spapr: tune rtas-size

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>

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 4dd90b75cc5285d60995a5b8b79502a46a0a5deb..9e19c570327e4191288e4dbf1df940e073e6db97 100644 (file)
--- 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 f05219f75ef6c9757d33c7bb92160ca2d3fcab79..5697327e4c004c1133839e86d1117df9b978d24b 100644 (file)
--- 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 */