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: 0e236d3 ("ppc/spapr: Implement FWNMI System Reset delivery") Signed-off-by: Alexey Kardashevskiy <[email protected]> Message-Id: <[email protected]> Reviewed-by: Greg Kurz <[email protected]> Signed-off-by: David Gibson <[email protected]>
dreddy · Jul 9, 2021 · 7381c5d · 7381c5d
1 parent 642f6f5
commit 7381c5d
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git 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
@@ -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 */