Microsoft is responsible for the physical facilities, physical security, infrastructure, and hardware underlying the entire service.
Details on the shared responsibility model employed by Azure VMware Solution can be found in the table below. You can see that a great deal of low-level operational work is handled by the Microsoft leaving the customer to focus on managing their workloads.
Microsoft is responsible for protecting the software and systems that make up the Azure VMware Solution service. This software infrastructure is composed of the compute, storage, and networking software comprising the SDDC, along with the service consoles used to provision Azure VMware Solution.