If you run systemctl reboot on a non-vm it will actually power cycle the system and cause it to go back through the BIOS and then the bootloader. Using systemctl kexec allows you to “restart” the computer without having to go all the way back through the full boot process.
In the case of a VM, some are setup to do this behind the scenes. For example, virt-manager allows for direct kernel booting. If you look in the options there will be a path to the kernel. If its not setup that way, then the VM still has a bootloader. In that case, restarting the VM with kexec will allow for a faster reboot since the bootloader is skipped completely.
If you run systemctl reboot on a non-vm it will actually power cycle the system and cause it to go back through the BIOS and then the bootloader. Using systemctl kexec allows you to “restart” the computer without having to go all the way back through the full boot process.
In the case of a VM, some are setup to do this behind the scenes. For example, virt-manager allows for direct kernel booting. If you look in the options there will be a path to the kernel. If its not setup that way, then the VM still has a bootloader. In that case, restarting the VM with kexec will allow for a faster reboot since the bootloader is skipped completely.