Error: piix4_smbus 0000:00:07.3: SMBus Host controller not enabled!

Running Linux (in my case Kali on VMware, kernel 4.18.0-kali2-amd64) and seeing this at startup?

piix4_smbus 0000:00:07.3: SMBus Host controller not enabled!

Why it happens

The kernel loads the i2c_piix4 driver to talk to the motherboard's SMBus (a small management bus used for things like temperature sensors). Inside a virtual machine, that controller isn't really there — the hypervisor only partially emulates it — so the driver loads, finds nothing usable, and prints this complaint. It's harmless and cosmetic: nothing is broken, it just clutters your boot log. The clean fix is to tell the kernel not to load that module at all.

The fix

Edit the first blacklist file:

sudo nano /etc/modprobe.d/blacklist-libnfc.conf

and add these 3 lines at the end of the file:

blacklist i2c_piix4
blacklist i2c-piix4
blacklist intel_powerclamp

Do the same with these other two files:

sudo nano /etc/modprobe.d/amd64-microcode-blacklist.conf

sudo nano /etc/modprobe.d/intel-microcode-blacklist.conf

Then update the initramfs image so the blacklist is applied early at boot:

sudo update-initramfs -u -k all

then reboot your computer.

Confirm it worked

After rebooting, check the kernel log — this should now come back empty:

sudo dmesg | grep -i piix4

No output means the message is gone for good.