ARM Cortex A53 - Hardware virtualization features

Question

I'm looking at the wikipedia page for the ARM Cortex A53 processor. The feature list for this processor includes the term hardware virtualization. I wanted to ask if anyone knows what feature list does this include ? Its listed separately from Trustzone, so I'm assuming it's indicating features not related to TEE.

Answer 1

ARM knows and describes virtualization features in their books, and the virtualization capability is same for all implementations of ARM version (AVMv8-A, list of implementations). There is book for A53 Cortex MPcore with some details: http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/index.html ARM Cortex-A53 MPCore Processor Technical Reference Manual

4.2.12. AArch64 virtualization registers http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/CIHFBCDH.html

4.3.28. Virtualization Processor ID Register http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/BABEJIHA.html

4.3.29. Virtualization Multiprocessor ID Register http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/BABCBAIE.html

4.3.50. Virtualization Translation Control Register, EL2 http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/CIHJBCCC.html

4.4.27. AArch32 Virtualization registers http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/CIHIFBII.html

4.5.25. Virtualization Processor ID Register http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/BABJDFCE.html

4.5.26. Virtualization Multiprocessor ID Register http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/BABGDAIC.html

4.5.44. Virtualization Translation Control Register http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/CIHBHGJE.html

There are also modes in GIC for interrupt virtualization (http://infocenter.arm.com/help/topic/com.arm.doc.ddi0500g/CIACFDIC.html Chapter 9. Generic Interrupt Controller CPU Interface - of same book) and different address translation schemes for EL2-EL3: ARM Cortex-A Series Programmer’s Guide for ARMv8-A, Memory Management Unit, 12.6. Translations at EL2 and EL3 http://infocenter.arm.com/help/topic/com.arm.doc.den0024a/BABHDAJD.html

There is some data in implementation of ARMv8.1 virtualization support in Linux (https://lwn.net/Articles/650524/), but I'm not sure that A53 core implements v8.1 (it can depend on hardware revision of A53 core). 8.1 version of ARM was declared in december 2014, it includes "Virtualization Host Extensions (VHE)". There are some posts and papers about VHE:

• https://community.arm.com/processors/b/blog/posts/the-armv8-a-architecture-and-its-ongoing-development The ARMv8-A architecture and its ongoing development - 2 Dec 2014 ("early adopter silicon expected in the latter part of 2015", there is also list of changes in 8.1 to 8.0)
• https://www.linaro.org/blog/core-dump/on-the-performance-of-arm-virtualization/ On the Performance of ARM Virtualization, 2016 - basic info about Type 1 (special hypervisor and several normal guest OS) and Type 2 virtualization (one normal OS is host, it can start applications and other VM as guest OS), data on hypercall cost with KVM ARM and Xen ARM vs x86.
• http://docshare01.docshare.tips/files/26002/260020807.pdf KVM/arm64 Architectural Evolutions, 2015. Slides shows how EL3, EL2 and EL1 levels relates to TrustZone (ARMv8-A Privilege Model), lists different variants of virtualization extension in ARM world (Architecture Virtualization Extensions in late ARMv7 with EL2 level; changes by "Virtualization Host Extensions" in v8.1)
• https://www.cs.columbia.edu/~nieh/pubs/isca2016_armvirt.pdf ARM Virtualization: Performance and Architectural Implications, DOI 10.1109/ISCA.2016.35, 2016
• http://events.linuxfoundation.org/sites/events/files/slides/xds15_0.pdf A Few Words on the ARM Ecosystem, 2015