Linux Landing Kernel Workaround For AMD TLBI Erratum #1718

AMD TLBI Erratum #1718 was worked around in CPU microcode for addressing a defect in certain Zen CPUs where the Translation Lookaside Buffer Invalidate Instruction use could lead to to stale translation entries. But for those on affected AMD CPUs and not running the updated microcode, a kernel workaround is being introduced with today's Linux 7.3-rc7 kernel and to be back-ported to prior kernel versions...