[Resolved] CMPXCHG16B issue in v6.0.6

[tech12]

Hi all.

My VMs were all created in v5.1.*. I run Ubuntu Server 18.04, Windows Server 2008, Windows Server R2 2012, Windows 7 Ultimate, Windows 10 Pro and Windows XP.

Since installing v6.0.6 a few days ago, I could not get Server 2012 to work. I received 0x000000c4 errors, and a 'guru meditation' error. Upon research, i executed the command "VBoxManage.exe setextradata global VBoxInternal/CPUM/CMPXCHG16B 1", as listed on the "wintips" website.

This got the Server 2012 instances operational, however the Windows 10 VM would not function. I then entered this, "VBoxManage.exe setextradata "Windows 10" VBoxInternal/CPUM/CMPXCHG16B" & "VBoxManage.exe setextradata "VM Name" VBoxInternal/CPUM/CMPXCHG16B 0" into command prompt, and Windows 10 now operates correctly.

Can anyone shed any light on why this happens on the new version of Virtualbox? I didn't have to change any settings with previous versions of Virtualbox.

To confirm, BIOS settings are correct, and host & clients are all updated to the latest versions & updates.

Many thanks

Euan

[mpack]

Since installing v6.0.6 a few days ago, I could not get Server 2012 to work. I received 0x000000c4 errors, and a 'guru meditation' error. Upon research, i executed the command "VBoxManage.exe setextradata global VBoxInternal/CPUM/CMPXCHG16B 1", as listed on the "wintips" website.

Why do you consider "Wintips" an authority on VirtualBox?

What does the current user manual say?

To install or run Win2k12, just select the Win2k12 template. Nothing else is necessary.

If you need to continue this discussion then please post a VM log file. With the VM fully shut down, right click and "Show Log" in the GUI, save "VBox.log" (no other file) to a zip, and attach the zip here.

[tech12]

Hi mpack,

I wasn't trying to do an install, only run the previously operational VMs from the v5.2 version of Virtualbox. Absolutely no settings were changed in Machine settings and the VMs were already using the Server 2012 / Windows 10 templates.

Log files attached.

Thanks

[mpack]

00:00:01.042263 Guest OS type: 'Windows7_64'

Your Win2K12 VM is using the Win7 template, not the 2K12 template. The requirements of Win8 (which 2k12 is basically a version of) are very different from Win7.

I don't see any error reported in the Win10 log, however I do see that the VM seems to have been suspended and resumed several times. I hope that the VBoxManage settings changes were made while the VM was fully shut down, and not when suspended. Most OS's' will probably not react well to having major features of the motherboard change while the OS is asleep.

I also notice that both of your VMs have allocated 100% of the hosts available cores to the VM - leaving nothing for host programs (including VirtualBox itself). Obviously not good. This has been discussed many times on the forum already, I suggest that you search for it. The RAM allocation also seems rather conservative given how much the host has available.

[tech12]

Thanks for your replies.

I have altered the templates as suggested. The settings must have got accidentally changed as I recently installed Hyper-v and converted my Virtualbox VMs to try on that platform. Finding no real performance or, for my needs, practical improvements, i uninstalled Hyper-v and returned to my platform of choice, Virtualbox.

I have also disabled the CMPXCHG16B instruction I implemented, and all VMs are running as normal. I have also increased the ram to 4gb and changed all VMs to 2 cores, and find this to be perfectly adequate for my needs, thanks for the suggestion.

Again, thank you for your help and thanks to Oracle/developers for producing an amazing platform. My production VMs run 24/7 and have never skipped a beat. I hope more people use Virtualbox in critical / production use. I for one can vouch for it's reliability and ease of use.

Best regards

[socratis]

and all VMs are running as normal

Glad you got it going, and thank you for the feedback! Marking as [Resolved].