For some bizarre reason the silly people working at Sony decided to disable the Intel VT extensions by default. But hackers are always smarter than stupid salesmen making decisions in some random department of a Enormous Big Company™: there is a way to re-enable VT extensions.

Big FAT warning: I have only checked this with a Vaio VGN-TZ11MN/N with a Phoenix BIOS version R0052N7. Following the instructions detailed here may render your computer totally unusable, and I decline all responsiblity on the correctness of this method. It worked for me, however.

Fortunately, the code needed to enable the virtualization extensions is still in the BIOS, but there is no menu which allows for easy configuration, so we need to modify the setting using a somewhat “manual” method.

1. Get yourself a bootable DOS system. You can boot from hard-disk, a floppy, a USB flash stick or whatever. I used one of the FreeDOS boot floppy images I used a some time ago to play old computer games in an old Pentium 120 I own. In order to write the image to an USB floppy drive I had to use the following command:

     # dd if=fdosfloppy.img of=/dev/sda

2. Copy a DOS text editor into the bootable device. I used the tiny “T” editor.
3. Get yourself a copy of the symcmos.exe utility and copy it to the bootable device. This tool allows modifying the configuration values stored in the CMOS which by dumping current contents and loading new values from a text file.
4. Boot the DOS system from the device we have prepared so far.
5. Run symcmos -v2 -lsettings.txt, if everything goes as expected now the settings.txt file will contain one setting per line, in a (address)[value] fashion.
6. Scroll down to address 0363 and modify the value from 0000 to 0001. Save the file.
7. Load the new values into the CMOS by running symcmos -v2 -usettings.txt
8. Last, but not least, power down the computer (a warm reboot will not work). If everything went well, now you can boot your favourite GNU/Linux distro, load the kernel module and install KVM:

     # modprobe kvm-intel
     # emerge kvm

For KVM I am using the ebuilds from the sabayon overlay. Also, if there is an error when trying to load the KVM kernel module, maybe you did not follow the procedure correctly: double-check your steps, and remember that using dmesg|tail you can check whether VT is still disabled by the BIOS.

For the intrepidous people trying this, I hope you will have good luck (as I did ), but remember that I can only say that this works for a VGN-TZ11MN/N with a Phoenix BIOS version R0052N7.