> If they are running on Hyper-V on Azure, there is no underlying kernel doing anything.
In a Xen model as I understand it, the dom0 kernel is still actually responsible for talking to all the hardware directly and presenting a virtualized implementation that Xen can mux other guests on, no? So there’s still a kernel there and it’s doing quite a bit of work, no?
The dom0 kernel is responsible for talking to devices such as a disk or a NIC, yes, be that Linux, NT, *BSD, etc. The hypervisor is typically responsible for enforcing isolation of compute, memory, etc. The line does blur - for example Hyper-V may be configured with something called the “root scheduler” with which NT is responsible for scheduling virtual CPUs [0] - though the hypervisor is still enforcing the isolation.
> If they are running on Hyper-V on Azure, there is no underlying kernel doing anything.
In a Xen model as I understand it, the dom0 kernel is still actually responsible for talking to all the hardware directly and presenting a virtualized implementation that Xen can mux other guests on, no? So there’s still a kernel there and it’s doing quite a bit of work, no?