AMD’s Secure Memory Encryption is a feature provided to EPYC and Ryzen Pro series processors, allowing the processor to encrypt memory at the hardware level. AMD said that this feature has no significant impact on performance and is suitable for any operating system and application. Because it is hardware accelerated, it will not rely on software.
Although it seems to have many benefits, the secure memory encryption function has an error in the interaction with the IOMMU and graphics driver in the Linux driver, which causes the Linux
system host to fail to start. The affected system also does not recognize encrypted memory, especially because some devices do not have the correct direct memory access API or firmware to support SMU. This error mainly occurs on the APU code-named Raven Ridge, other Ryzen series processors may also encounter. Of course, this problem will not affect users of Windows systems.