILE=vda
    if [ "$TCVD_DEVICE" == "$TCVD_LOOPFILE" ]; then                # yes
        TCVD_DEVICE="$(tc_autoscan $TCVD_LOOPFILE 'f')"         # TCVD_DEVICE="$(tc_autoscan vda 'f')" -> TCVD_DEVICE="" !?
    PARTITION="${TCVD_DEVICE##/dev/}"              # PARTITION=""
    find_mountpoint "$PARTITION"                            # find_mountpoint "" -> MOUNTPOINT=""
    if [ -n "$MOUNTPOINT" ]; then
...
    fi
fi
Stop here now, the problem is with assignment (tc_autoscan vda 'f') to TCVD_DEVICE

[Rich]

Hi nick65go
How to use/share Virtual Disks (Qemu) ?:
http://tinycorelinux.net/faq.html#qemu

[nick65go]

Booting with kernel + initramfs then I have only filesystems in RAM, and no access to any *.qcow2 FROM INSIDE qemu. This is by design, to have access to ONLY what I want from inside qemu, and no undesired links to host files (except self-defined network or file-shares if/when in need) so no stupid program call home to spy, or access personal files -- in theory.

Maybe I need to define myself a new boot case for boot code like "virtio".So the TCVD is for an image (qcow2, img, etc) on a disk FROM where TC booted, in my case from void 

But as you have all my booting parameters in my previous posts, please let me know if you have success with actual (not remastered) tinycore.As I said before, I can remaster with a trimmed down kernel, all virtual devices, one user, a small init script -- to define mount points, variable (language, path, lib-configs, etc) -- in less than 4kb (like toybox). Basically I need a shell and udev. But I am interested to re-discover what is new in tc14 in 2023.All is for fun (and learning -- I forget things the older I get), as there are a lot of ready-made distros to fully "install" in 10 minutes.

[Rich]

Hi nick65go
The  tcvd  boot code is looking for an image file.
Assuming your file containing  /tce  is on  sda1  and is called  qcow2 , try adding this:

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-append tcvd=sda1/qcow2 tce=tcvd restore=tcvd