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-rw-r--r--docs/system/arm/cpu-features.rst23
-rw-r--r--docs/system/arm/emulation.rst1
-rw-r--r--docs/system/arm/sbsa.rst14
3 files changed, 38 insertions, 0 deletions
diff --git a/docs/system/arm/cpu-features.rst b/docs/system/arm/cpu-features.rst
index f4524b6d3e..6bb88a40c7 100644
--- a/docs/system/arm/cpu-features.rst
+++ b/docs/system/arm/cpu-features.rst
@@ -435,3 +435,26 @@ As with ``sve-default-vector-length``, if the default length is larger
 than the maximum vector length enabled, the actual vector length will
 be reduced.  If this property is set to ``-1`` then the default vector
 length is set to the maximum possible length.
+
+RME CPU Properties
+==================
+
+The status of RME support with QEMU is experimental.  At this time we
+only support RME within the CPU proper, not within the SMMU or GIC.
+The feature is enabled by the CPU property ``x-rme``, with the ``x-``
+prefix present as a reminder of the experimental status, and defaults off.
+
+The method for enabling RME will change in some future QEMU release
+without notice or backward compatibility.
+
+RME Level 0 GPT Size Property
+-----------------------------
+
+To aid firmware developers in testing different possible CPU
+configurations, ``x-l0gptsz=S`` may be used to specify the value
+to encode into ``GPCCR_EL3.L0GPTSZ``, a read-only field that
+specifies the size of the Level 0 Granule Protection Table.
+Legal values for ``S`` are 30, 34, 36, and 39; the default is 30.
+
+As with ``x-rme``, the ``x-l0gptsz`` property may be renamed or
+removed in some future QEMU release.
diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index ecbbd63adf..bdafc68819 100644
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -66,6 +66,7 @@ the following architecture extensions:
 - FEAT_RAS (Reliability, availability, and serviceability)
 - FEAT_RASv1p1 (RAS Extension v1.1)
 - FEAT_RDM (Advanced SIMD rounding double multiply accumulate instructions)
+- FEAT_RME (Realm Management Extension) (NB: support status in QEMU is experimental)
 - FEAT_RNG (Random number generator)
 - FEAT_S2FWB (Stage 2 forced Write-Back)
 - FEAT_SB (Speculation Barrier)
diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
index f571fe645e..a8e0b530a2 100644
--- a/docs/system/arm/sbsa.rst
+++ b/docs/system/arm/sbsa.rst
@@ -46,6 +46,9 @@ to be a complete compliant DT. It currently reports:
    - platform version
    - GIC addresses
 
+Platform version
+''''''''''''''''
+
 The platform version is only for informing platform firmware about
 what kind of ``sbsa-ref`` board it is running on. It is neither
 a QEMU versioned machine type nor a reflection of the level of the
@@ -54,3 +57,14 @@ SBSA/SystemReady SR support provided.
 The ``machine-version-major`` value is updated when changes breaking
 fw compatibility are introduced. The ``machine-version-minor`` value
 is updated when features are added that don't break fw compatibility.
+
+Platform version changes:
+
+0.0
+  Devicetree holds information about CPUs, memory and platform version.
+
+0.1
+  GIC information is present in devicetree.
+
+0.2
+  GIC ITS information is present in devicetree.