Slightly supprised they're patching it via a "BIOS update" rather than a microcode update... unless it is, and UEFI is just the now prefered method of pushing it.
Where else would the microcode update happen? After the OS boots?
Yeah, looks like Windows has it too. Strange. I loathe the idea that you need a "supported OS" to get a fix for your CPU that should work as intended. :)