Faulty instructions in Alibaba's T-Head C910 RISC-V CPUs blow away all security

Researchers at CISPA discovered multiple architectural vulnerabilities in T-Head (Alibaba) RISC-V cores — most critically GhostWrite on the C910 — which lets unprivileged native code directly read/write physical memory and gain kernel/machine-level control; the issue is caused by a faulty non-standard vector extension implementation and requires disabling the vector extension (with major performance and compatibility impacts) as the primary mitigation.