The performing of virtual machine (VM)-based secure operations is enabled using a trusted co-processor that is able to operate in a secure mode to perform operations in a multi-tenant environment that are protected from other VMs and DOM-0, among other domains and components. A customer VM can contact a VM manager (VMM) to perform an operation with respect to sensitive data. The VMM can trigger secure mode operation, whereby memory pages are marked and access blocked to entities outside a trusted enclave. The trusted co-processer can measure the VMM and compare the result against an earlier result to ensure that the VMM has not been compromised. Once the operations are performed, the trusted co-processor can return the results, and the VMM can exit the secure mode such that access to the marked pages and customer data is restored.