Re: [PATCH v3 08/10] docs/system/riscv: document initial virt RPMI support

On 7/14/2026 4:56 AM, Subrahmanya Lingappa wrote:
> Document the opt-in virt RPMI transport and the initial HSM, system
> reset, and system suspend service groups.
> 
> Signed-off-by: Subrahmanya Lingappa <[email protected]>
> ---

Reviewed-by: Daniel Henrique Barboza <[email protected]>

>   docs/system/riscv/virt.rst | 65 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 65 insertions(+)
> 
> diff --git a/docs/system/riscv/virt.rst b/docs/system/riscv/virt.rst
> index 60850970ce..31cd945a3b 100644
> --- a/docs/system/riscv/virt.rst
> +++ b/docs/system/riscv/virt.rst
> @@ -146,6 +146,71 @@ The following machine-specific options are supported:
>   
>     Enables the riscv-iommu-sys platform device. Defaults to 'off'.
>   
> +- rpmi=[on|off]
> +
> +  Enables the RISC-V RPMI shared-memory transport. This option defaults to
> +  "off", is TCG-only, and is available only when QEMU is built with librpmi
> +  support. This support targets the RISC-V Platform Management Interface
> +  (RPMI) Specification v1.0 Ratified (`RPMI v1.0 specification`_). The initial
> +  ``virt`` implementation exposes RPMI system reset, system suspend, and HSM
> +  service groups. System reset can request shutdown or cold reboot through
> +  RPMI. HSM uses the ``virt`` hart IDs and supports hart discovery, status,
> +  start, stop, and suspend commands. System suspend uses QEMU's suspend and
> +  wakeup path. Migration is currently blocked while RPMI transport and service
> +  VMState support is being designed.
> +
> +  The build dependency is provided by `librpmi`_. QEMU requires librpmi 1.0.0
> +  or newer. If the host distribution does not provide a librpmi development
> +  package, build and install it from the upstream source tree so that
> +  ``pkg-config`` can find ``librpmi.pc``:
> +
> +  .. code-block:: bash
> +
> +    $ git clone https://github.com/riscv-software-src/librpmi.git
> +    $ cd librpmi
> +    $ make
> +    $ make install I=/usr/local
> +    $ export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:$PKG_CONFIG_PATH
> +    $ pkg-config --modversion librpmi
> +
> +  The librpmi repository can also generate installable ``librpmi-dev`` Debian
> +  packages with ``make deb-pkg`` and ``librpmi-devel`` RPM packages with
> +  ``make rpm-pkg``. After installing librpmi, configure QEMU with
> +  ``--enable-librpmi`` or ``-Dlibrpmi=enabled``.
> +
> +.. _RPMI v1.0 specification: https://github.com/riscv-non-isa/riscv-rpmi/releases/download/v1.0/riscv-rpmi.pdf
> +.. _librpmi: https://github.com/riscv-software-src/librpmi
> +
> +RPMI firmware and guest smoke
> +-----------------------------
> +
> +A firmware-level RPMI smoke test can be run with OpenSBI, a Linux kernel, and a
> +RISC-V disk image:
> +
> +.. code-block:: bash
> +
> +  $ qemu-system-riscv64 \
> +      -machine virt,rpmi=on \
> +      -cpu rv64 -smp 4 -m 4G -nographic \
> +      -bios /path/to/fw_jump.bin \
> +      -kernel /path/to/Image \
> +      -append "root=/dev/vda rw console=ttyS0 earlycon=sbi" \
> +      -drive file=/path/to/rootfs.img,format=raw,if=virtio,snapshot=on
> +
> +The OpenSBI banner should report RPMI-backed HSM and system suspend support.
> +After the guest reaches a shell, normal guest reboot/poweroff commands exercise
> +the RPMI system reset path.
> +
> +RPMI device tree policy
> +-----------------------
> +
> +RPMI is currently described through FDT only; no ACPI representation is emitted
> +for the RPMI transport or service groups. The ``virt`` machine uses the
> +``riscv,rpmi-shmem-mbox`` shared-memory mailbox node plus child service nodes
> +with ``riscv,rpmi-*`` compatible strings. These binding names are part of the
> +RPMI RFC surface and may be revised if the RISC-V RPMI bindings change during
> +review.
> +
>   Running Linux kernel
>   --------------------
>