docs/system/arm: Document which architecture extensions we emulate

These days the Arm architecture has a wide range of fine-grained
optional extra architectural features. We implement quite a lot
of these but by no means all of them. Document what we do implement,
so that users can find out without having to dig through back-issues
of our Changelog on the wiki.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20210617140328.28622-1-peter.maydell@linaro.org
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Peter Maydell 2021-06-17 15:03:28 +01:00
parent 15613357ba
commit 741292face
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A-profile CPU architecture support
==================================
QEMU's TCG emulation includes support for the Armv5, Armv6, Armv7 and
Armv8 versions of the A-profile architecture. It also has support for
the following architecture extensions:
- FEAT_AA32BF16 (AArch32 BFloat16 instructions)
- FEAT_AA32HPD (AArch32 hierarchical permission disables)
- FEAT_AA32I8MM (AArch32 Int8 matrix multiplication instructions)
- FEAT_AES (AESD and AESE instructions)
- FEAT_BF16 (AArch64 BFloat16 instructions)
- FEAT_BTI (Branch Target Identification)
- FEAT_DIT (Data Independent Timing instructions)
- FEAT_DPB (DC CVAP instruction)
- FEAT_DotProd (Advanced SIMD dot product instructions)
- FEAT_FCMA (Floating-point complex number instructions)
- FEAT_FHM (Floating-point half-precision multiplication instructions)
- FEAT_FP16 (Half-precision floating-point data processing)
- FEAT_FRINTTS (Floating-point to integer instructions)
- FEAT_FlagM (Flag manipulation instructions v2)
- FEAT_FlagM2 (Enhancements to flag manipulation instructions)
- FEAT_HPDS (Hierarchical permission disables)
- FEAT_I8MM (AArch64 Int8 matrix multiplication instructions)
- FEAT_JSCVT (JavaScript conversion instructions)
- FEAT_LOR (Limited ordering regions)
- FEAT_LRCPC (Load-acquire RCpc instructions)
- FEAT_LRCPC2 (Load-acquire RCpc instructions v2)
- FEAT_LSE (Large System Extensions)
- FEAT_MTE (Memory Tagging Extension)
- FEAT_MTE2 (Memory Tagging Extension)
- FEAT_PAN (Privileged access never)
- FEAT_PAN2 (AT S1E1R and AT S1E1W instruction variants affected by PSTATE.PAN)
- FEAT_PAuth (Pointer authentication)
- FEAT_PMULL (PMULL, PMULL2 instructions)
- FEAT_PMUv3p1 (PMU Extensions v3.1)
- FEAT_PMUv3p4 (PMU Extensions v3.4)
- FEAT_RDM (Advanced SIMD rounding double multiply accumulate instructions)
- FEAT_RNG (Random number generator)
- FEAT_SB (Speculation Barrier)
- FEAT_SEL2 (Secure EL2)
- FEAT_SHA1 (SHA1 instructions)
- FEAT_SHA256 (SHA256 instructions)
- FEAT_SHA3 (Advanced SIMD SHA3 instructions)
- FEAT_SHA512 (Advanced SIMD SHA512 instructions)
- FEAT_SM3 (Advanced SIMD SM3 instructions)
- FEAT_SM4 (Advanced SIMD SM4 instructions)
- FEAT_SPECRES (Speculation restriction instructions)
- FEAT_SSBS (Speculative Store Bypass Safe)
- FEAT_TLBIOS (TLB invalidate instructions in Outer Shareable domain)
- FEAT_TLBIRANGE (TLB invalidate range instructions)
- FEAT_TTCNP (Translation table Common not private translations)
- FEAT_TTST (Small translation tables)
- FEAT_UAO (Unprivileged Access Override control)
- FEAT_VHE (Virtualization Host Extensions)
- FEAT_VMID16 (16-bit VMID)
- FEAT_XNX (Translation table stage 2 Unprivileged Execute-never)
- SVE (The Scalable Vector Extension)
- SVE2 (The Scalable Vector Extension v2)
For information on the specifics of these extensions, please refer
to the `Armv8-A Arm Architecture Reference Manual
<https://developer.arm.com/documentation/ddi0487/latest>`_.
When a specific named CPU is being emulated, only those features which
are present in hardware for that CPU are emulated. (If a feature is
not in the list above then it is not supported, even if the real
hardware should have it.) The ``max`` CPU enables all features.
R-profile CPU architecture support
==================================
QEMU's TCG emulation support for R-profile CPUs is currently limited.
We emulate only the Cortex-R5 and Cortex-R5F CPUs.
M-profile CPU architecture support
==================================
QEMU's TCG emulation includes support for Armv6-M, Armv7-M, Armv8-M, and
Armv8.1-M versions of the M-profile architucture. It also has support
for the following architecture extensions:
- FP (Floating-point Extension)
- FPCXT (FPCXT access instructions)
- HP (Half-precision floating-point instructions)
- LOB (Low Overhead loops and Branch future)
- M (Main Extension)
- MPU (Memory Protection Unit Extension)
- PXN (Privileged Execute Never)
- RAS (Reliability, Serviceability and Availability): "minimum RAS Extension" only
- S (Security Extension)
- ST (System Timer Extension)
For information on the specifics of these extensions, please refer
to the `Armv8-M Arm Architecture Reference Manual
<https://developer.arm.com/documentation/ddi0553/latest>`_.
When a specific named CPU is being emulated, only those features which
are present in hardware for that CPU are emulated. (If a feature is
not in the list above then it is not supported, even if the real
hardware should have it.) There is no equivalent of the ``max`` CPU for
M-profile.

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@ -99,6 +99,12 @@ undocumented; you can get a complete list by running
arm/virt
arm/xlnx-versal-virt
Emulated CPU architecture support
=================================
.. toctree::
arm/emulation
Arm CPU features
================