MSI machines support just a single method for updating the firmware, and that is through .exe files released by MSI.
Since MSI officially supports just the Windows operating system, all there support and services are centred around it.
Is there any known procedure for updating the firmware on an MSI machine running Linux (esp. Ubuntu)?
I don't think trying to run the updated firmware .exe file through Wine or PlayOnLinux would be a safe thing to do!
Can it be done through a virtual machine running on my Ubuntu?
This website says that you load firmware onto a USB stick and then reboot.
https://www.gamersnexus.net/guides/2772-how-to-update-bios-with-m-flash-msi-motherboards
Quoting them...
Setup & Necessary Tools
Motherboard with simple firmware flashing tools USB storage device The most recent version of the motherboard’s BIOS, found on the motherboard vendor’s website. Place this onto the USB key.
Step-by-Step Guide to Updating BIOS on an MSI Motherboard
It’s very easy, really: