Re: [Qemu-arm] [PATCH v9 5/5] fw_cfg: document ACPI device node information

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Feb 19, 2016 at 01:20:29PM -0500, Gabriel L. Somlo wrote:
> Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> Reviewed-by: Marc Marí <markmb@redhat.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  docs/specs/fw_cfg.txt | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt
> index 2099ad9..5414140 100644
> --- a/docs/specs/fw_cfg.txt
> +++ b/docs/specs/fw_cfg.txt
> @@ -84,6 +84,15 @@ Selector Register address: Base + 8 (2 bytes)
>  Data Register address:     Base + 0 (8 bytes)
>  DMA Address address:       Base + 16 (8 bytes)
>  
> +== ACPI Interface ==
> +
> +The fw_cfg device is defined with ACPI ID "QEMU0002". Since we expect
> +ACPI tables to be passed into the guest through the fw_cfg device itself,
> +the guest-side firmware can not use ACPI to find fw_cfg. However, once the
> +firmware is finished setting up ACPI tables and hands control over to the
> +guest kernel, the latter can use the fw_cfg ACPI node for a more accurate
> +inventory of in-use IOport or MMIO regions.
> +
>  == Firmware Configuration Items ==
>  
>  === Signature (Key 0x0000, FW_CFG_SIGNATURE) ===
> -- 
> 2.4.3