Red Hat: CVE-2023-3006: RHEL: Add Spectre-BHB mitigation for AmpereOne (Multiple Advisories)

A known cache speculation vulnerability, known as Branch History Injection (BHI) or Spectre-BHB, becomes actual again for the new hw AmpereOne. Spectre-BHB is similar to Spectre v2, except that malicious code uses the shared branch history (stored in the CPU Branch History Buffer, or BHB) to influence mispredicted branches within the victim's hardware context. Once that occurs, speculation caused by the mispredicted branches can cause cache allocation. This issue leads to obtaining information that should not be accessible.