virtualbox.org

I have linux mint 19 host system with a windows 10 guest. from a fresh boot up on my linux host, the first time I load windows in virtualbox, its fine. But if I shutdown, or save state, then try to boot my guest again (without rebooting my host), it ALWAYS freezes my entire system. The disk activity indicator blinds rapidly and even after 10 minutes nothing happens.

Does the vbox.log log get saved if it freezes on startup?

What can I do and which information can I provide to help solve this? Thank you.

My system has an Intel 6 core, 12 thread CPU. I set the guest to use 6 virtual cpus, which I assume means 3 cores and 6 threads.
VT-x enabled. Nested paging, PAE/nx, and hyper-v paravirtualization.

We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Log in, reboot, let it freeze / Shutdown the VM (force close it if you have to) or reboot your host if it's frozen...
• Right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

I've solved the issue. Apparently, under System > Processor, when it says N cpus, it means physical CPUs, NOT threads. I was assigning 6 CPUs (it showed 12 total but the last 6 were red, leaving me to believe they were reserved threads for the host), so basically, I assigned all the physical cores to the VM which made the host unstable on second boot.

I'm not even sure how the host could run at all after assigning ALL the cores to the guest, could you clarify this?

Either way, the problem has gone away after reducing it to 3 CPUS (cores) for the guest.

GottaGetem wrote:I'm not even sure how the host could run at all after assigning ALL the cores to the guest, could you clarify this?

VirtualBox is like any other (almost) multi-threaded application, but it would be better if we called it multi-core application. Now, the host OS is scheduling multi-tasking apps, they have a scheduler. With this technique, you could run multiple programs in a single CPU. Same idea with multiple CPUs.

I've got a 4 core/8 thread computer. Back a few years, VirtualBox could let me assign up to 12 vCPUs to the guest. Not a happy situation, couldn't even move the mouse, they "fixed" that now...

See also "CPU Cores versus threads" and "Why is it a bad idea to allocate as many VCPUs as there are physical CPUs?".

GottaGetem wrote:I've solved the issue

And that's why I'm marking the thread as [Solved]. Glad you figured it out on your own...