AMD SEV
AMD Secure Encrypted Virtualization. EPYC-only (2017+). Encrypts VM memory using AES-128 with a key managed by the AMD Secure Processor. Hypervisor cannot read guest memory. Foundation for confidential-cloud VMs.
Three generations: SEV (2017), SEV-ES (Encrypted State, 2020), SEV-SNP (Secure Nested Paging, 2021). SNP adds integrity protection + attestation. Use cases: untrusted-cloud VMs, multi-tenant hypervisor where mutual distrust. Google Cloud Confidential VMs use SEV. Azure DCasv5 also. Performance overhead: 2-5% under typical VM workloads. Distinct from Intel SGX: SGX is per-process-enclave, SEV is per-VM isolation. Modern position: confidential-computing segment dominated by SEV-SNP, Intel TDX is the response.