Virtualisation terminology 101

[bobx001]

is "kvm" (virtualization) turned on in your bios ?

[amiga]

is "kvm" (virtualization) turned on in your bios ?

You appear to be confused with Intel VT-x and VT-d which would be in the firmware (UEFI/legacy BIOS). KVM is a Linux kernel mode that can use virtualization extensions (Intel VT or AMD-V).

https://www.linux-kvm.org/page/Main_Page

Kernel Virtual Machine

KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko.

Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter, etc.

KVM is open source software. The kernel component of KVM is included in mainline Linux, as of 2.6.20. The userspace component of KVM is included in mainline QEMU, as of 1.3.

Also KVM would be used with QEMU and not Virtualbox. If you go a Google search there are many posts/blogs comparing Virtualbox vs QEMU/KVM. You might use VT-x with Virtualbox but not KVM.

[bobx001]

well, if I turn off Virtualzation in my BIOS , then m virtualboxes cannot allocate more than one cpu to the guests, and also I have seen very odd network issues.
turning on virtualization and rebooting fixes all my vbox issues.
go figure, and no, i am not foncusing things.

[amiga]

go figure, and no, i am not foncusing things.

Virtualization support in the BIOS is not the same as Linux KVM. With Intel hardware virtualization support is VT-d.

You are very much confusing Intel VT-d hardware virtualization support and Linux Kernel Virtual Machine which uses underlying virtualization extensions such as VT-d.

Your are turning on VT-d in your BIOS. Your BIOS doesn't know what Linux KVM is as that is at the OS level. Also Virtualbox uses VT-d but not KVM. QEMU uses KVM.

[bobx001]

Also Virtualbox uses VT-d but not KVM. QEMU uses KVM.

Then how come when I turn on Virtualization in my BIOS (with AMD Ryzen CPU), Virtualbox works as expected, and when I turn it off, then it does not work.
Want me to post a video ?

[antikythera]

amiga already explained why above in very simple terms. virtualbox can leverage hardware virtualization but you need it enabled in UEFI to work, otherwise you get software emulated hardware which is not as always stable and certainly not as efficient.

also make sure you are running the latest available build of virtualbox which supports at least the current 4.14 kernels, xorg etc.

[bobx001]

Here, so that you know I am not foncusing anything. (been around computers since 1978, but I don't RTFM, I am a hands on guy, so all these acronyms don't mean jack unless I see them on screen)
SVM ( CPU Virtualization) in the BIOS in my Ryzen PC, is actually "kvm" in the linux kernel, I know so, cuz when I turn it off, linux tells me it has been turned off, reporting it as "kvm".

here you go, instead of a video, some pix.
1. disable "SVM" (kvm) in the bios:


2. we can see that in Virtualbox, adding CPUs feature is disabled, network also works very weird, Host-only will not work right (I suspect more stuff won't work either, like openGL).


3. Re-enabling CPU virtualization:



4. And now we see that Virtualbox works as it should:

[antikythera]

split from the original topic as it isn't helpful to the original poster going off on a complete tangent and hijacking their thread. sometimes it pays to rtfm to use your own parlance bobx001.