[PATCH] Documentation: RISC-V: Define Xlinuxs{s,m}aia

[Palmer Dabbelt]

The AIA specification was only partially frozen, but provides no way to
refer to the subset of behavior that has been frozen.  It seems like
there's not a whole lot of interest in the non-frozen behavior, so let's
just define an extension that only consists of the frozen behavior

Signed-off-by: Palmer Dabbelt <palmer at rivosinc.com>
---
 Documentation/riscv/extensions.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 Documentation/riscv/extensions.rst

diff --git a/Documentation/riscv/extensions.rst b/Documentation/riscv/extensions.rst
new file mode 100644
index 000000000000..c12bd3780520
--- /dev/null
+++ b/Documentation/riscv/extensions.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Custom RISC-V Extensions
+========================
+
+* The `Xlinuxsmaia` and `Xlinuxssaia` extensions coorespond to the standard
+  `Smaia` and `Ssaia` extensions as defined by version 1.0-RC2 of the RISC-V
+  Advanced Interrupt Architecture (AIA) specification, with the difference that
+  chapters 5 (Duo-PLIC) and 9 (IOMMU Support for MSIs to Virtual Machines) do
+  not exist.
-- 
2.39.0