AMD CPUs -- Guest Memory Vulnerabilities

AMD reports:

Researchers from IOActive have reported that it may be possible for an attacker with ring 0 access to modify the configuration of System Management Mode (SMM) even when SMM Lock is enabled. Improper validation in a model specific register (MSR) could allow a malicious program with ring0 access to modify SMM configuration while SMI lock is enabled, potentially leading to arbitrary code execution.

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