Xen project Mailing List

Experiment n. 2 :

Below I have applied the zImage patch of Julien to the Elliott Mitchell code :

https://xenbits.xen.org/gitweb/?p=people/julieng/freebsd.git;a=commit;h=12a7cb346b88c6d3f52a20b98f361dc62797fbcd

and I've used the kernel generated by the Elliott MItchell code :

root@marietto:/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen # ./start-freebsd

xencall: error: Could not obtain handle on privileged command interface /dev/xen/privcmd: No such file or directory

libxl: error: libxl.c:102:libxl_ctx_alloc: cannot open libxc handle: No such file or directory

cannot init xl context

xencall: error: Could not obtain handle on privileged command interface /dev/xen/privcmd: No such file or directory

libxl: error: libxl.c:102:libxl_ctx_alloc: cannot open libxc handle: No such file or directory

cannot init xl context

Here I have used the kernel.bin :

# ./start-freebsd

xencall: error: Could not obtain handle on privileged command interface /dev/xen/privcmd: No such file or directory
libxl: error: libxl.c:102:libxl_ctx_alloc: cannot open libxc handle: No such file or directory
cannot init xl context
xencall: error: Could not obtain handle on privileged command interface /dev/xen/privcmd: No such file or directory
libxl: error: libxl.c:102:libxl_ctx_alloc: cannot open libxc handle: No such file or directory
cannot init xl context

(same error)

Anyway I think that I made some progress...

This is the freebsd.cfg file :

kernel="/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel.bin"
memory=64
name="freebsd"
vcpus=1
autoballon="off"
#disk=[ 'phy:/dev/loop0,xvda,w' ]
disk=[ 'phy:/dev/md0s2a,xvda,w' ]

And this is the start-freebsd.sh script that I've used :

mdconfig -a -t vnode -f FreeBSD-13.2-RELEASE-armv7.img -u 0
xl create freebsd.cfg
xl console freebsd

On Mon, Dec 11, 2023 at 7:41 PM Chuck Zmudzinski <brchuckz@xxxxxxxxxxxx> wrote:

On 12/11/2023 12:59 PM, Mario Marietto wrote:
> root@marietto:/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel # file /mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel/kernel
>
> ELF 32-bit LSB executable,ARM, EABI5 version 1 (FreeBSD), dynamically linked, interpreter /red/herring, BuildID[sha1]=5e6982c9cb67d9c94571b76419142a8c495388d0, for FreeBSD 13.2, not stripped
>
> root@marietto:/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel # file /mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel/kernel.bin
>
> kernel.bin: data

This needs to be :

kernel.bin: Linux kernel ARM boot executable zImage (little-endian)

>
> It does not boot from the kernel.bin file.

I suggest not trying to direct boot a kernel in Xen on arm unless the file command reports the kernel image is a Linux kernel ARM boot executable zImage (little endian).

Did you try applying Julien's patch (link is in my earlier message) to add zImage support to FreeBSD? Maybe after applying the patch the kernel.bin file will be in the correct zImage format.

The patch I linked in the earlier

>
>
> On Mon, Dec 11, 2023 at 6:23 PM Chuck Zmudzinski <brchuckz@xxxxxxxxxxxx <mailto:brchuckz@xxxxxxxxxxxx>> wrote:
>
> On 12/11/2023 9:02 AM, Mario Marietto wrote:
> > Hello.
> >
> > Finally I tried to recompile the FreeBSD kernel using the @Elliott Mitchell <mailto:ehem+freebsd@xxxxxxx <mailto:ehem%2Bfreebsd@xxxxxxx>> code because I want to boot FreeBSD as domU with Xen installed on my Arm 32 bit Chromebook. Unfortunately it didn't work at all. Maybe I've missed something / I haven't understood well what to do. Please give me some suggestions.
> >
> > Basically this is what I did :
> >
> > $ created a vm called FreeBSD-13.2-RELEASE-armv7.img with qemu / kvm / libvirt / virt-manager
> >
> > $ within the vm : mkdir /build-xen
> >
> > $ cd /usr
> >
> > $ git clone https://gitlab.com/ehem/freebsd-src.git
> >
> > $ cd freebsd-src
> >
> > $ make KERNCONF=GENERIC TARGET=arm TARGET_ARCH=armv7 buildkernel
> >
> > $ make KERNCONF=GENERIC TARGET=arm TARGET_ARCH=armv7 DESTDIR=/build-xen installkernel
> >
> > $ echo "/dev/xbd0 / ufs rw 1 1" > /mnt/etc/fstab
> >
> > $ nano /etc/ttys (add the line 'xc0 "/usr/libexec/getty Pc" xterm on secure")
> >
> > $ renamed the directories dtb to dtb_ and kernel to kernel_ that are inside the /boot dir of the vm
> >
> > $ copied the directory dtb and kernel from the directory /build-xen to the directory /boot inside the vm
> >
> > $ shut down the vm
> >
> > $ copied the directory /build-xen outside of the vm using this method (in this case I used Linux installed on the Host OS,because the kernel that I'm using on the Chromebook has the kernel parameter related to the ufs2 fs set to off) :
> >
> > on my X64 workstation :
> >
> > # modprobe ufs
> >
> > # sudo losetup -fP FreeBSD-13.2-RELEASE-armv7.img
> >
> > # ls /dev/loop0*
> >
> > /dev/loop0 /dev/loop0p1 /dev/loop0p2 /dev/loop0p5
> >
> > # mount -t ufs -o ufstype=ufs2 /dev/loop0p5 ./FreeBSD-xen
> >
> > then :
> >
> > # nano freebsd.cfg
> >
> > kernel="/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel/kernel"
> > memory=64
> > name="freebsd"
> > vcpus=1
> > autoballon="off"
> > disk=[ 'phy:/dev/loop0,xvda,w' ]
> > # nano start-freebsd
> > losetup -fP FreeBSD-13.2-RELEASE-armv7.img
> > xl create freebsd.cfg
> > xl console freebsd
> >
> > # ./start-freebsd
> >
> > Parsing config from freebsd.cfg
> > xc: error: panic: xg_dom_elfloader.c:63: xc_dom_guest_type: image not capable of booting inside a HV
> > M container: Invalid kernel
>
> It is detecting the kernel as an elf binary. IIUC, Xen on arm guests should have zImage kernels, not elf.
>
> > libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image failed
> > libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain 1:cannot (re-)build domain: -3
> > libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 1:Non-existent domain
> > libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 1:Unable to destroy guest
> > libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 1:Destruction of domain failed
> > freebsd is an invalid domain identifier (rc=-6)
> >
> > I have also tried with kernel.bin :
> >
> > # nano freebsd.cfg
> >
> > kernel="/mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel/kernel.bin"
> > memory=64
> > name="freebsd"
> > vcpus=1
> > autoballon="off"
> > disk=[ 'phy:/dev/loop0,xvda,w' ]
> >
> > # ./start-freebsd
> >
> > Parsing config from freebsd.cfg
> > xc: error: panic: xg_dom_core.c:689: xc_dom_find_loader: no loader found: Invalid kernel
> > libxl: error: libxl_dom.c:571:libxl__build_dom: xc_dom_parse_image failed
> > libxl: error: libxl_create.c:1640:domcreate_rebuild_done: Domain 2:cannot (re-)build domain: -3
> > libxl: error: libxl_domain.c:1183:libxl__destroy_domid: Domain 2:Non-existent domain
> > libxl: error: libxl_domain.c:1137:domain_destroy_callback: Domain 2:Unable to destroy guest
> > libxl: error: libxl_domain.c:1064:domain_destroy_cb: Domain 2:Destruction of domain failed
> > freebsd is an invalid domain identifier (rc=-6)
> >
> > --
> > Mario.
>
> I would be interested to see the output of :
>
> $ file /mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel/kernel
>
> and
>
> $ file /mnt/zroot2/zroot2/OS/Chromebook/domU/freebsd-xen/boot-xen/kernel/kernel.bin
>
> I have been trying out Julien's old patch set from 2014, and in there was this patch :
>
> > arm: Add zImage support
> >
> > Currently Xen on ARM is only supported zImage for guest kernel. Adding support
> > for ARM ELF in the toolstack looks a bit complicate for ARM (though there is
> > an x86 support).
>
> Link to Julien's 2014 patch to provide zImage support for FreeBSD :
>
> https://xenbits.xen.org/gitweb/?p=people/julieng/freebsd.git;a=commit;h=12a7cb346b88c6d3f52a20b98f361dc62797fbcd <https://xenbits.xen.org/gitweb/?p=people/julieng/freebsd.git;a=commit;h=12a7cb346b88c6d3f52a20b98f361dc62797fbcd>
>
> When using Julien's patches, from 'file' I find that the kernel file is in
> the elf format, and the kernel.bin file is in the zImage format, so I have
> been trying to boot the kernel.bin file.
>
>
>
> --
> Mario.

Re: xc_dom_guest_type: image not capable of booting inside a HV M container: Invalid kernel