Immediate crash (guru meditation) with nested virtualization

[bcandler]

The physical host is a Macbook Pro Retina 13" Early 2015, with Broadwell i7-5557U and 16GB RAM, running macOS 10.14.6 (security update 2021-002)

The main VM is Ubuntu 18.04.5 with 4GB of RAM. I have enabled nested virtualization for this VM from the VBox CLI:

VBoxManage modifyvm "vtptest" --nested-hw-virt on

(this is because the nested virt button in the GUI was disabled, see #19245, even though this processor supports it)

With VBox 6.1.18, I get an instant crash on starting a nested VM. The attached files were triggered by running the following command inside the main VM:

/usr/bin/qemu-system-x86_64 -enable-kvm -nographic

[bcandler]

console dump (note: this was before the crash, which was done over an ssh session)

[bcandler]

qemu version inside VM:

nsrc@vtptest:~$ dpkg-query -l | grep qemu
ii  ipxe-qemu                              1.0.0+git-20180124.fbe8c52d-0ubuntu2.2          all          PXE boot firmware - ROM images for qemu
ii  ipxe-qemu-256k-compat-efi-roms         1.0.0+git-20150424.a25a16d-0ubuntu2             all          PXE boot firmware - Compat EFI ROM images for qemu
ii  qemu-block-extra:amd64                 1:2.11+dfsg-1ubuntu7.35                         amd64        extra block backend modules for qemu-system and qemu-utils
ii  qemu-kvm                               1:2.11+dfsg-1ubuntu7.35                         amd64        QEMU Full virtualization on x86 hardware
ii  qemu-system-common                     1:2.11+dfsg-1ubuntu7.35                         amd64        QEMU full system emulation binaries (common files)
ii  qemu-system-x86                        1:2.11+dfsg-1ubuntu7.35                         amd64        QEMU full system emulation binaries (x86)
ii  qemu-utils                             1:2.11+dfsg-1ubuntu7.35                         amd64        QEMU utilities

[aeichner]

Please try the latest 6.1 testbuild from here. It should fix the issue.

[Tcharl]

I confirm the latest testbuild have fixed the issue: I had the same behaviour on a Mac Big Sur host, running a VB guest on fedora 33, running itself a KVM guest on F33.

Everything VB was crashing on 6.18, and everything is fine with the latest test build.

Thank you Devs, keep being awesome!

[sorenisanerd]

I'm experiencing the same problem, but due to corporate security restrictions, I can't install the test builds. Is there an ETA on a new release?

[aeichner]

The latest release should have the fix incorporated, closing.