[Bug]: New KVM Backends not working with many older CPU (KVM_CAP_KVM_CAP_XCRS) #603
Description
Version
trunk/main
Host OS Type
Linux
Host OS name + version
Debian Buster 10 or newer (with custom build Kernel 6.18)
Host Architecture
x86
Guest OS Type
Linux
Guest Architecture
x86
Guest OS name + version
All types of guest (Does not apply)
Component
VMM
What happened?
I tested the latest test build supporting the new KVM implementation. But with Intel Core 2 Duo Quad Q9300 2.5Ghz, I get this error when launching the Guest: KVM_CAP_KVM_CAP_XCRS
I know this CPU doesn't support Nested paging. It should still work without it because the main Virtualbox VMM Backend is able to launch any Guest with this CPU. I can see the problem being from Cyberus technology (cyberus-technology/virtualbox-kvm#4). Many newer processors seem to have this problem because they are not 2nd generation CPU... That is non-sense because we should be able to just disable this feature and the VM will still work (like QEMU, VMWare, firecracker, etc). I ask Oracle to find a solution to make the KVM implementation work without the XSAVE CPU feature.
I was hoping to find a solution for all kind of BSOD with the actual/main VMM implementation (see #387). But now, this "requirement" for KVM blocks me from using it...
How can we reproduce this?
Have an Intel CPU without XSAVE/XCRS feature and start a VM. Here's a log file with the KVM features supported for my CPU.
VBOX_MISSING_KVM_CAPABILITY_LOG.txt
Did you upload all of your necessary log files, screenshots, etc.?
- Yes, I've uploaded all pertinent files to this issue.