Abstract

Confidential VMs (CVMs) have become the dominant substrate for sensitive cloud workloads, from financial services to privacy-preserving AI inference. The hardware isolation that protects these CVMs from a malicious cloud, however, also blinds their owners to what runs inside them: kernel rootkits planted via network or supply-chain attacks can hide processes, tamper with kernel data structures, and exfiltrate model weights, all under the cover of the same isolation that defends the VM. Cloud tenants therefore need a way to forensically inspect a running CVM from outside, yet every classical approach to doing so collapses under the CVM threat model. Traditional VM introspection (VMI) presupposes a trusted Hypervisor, which CVMs explicitly exclude from the TCB. The state-of-the-art CVM-VMI system, 00SEVen, restores introspection on AMD SEV-SNP by hosting an agent inside the VM at a privileged tier (VMPL0)a mechanism that simply does not exist on Arm CCA, leaving Realm VMs without any introspection solution. We present RealmEye, the first VMI system for Arm CCA Realm VMs. RealmEye places the entire introspection logic inside the Realm Management Monitor (RMM) at R-EL2, achieving hardware-enforced separation between the monitor and the monitored VM: no agent runs inside the Realm, and the Realm itself remains unmodified. From this vantage point, RealmEye reads Realm memory and registers, suspends the VM for consistent snapshots, and traps page-level accesses, all without relying on any interface the in-VM OS exposes. We extend the RMI to carry VMI triggers and encrypted results between the Host and the RMM, bind the result channel to a hardware-attested session with the remote owner, and add a CCA driver backend to LibVMI so that existing tools such as DRAKVUF interoperate with RealmEye unchanged. RealmEye is therefore isolated from the cloud platformincluding a malicious Hypervisorby Arm CCAs own hardware mechanisms, and isolated from in-Realm rootkits by the R-EL2 boundary of the RMM. A periodic, self-driven trigger mode keeps scan timing internal to the RMM, preventing the Hypervisor from colluding with in-Realm rootkits. On the Arm FVP, RealmEye detects both process hiding and syscall-table hooking by Diamorphine, a realworld ARM64 rootkit, and its in-RMM cost is linearly predictable from primitive invocation countslaying the foundation for the first introspection ecosystem on Arm CCA.