hw/ppc/spapr: Add the "rtas-version" property to /rtas

LoPAR requires every property listed in its table of /rtas device tree
properties to be present before the OS is booted (R1-7.2.6-3 and Table
7.4 in LoPAR 2.9; the same requirement is in LoPAPR 1.1). One of them
is "rtas-version", an integer encoding of the RTAS interface version,
and LoPAR says it describes version 1 of that interface.

spapr_dt_rtas() sets "rtas-size", "rtas-error-log-max" and
"rtas-event-scan-rate" but never "rtas-version", so a client that reads
it finds no RTAS: NetBSD's RTAS driver fails to attach when the
property is absent.

Set it to 1, the version LoPAR describes.

Signed-off-by: Showta Ishizaki <zakinko@snowrabbit.org>
---
 hw/ppc/spapr.c         | 1 +
 include/hw/ppc/spapr.h | 3 +++
 2 files changed, 4 insertions(+)

Hi Amit,

I am sorry for the slow reply.  I have just started a new job, and it
took me a while to get back to this work.

Thank you for the review, for checking it against PAPR v10.60, and for
testing it on a nestedv2 KVM guest.  Both of your suggestions make
sense; v2 below cites PAPR v10.60 first, keeps LoPAR and LoPAPR as
secondary references, and the comment on RTAS_VERSION now names PAPR
v10.60 Table 20.  There is no other change to the code.

Thanks,
Showta

-- >8 --
Subject: [PATCH v2] hw/ppc/spapr: Add the "rtas-version" property to /rtas

PAPR requires every property listed in its table of /rtas device tree
properties to be present before the OS is booted (R-7.2.6-3 and Table
20 in PAPR v10.60; the same requirement is in LoPAR 2.9 and LoPAPR
1.1). One of them is "rtas-version", an integer encoding of the RTAS
interface version, and PAPR says it describes version 1 of that
interface.

spapr_dt_rtas() sets "rtas-size", "rtas-error-log-max" and
"rtas-event-scan-rate" but never "rtas-version", so a client that reads
it finds no RTAS: NetBSD's RTAS driver fails to attach when the
property is absent.

Set it to 1, the version PAPR describes.

Signed-off-by: Showta Ishizaki <zakinko@snowrabbit.org>
---
v2:
- Cite PAPR v10.60 first, as the rest of the spapr code does, and keep
  LoPAR and LoPAPR as secondary references.
- The comment on RTAS_VERSION now names PAPR v10.60 Table 20.

 hw/ppc/spapr.c         | 1 +
 include/hw/ppc/spapr.h | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 6d99464486..8a1b5b37b6 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1068,6 +1068,7 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
                           RTAS_ERROR_LOG_MAX));
     _FDT(fdt_setprop_cell(fdt, rtas, "rtas-event-scan-rate",
                           RTAS_EVENT_SCAN_RATE));
+    _FDT(fdt_setprop_cell(fdt, rtas, "rtas-version", RTAS_VERSION));
 
     g_assert(msi_nonbroken);
     _FDT(fdt_setprop(fdt, rtas, "ibm,change-msix-capable", NULL, 0));
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 9acda15d4f..b92d25c18e 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -830,6 +830,9 @@ void spapr_load_rtas(SpaprMachineState *spapr, void *fdt, hwaddr addr);
 
 #define RTAS_EVENT_SCAN_RATE    1
 
+/* The RTAS interface version PAPR v10.60 Table 20 describes */
+#define RTAS_VERSION            1
+
 /* This helper should be used to encode interrupt specifiers when the related
  * "interrupt-controller" node has its "#interrupt-cells" property set to 2 (ie,
  * VIO devices, RTAS event sources and PHBs).

Hi Showta,

Thanks for addressing the nits — both look good.  A few things before this is
ready:

1. Please send v2 as a proper standalone patch submission (not inline in a
   reply), so it gets picked up correctly by patchwork.

2. Since the nits have been addressed, please carry over the tags in v2:

Reviewed-by: Amit Machhiwal amachhiw@linux.ibm.com
Tested-by: Amit Machhiwal amachhiw@linux.ibm.com

3. One minor nit - see below:

On 2026/10/04 08:42 AM, 蟹澤翔太 wrote:
> Hi Amit,
> 
> I am sorry for the slow reply.  I have just started a new job, and it
> took me a while to get back to this work.
> 
> Thank you for the review, for checking it against PAPR v10.60, and for
> testing it on a nestedv2 KVM guest.  Both of your suggestions make
> sense; v2 below cites PAPR v10.60 first, keeps LoPAR and LoPAPR as
> secondary references, and the comment on RTAS_VERSION now names PAPR
> v10.60 Table 20.  There is no other change to the code.
> 
> Thanks,
> Showta
> 
> -- >8 --
> 
> Subject: [PATCH v2] hw/ppc/spapr: Add the "rtas-version" property to /rtas
> PAPR requires every property listed in its table of /rtas device tree
> properties to be present before the OS is booted (R-7.2.6-3 and Table
> 20 in PAPR v10.60; the same requirement is in LoPAR 2.9 and LoPAPR
> 1.1). One of them is "rtas-version", an integer encoding of the RTAS
> interface version, and PAPR says it describes version 1 of that
> interface.
> 
> spapr_dt_rtas() sets "rtas-size", "rtas-error-log-max" and
> "rtas-event-scan-rate" but never "rtas-version", so a client that reads
> it finds no RTAS: NetBSD's RTAS driver fails to attach when the
> property is absent.
> 
> Set it to 1, the version PAPR describes.
> 
> Signed-off-by: Showta Ishizaki <zakinko@snowrabbit.org>
> ---
> v2:
> - Cite PAPR v10.60 first, as the rest of the spapr code does, and keep
>   LoPAR and LoPAPR as secondary references.
> - The comment on RTAS_VERSION now names PAPR v10.60 Table 20.
> 
>  hw/ppc/spapr.c         | 1 +
>  include/hw/ppc/spapr.h | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 6d99464486..8a1b5b37b6 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1068,6 +1068,7 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
>                            RTAS_ERROR_LOG_MAX));
>      _FDT(fdt_setprop_cell(fdt, rtas, "rtas-event-scan-rate",
>                            RTAS_EVENT_SCAN_RATE));
> +    _FDT(fdt_setprop_cell(fdt, rtas, "rtas-version", RTAS_VERSION));
>  
>      g_assert(msi_nonbroken);
>      _FDT(fdt_setprop(fdt, rtas, "ibm,change-msix-capable", NULL, 0));
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 9acda15d4f..b92d25c18e 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -830,6 +830,9 @@ void spapr_load_rtas(SpaprMachineState *spapr, void *fdt, hwaddr addr);
>  
>  #define RTAS_EVENT_SCAN_RATE    1
>  
> +/* The RTAS interface version PAPR v10.60 Table 20 describes */

The wording reads a bit awkwardly. How about:

/* RTAS interface version, as defined by PAPR v10.60 Table 20 */

Thanks,
Amit

On 2026/10/05 02:53 PM, Amit Machhiwal wrote:
> Hi Showta,
> 
> Thanks for addressing the nits — both look good.  A few things before this is
> ready:
> 
> 1. Please send v2 as a proper standalone patch submission (not inline in a
>    reply), so it gets picked up correctly by patchwork.
> 
> 2. Since the nits have been addressed, please carry over the tags in v2:
> 
> Reviewed-by: Amit Machhiwal amachhiw@linux.ibm.com
> Tested-by: Amit Machhiwal amachhiw@linux.ibm.com

Correction, the tags should read:

Reviewed-by: Amit Machhiwal <amachhiw@linux.ibm.com>
Tested-by: Amit Machhiwal <amachhiw@linux.ibm.com>

Thanks,
Amit