[PULL 03/33] spapr: tune rtas-size

From: David Gibson <david@gibson.dropbear.id.au>
To: peter.maydell@linaro.org, groug@kaod.org
Cc: aik@ozlabs.ru, qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
	David Gibson <david@gibson.dropbear.id.au>
Subject: [PULL 03/33] spapr: tune rtas-size
Date: Fri,  9 Jul 2021 15:16:58 +1000	[thread overview]
Message-ID: <20210709051728.170203-4-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20210709051728.170203-1-david@gibson.dropbear.id.au>

From: Alexey Kardashevskiy <aik@ozlabs.ru>

QEMU reserves space for RTAS via /rtas/rtas-size which tells the client
how much space the RTAS requires to work which includes the RTAS binary
blob implementing RTAS runtime. Because pseries supports FWNMI which
requires plenty of space, QEMU reserves more than 2KB which is
enough for the RTAS blob as it is just 20 bytes (under QEMU).

Since FWNMI reset delivery was added, RTAS_SIZE macro is not used anymore.
This replaces RTAS_SIZE with RTAS_MIN_SIZE and uses it in
the /rtas/rtas-size calculation to account for the RTAS blob.

Fixes: 0e236d347790 ("ppc/spapr: Implement FWNMI System Reset delivery")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20210622070336.1463250-1-aik@ozlabs.ru>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr.c         | 8 ++++++--
 include/hw/ppc/spapr.h | 2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 4dd90b75cc..9e19c57032 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -919,9 +919,13 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void *fdt)
      *
      * The extra 8 bytes is required because Linux's FWNMI error log check
      * is off-by-one.
+     *
+     * RTAS_MIN_SIZE is required for the RTAS blob itself.
      */
-    _FDT(fdt_setprop_cell(fdt, rtas, "rtas-size", RTAS_ERROR_LOG_MAX +
-			  ms->smp.max_cpus * sizeof(uint64_t)*2 + sizeof(uint64_t)));
+    _FDT(fdt_setprop_cell(fdt, rtas, "rtas-size", RTAS_MIN_SIZE +
+                          RTAS_ERROR_LOG_MAX +
+                          ms->smp.max_cpus * sizeof(uint64_t) * 2 +
+                          sizeof(uint64_t)));
     _FDT(fdt_setprop_cell(fdt, rtas, "rtas-error-log-max",
                           RTAS_ERROR_LOG_MAX));
     _FDT(fdt_setprop_cell(fdt, rtas, "rtas-event-scan-rate",
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index f05219f75e..5697327e4c 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -770,7 +770,7 @@ void spapr_load_rtas(SpaprMachineState *spapr, void *fdt, hwaddr addr);
 #define SPAPR_IS_PCI_LIOBN(liobn)   (!!((liobn) & 0x80000000))
 #define SPAPR_PCI_DMA_WINDOW_NUM(liobn) ((liobn) & 0xff)
 
-#define RTAS_SIZE               2048
+#define RTAS_MIN_SIZE           20 /* hv_rtas_size in SLOF */
 #define RTAS_ERROR_LOG_MAX      2048
 
 /* Offset from rtas-base where error log is placed */
-- 
2.31.1


