Re: [RFC PATCH qemu] spapr/docs: Add a few words about x-vof

[Daniel Henrique Barboza]

On 5/6/22 02:51, Alexey Kardashevskiy wrote:
> The alternative small firmware needs a few words of what it can and
> absolutely cannot do; this adds those words.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>   docs/system/ppc/pseries.rst | 28 ++++++++++++++++++++++++++++
>   1 file changed, 28 insertions(+)
>
> diff --git a/docs/system/ppc/pseries.rst b/docs/system/ppc/pseries.rst
> index d9b65ad4e850..4c98a94f9add 100644
> --- a/docs/system/ppc/pseries.rst
> +++ b/docs/system/ppc/pseries.rst
> @@ -32,14 +32,42 @@ Missing devices
>   Firmware
>   ========
>   
> +The pSeries platform in QEMU comes with 2 firmwares:
> +
>   `SLOF <https://github.com/aik/SLOF>`_ (Slimline Open Firmware) is an
>   implementation of the `IEEE 1275-1994, Standard for Boot (Initialization
>   Configuration) Firmware: Core Requirements and Practices
>   <https://standards.ieee.org/standard/1275-1994.html>`_.
>   
> +SLOF performs bus scanning, PCI resource allocation, provides the client
> +interface to boot from block devices and network.
> +
>   QEMU includes a prebuilt image of SLOF which is updated when a more recent
>   version is required.
>   
> +VOF (Virtual Open Firmware) is a minimalistic firmware to work with
> +``-machine pseries,x-vof=on``. When enabled, the firmware acts as a slim
> +shim and QEMU implements parts of the IEEE 1275 Open Firmware interface.
> +
> +VOF does not have device drivers, does not do PCI resource allocation and
> +relies on ``-kernel`` used with Linux kernels recent enough (v5.4+)
> +to PCI resource assignment. It is ideal to use with petitboot.
> +
> +Booting via ``-kernel`` supports the following:
> ++-------------------+-------------------+------------------+
> +| kernel            | pseries,x-vof=off | pseries,x-vof=on |
> ++===================+===================+==================+
> +| vmlinux BE        |     ✓             |     ✓            |
> ++-------------------+-------------------+------------------+
> +| vmlinux LE        |     ✓             |     ✓            |
> ++-------------------+-------------------+------------------+
> +| zImage.pseries BE |     x             |     ✓¹           |
> ++-------------------+-------------------+------------------+
> +| zImage.pseries LE |     ✓             |     ✓            |
> ++-------------------+-------------------+------------------+

You need an empty line at the start and at the end of the table. Otherwise it'll
be rendered as regular text.

> +Notes:

I also don't believe you need the "Notes:" addendum here. It's clear that you're
making an observation about the zImage.pseries BE and x-vof=on case.


Everything else LGTM. If no one else has any comment, and you're ok with these
changes I mentioned, I can amend it myself with my R-b.



Thanks,


Daniel


> +¹ must set kernel-addr=0
> +
>   Build directions
>   ================
>