BibTeX for a paper by David Kotz at Dartmouth College. For more information about this paper, visit this web page: https://www.cs.dartmouth.edu/~kotz/research/abdollahi-caec-poster/index.html @Misc{abdollahi:caec-poster, author = {Sina Abdollahi and Amir {Al Sadi} and David Kotz and Marios Kogias and Hamed Haddadi}, title = {{Poster: Confidential, Attestable, and Efficient Inter-CVM Communication with Arm CCA}}, howpublished = {European Conference on Computer Systems (EuroSys)}, year = 2026, month = {April}, publisher = {ACM}, copyright = {the authors}, URL = {https://www.cs.dartmouth.edu/~kotz/research/abdollahi-caec-poster/index.html}, abstract = {Confidential Virtual Machines (CVMs) are increasingly adopted to protect sensitive workloads from privileged adversaries such as the hypervisor. While they provide strong isolation guarantees, existing CVM architectures lack first-class mechanisms for inter-CVM data sharing due to their disjoint memory model. Under this model, a CVM's accessible memory is either shared with the hypervisor or protected from both the hypervisor and all other CVMs. This design simplifies reasoning about memory ownership; however, it fundamentally precludes plaintext data sharing between CVMs because all inter-CVM communication must pass through hypervisor-accessible memory, requiring costly encryption and decryption to preserve confidentiality and integrity. \par In this paper, we introduce CAEC, a system that enables protected memory sharing between CVMs. CAEC builds on Arm Confidential Compute Architecture (CCA) and extends its firmware to support Confidential Shared Memory (CSM), a memory region securely shared between multiple CVMs while remaining inaccessible to the hypervisor and all non-participating CVMs. CAECs design is fully compatible with CCA hardware and introduces only a modest increase (4\%) in CCA firmware code size.}, }