It works fine for me - you probably failed to add it to the secure boot.
It appears that every new kernel has a new signature - try it with secure boot disabled.

proof it works:
user@LLR4:~> uname -a
Linux LLR4 6.3.6-1-default #1 SMP PREEMPT_DYNAMIC Mon Jun 5 07:58:35 UTC 2023 (f583ba4) x86_64 x86_64 x86_64 GNU/Linux
user@LLR4:~> psg virtual
user 3829 1 0 Jun09 ? 00:07:06 /usr/lib/virtualbox/VBoxXPCOMIPCD
user 3835 1 0 Jun09 ? 00:32:28 /usr/lib/virtualbox/VBoxSVC --auto-shutdown
user 3861 3807 0 Jun09 pts/7 00:02:48 /usr/lib/virtualbox/VirtualBox6 %U
user 6375 3835 3 06:52 ? 00:04:04 /usr/lib/virtualbox/VirtualBoxVM --comment suse15 --startvm 7e154200-c32c-40ac-a01d-1b7632c55598 --no-startvm-errormsgbox
user 14879 3835 4 Jun11 ? 00:40:16 /usr/lib/virtualbox/VirtualBoxVM --comment Ubuntu --startvm d5db27f0-e3b3-4e18-84a2-2d999edf7504 --no-startvm-errormsgbox
user 19499 3835 4 Jun10 ? 02:21:53 /usr/lib/virtualbox/VirtualBoxVM --comment Manjaro --startvm 1222f84b-36a0-4b58-b84a-526d7a225af5 --no-startvm-errormsgbox
user 20149 3835 3 Jun10 ? 01:38:42 /usr/lib/virtualbox/VirtualBoxVM --comment tumbleweed --startvm 4713d533-f86c-463c-8da8-ee67427a1fed --no-startvm-errormsgbox
user 20424 3835 15 Jun10 ? 07:35:26 /usr/lib/virtualbox/VirtualBoxVM --comment win11 --startvm ce4f8eb9-4894-4373-89fb-dbc625899167 --no-startvm-errormsgbox
user 20748 3835 16 Jun10 ? 08:12:45 /usr/lib/virtualbox/VirtualBoxVM --comment win10 --startvm b791d51d-ccab-4e90-bef1-2bfa508394d8 --no-startvm-errormsgbox
user 21318 3835 4 Jun10 ? 02:17:31 /usr/lib/virtualbox/VirtualBoxVM --comment twkde --startvm 25ebb4a2-a3af-4a44-a3da-88fc2adf06dc --no-startvm-errormsgbox
user 21381 3835 0 Jun10 ? 00:00:02 /usr/lib/virtualbox/VBoxNetDHCP --comment Gnome --config /home/user/.config/VirtualBox/Gnome-Dhcpd.config --log /home/user/.config/VirtualBox/Gnome-Dhcpd.log
user 21382 3835 0 Jun10 ? 00:00:28 /usr/lib/virtualbox/VBoxNetNAT --network Gnome
user 21600 3835 6 Jun10 ? 03:14:30 /usr/lib/virtualbox/VirtualBoxVM --comment fedora --startvm d6da2ee7-920b-413f-8f9c-f944c8a6fa76 --no-startvm-errormsgbox
user 21878 3835 4 Jun10 ? 02:07:58 /usr/lib/virtualbox/VirtualBoxVM --comment gnome --startvm 04aa4c99-1973-469c-8c57-8d44d2628ca6 --no-startvm-errormsgbox
user 27600 3835 3 Jun11 ? 00:34:32 /usr/lib/virtualbox/VirtualBoxVM --comment Mint --startvm da7f2283-4722-4d94-890a-93c03e4b8178 --no-startvm-errormsgbox
user@LLR4:~>

After booting kernel 6.3.6-1, run the command 'sudo dmesg > dmesg.txt', and attach file dmesg.txt to this bug report.

Created attachment 867526 [details]
dmesg after restart of Kernel 6.3.6-1-default

(In reply to Larry Rainey from comment #1)
> It works fine for me - you probably failed to add it to the secure boot.
> It appears that every new kernel has a new signature - try it with secure
> boot disabled.

In VirtualBox Manager, for the machine Settings, System tab, Enable Secure Boot is unchecked, and Enable EFI is checked.

Thanks

The vbox kernel modules loaded OK. I'm not sure what is causing the problem. Did you try to start a VM during the time covered by that dmesg output?

Is this a rev 11+ CPU? What does 'hwinfo --cpu' show for any one of the CPUs? If it is, then you may be hit by the ibt  problem. Follow the instructions in https://forums.opensuse.org/t/virtualbox-fails-to-start-on-newest-cpus-with-6-3-6-kernel-how-to-fix-until-oracle-finds-a-fix/166879 for a workaround.

If this does not resolve your problem, what symptoms are you seeing for kernel 6.3.6?

(In reply to Larry Finger from comment #5)
> The vbox kernel modules loaded OK. I'm not sure what is causing the problem.
> Did you try to start a VM during the time covered by that dmesg output?

The dmesg was taken immediately after a fresh boot (although following a hard reboot after VirtualBox froze the screen).

> Is this a rev 11+ CPU? What does 'hwinfo --cpu' show for any one of the
> CPUs? If it is, then you may be hit by the ibt  problem. Follow the
> instructions in
> https://forums.opensuse.org/t/virtualbox-fails-to-start-on-newest-cpus-with-
> 6-3-6-kernel-how-to-fix-until-oracle-finds-a-fix/166879 for a workaround.

localhost:~ # hwinfo --cpu
01: None 00.0: 10103 CPU                                        
  [Created at cpu.462]
  Unique ID: rdCR.j8NaKXDZtZ6
  Hardware Class: cpu
  Arch: X86-64
  Vendor: "GenuineIntel"
  Model: 6.183.1 "13th Gen Intel(R) Core(TM) i9-13900HX"
  Features: fpu,vme,de,pse,tsc,msr,pae,mce,cx8,apic,sep,mtrr,pge,mca,cmov,pat,pse36,clflush,dts,acpi,mmx,fxsr,sse,sse2,ss,ht,tm,pbe,syscall,nx,pdpe1gb,rdtscp,lm,constant_tsc,art,arch_perfmon,pebs,bts,rep_good,nopl,xtopology,nonstop_tsc,cpuid,aperfmperf,tsc_known_freq,pni,pclmulqdq,dtes64,monitor,ds_cpl,vmx,est,tm2,ssse3,sdbg,fma,cx16,xtpr,pdcm,sse4_1,sse4_2,x2apic,movbe,popcnt,tsc_deadline_timer,aes,xsave,avx,f16c,rdrand,lahf_lm,abm,3dnowprefetch,cpuid_fault,epb,ssbd,ibrs,ibpb,stibp,ibrs_enhanced,tpr_shadow,vnmi,flexpriority,ept,vpid,ept_ad,fsgsbase,tsc_adjust,bmi1,avx2,smep,bmi2,erms,invpcid,rdseed,adx,smap,clflushopt,clwb,intel_pt,sha_ni,xsaveopt,xsavec,xgetbv1,xsaves,split_lock_detect,avx_vnni,dtherm,arat,pln,pts,hwp,hwp_notify,hwp_act_window,hwp_epp,hwp_pkg_req,hfi,umip,pku,ospke,waitpkg,gfni,vaes,vpclmulqdq,rdpid,movdiri,movdir64b,fsrm,md_clear,serialize,arch_lbr,ibt,flush_l1d,arch_capabilities
  Clock: 1800 MHz
  BogoMips: 4838.40
  Cache: 36864 kb
  Units/Processor: 128
  Config Status: cfg=no, avail=yes, need=no, active=unknown

> If this does not resolve your problem, what symptoms are you seeing for
> kernel 6.3.6?

VirtualBox starts the manager fine, once the VM launch sequence is started the computer screen freezes and only a manual shutdown using the power button is possible

I will investigate the ibt fix, however its strange that the previous kernel has no issues in launching a VM ... so it initially seems more like a kernel issue than a cpu-issue

> > Is this a rev 11+ CPU? What does 'hwinfo --cpu' show for any one of the
> > CPUs? If it is, then you may be hit by the ibt  problem. Follow the
> > instructions in
> > https://forums.opensuse.org/t/virtualbox-fails-to-start-on-newest-cpus-with-
> > 6-3-6-kernel-how-to-fix-until-oracle-finds-a-fix/166879 for a workaround.

The ibt workaround fixed my issue ... thanks!

Thanks ... this is resolved with the new ibt workaround

The reason it happens with kernel 6.3.6 and not with 6.3.4 is that openSUSE turned on kernel hardening with the newer kernels. For those of us with older CPUs, it did not make any difference.

I am reopening this bug entry until Oracle comes up with the fix. The IBT "feature" in the CPU changes the way that virtualization works, and as the fix has not yet been found by Oracle with their relatively large group of CPU experts, I am not even going to try.

*** Bug 1212191 has been marked as a duplicate of this bug. ***

*** Bug 1212690 has been marked as a duplicate of this bug. ***

Fixed with VB 7.0.10.

This is an autogenerated message for OBS integration:
This bug (1212209) was mentioned in
https://build.opensuse.org/request/show/1099933 15.5 / virtualbox
https://build.opensuse.org/request/show/1099934 15.4 / virtualbox

openSUSE-RU-2023:0194-1: An update that has two recommended fixes can now be installed.

Category: recommended (important)
Bug References: 1212209,1212761
CVE References: 
JIRA References: 
Sources used:
openSUSE Leap 15.4 (src):    virtualbox-7.0.10-lp154.2.35.1, virtualbox-kmp-7.0.10-lp154.2.35.1

(In reply to Marcus Meissner from comment #14)
> openSUSE-RU-2023:0194-1: An update that has two recommended fixes can now be
> installed.
> 
> Category: recommended (important)
> Bug References: 1212209,1212761
> CVE References: 
> JIRA References: 
> Sources used:
> openSUSE Leap 15.4 (src):    virtualbox-7.0.10-lp154.2.35.1,
> virtualbox-kmp-7.0.10-lp154.2.35.1

Marcus ... I get a different failure now on Tumbleweed 6.4.4-1-default (64-bit) with VirtualBox 7.0.10-1.1 ... the VM launch progress bar starts and then aborts ... this is without ibt=off ...

openSUSE-SU-2023:0213-1: An update that contains security fixes can now be installed.

Category: security (important)
Bug References: 1209727,1211941,1212209,1212761
CVE References: 
JIRA References: 
Sources used:
openSUSE Leap 15.5 (src):    virtualbox-7.0.10-lp155.2.5.1, virtualbox-kmp-7.0.10-lp155.2.5.1

Markus ... I'm not sure what I'm missing here ... for me the virtual box instance of Windows fails immediately after the progress bar ... whether I use or don't use ibt=off ... am I awaiting a new virtual box in the Suse repos?
At the moment my system is:
13th Gen Intel® Core™ i9-13900HX, Tumbleweed 6.4.8-1-default (64-bit), KDE 5.27.7, Wayland and VirtualBox 7.0.10-1.1-x86 from OpenSuse (and openSuse-Tumbleweed-Oss has the same version)

If windows start to load and the tpm 2.0  is selected and corrupt it will stop loading.
remove tpm 2.0 from the settings and see if windows loads.

(In reply to Larry Rainey from comment #18)
> If windows start to load and the tpm 2.0  is selected and corrupt it will
> stop loading.
> remove tpm 2.0 from the settings and see if windows loads.

Setting tpm to none has fixed the issue ... many thanks Larry