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AMD SME

Architecture referenceFeex

AMD Secure Memory Encryption, SME, dey give memory-encryption facility dem wey di platform and operating system dey manage. E different from per-VM SEV protection, and e no dey establish confidential-computing deployment by itself.

Wetin you need know

AMD Secure Memory Encryption, SME, dey give memory-encryption facility dem wey di platform and operating system dey manage. E different from per-VM SEV protection, and e no dey establish confidential-computing deployment by itself.

How e dey work

Di memory-encryption architecture dey identify encrypted mapping dem through defined address-bit mechanism and platform control dem. Di OS must calculate di encryption bit and any effect wey e get on available physical address bit dem, and manage shared or device-visible memory according to di platform rule dem.

Where e dey useful

OS fit arrange for correct memory page dem to encrypt as data dey travel go external memory. DMA buffer dem and oda shared mapping dem need compatible treatment, so to just turn on one bit alone no be complete deployment procedure.

How to check support and enablement

Use di AMD memory-encryption CPUID information and exact platform firmware/OS documentation to know whether e support and dey enabled. Check di active encryption policy and device compatibility. Keep vendor recovery guide safe before you change firmware memory-encryption setting dem.

Capability, enablement and enforcement na different ting dem wey person must check separately. Processor fit support protection while di OS, application or virtual-machine policy no turn am on. Database support field no be attestation say running system dey secure.

Wetin di feature no dey guarantee

SME no mean per-guest isolation, memory integrity, SEV-SNP or protection against every attack from privileged software. Person no suppose assume say transparent platform encryption policy dem and OS-managed SME configuration dem be di same ting just from summary field.

Compatibility and performance inside real life

Keep di OS, firmware and affected runtime current. If protection show compatibility problem, make you use vendor diagnostics and supported update dem first. Broad protection toggle fit affect oda application dem wey no concern am, so e suppose follow clear deployment and recovery policy.

Practical verification checklist

  1. Record di exact processor or platform model plus di application, OS and runtime version dem wey dey involve. Make you keep di exact word dem wey di error or requirement use.
  2. Check di manufacturer reference for dat exact model, den inspect di real capability and enabled state inside di environment where di program dey run.
  3. Compare every single requirement of di binary or backend wey you choose. Name wey resemble am, alias, or broad technology label no reach.
  4. Confirm say di application select di implementation wey dem intend. Use di diagnostics wey dem document and supported fallback if requirement dem no complete.
  5. Make only one supported change at a time, den run di same workload again. Keep di original configuration and recovery way ready.

If dem list di feature but software no fit use am

Start from di exact component wey dey fail. Hardware database dey describe capability wey dem record; di operating system or hypervisor fit show different real environment. If illegal-instruction error happen, you still need to check di exact instruction wey cause di fault and di binary build, because corrupt file or anoda instruction wey no dey supported fit give di same kind problem.

Install di application, driver or runtime version wey get support for dat exact platform, and use di vendor documented baseline or fallback build if e need am. Software update no fit create instruction wey di processor no get. Firmware and security-policy change dem suppose follow di system manufacturer procedure and recovery plan, no be just any common optimization advice.

Sources and scope of dis explanation

AMD Secure Encrypted Virtualization developer resources · Linux kernel: AMD memory encryption · AMD64 Architecture Programmer's Manual, Volume 2: System Programming

Dis reference dem establish architectural behavior and software requirement dem. Dem no dey independently verify every feature value for any linked hardware model page. For model support, use dat page manufacturer evidence and check di active system configuration. Dis article no supply benchmark, certification or independent review date.

Sources and verification

Editorial ownership: Feex. No independent review date dey recorded. How we dey do research.

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