[Qemu-arm] [PATCH v2 04/11] hw/arm/aspeed: add a 'execute-in-place' property to boot directly from CE0

[Cédric Le Goater]

The overhead for the OpenBMC firmware images using the a custom U-Boot
is around 2 seconds, which is fine, but with a U-Boot from mainline,
it takes an extra 50 seconds or so to reach Linux. A quick survey on
the number of reads performed on the flash memory region gives the
following figures :

  OpenBMC U-Boot      922478 (~ 3.5 MBytes)
  Mainline U-Boot   20569977 (~ 80  MBytes)

QEMU must be trashing the TCG TBs and reloading text very often. Some
addresses are read more than 250.000 times. Until we find a solution
to improve boot time, execution from MMIO is not activated by default.

Setting this option also breaks migration compatibility.

Signed-off-by: Cédric Le Goater <address@hidden>
---
 include/hw/arm/aspeed.h |  2 ++
 hw/arm/aspeed.c         | 44 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/include/hw/arm/aspeed.h b/include/hw/arm/aspeed.h
index 325c091d09e4..b67f633ddbd1 100644
--- a/include/hw/arm/aspeed.h
+++ b/include/hw/arm/aspeed.h
@@ -30,6 +30,8 @@ typedef struct AspeedBoardConfig {
 
 typedef struct AspeedMachine {
     MachineState parent_obj;
+
+    bool mmio_exec;
 } AspeedMachine;
 
 #define ASPEED_MACHINE_CLASS(klass) \
diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
index 6b33ecd5aa43..e7b87e355f12 100644
--- a/hw/arm/aspeed.c
+++ b/hw/arm/aspeed.c
@@ -216,11 +216,18 @@ static void aspeed_board_init(MachineState *machine,
          * SoC and 128MB for the AST2500 SoC, which is twice as big as
          * needed by the flash modules of the Aspeed machines.
          */
-        memory_region_init_rom(boot_rom, OBJECT(bmc), "aspeed.boot_rom",
-                               fl->size, &error_abort);
-        memory_region_add_subregion(get_system_memory(), FIRMWARE_ADDR,
-                                    boot_rom);
-        write_boot_rom(drive0, FIRMWARE_ADDR, fl->size, &error_abort);
+        if (ASPEED_MACHINE(machine)->mmio_exec) {
+            memory_region_init_alias(boot_rom, OBJECT(bmc), "aspeed.boot_rom",
+                                     &fl->mmio, 0, fl->size);
+            memory_region_add_subregion(get_system_memory(), FIRMWARE_ADDR,
+                                        boot_rom);
+        } else {
+            memory_region_init_rom(boot_rom, OBJECT(bmc), "aspeed.boot_rom",
+                                   fl->size, &error_abort);
+            memory_region_add_subregion(get_system_memory(), FIRMWARE_ADDR,
+                                        boot_rom);
+            write_boot_rom(drive0, FIRMWARE_ADDR, fl->size, &error_abort);
+        }
     }
 
     aspeed_board_binfo.kernel_filename = machine->kernel_filename;
@@ -313,6 +320,30 @@ static void aspeed_machine_init(MachineState *machine)
     aspeed_board_init(machine, amc->board);
 }
 
+static bool aspeed_get_mmio_exec(Object *obj, Error **errp)
+{
+    return ASPEED_MACHINE(obj)->mmio_exec;
+}
+
+static void aspeed_set_mmio_exec(Object *obj, bool value, Error **errp)
+{
+    ASPEED_MACHINE(obj)->mmio_exec = value;
+}
+
+static void aspeed_machine_instance_init(Object *obj)
+{
+    ASPEED_MACHINE(obj)->mmio_exec = false;
+}
+
+static void aspeed_machine_class_props_init(ObjectClass *oc)
+{
+    object_class_property_add_bool(oc, "execute-in-place",
+                                   aspeed_get_mmio_exec,
+                                   aspeed_set_mmio_exec, &error_abort);
+    object_class_property_set_description(oc, "execute-in-place",
+                           "boot directly from CE0 flash device", 
&error_abort);
+}
+
 static void aspeed_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
@@ -327,6 +358,8 @@ static void aspeed_machine_class_init(ObjectClass *oc, void 
*data)
     mc->no_cdrom = 1;
     mc->no_parallel = 1;
     amc->board = board;
+
+    aspeed_machine_class_props_init(oc);
 }
 
 static const TypeInfo aspeed_machine_type = {
@@ -334,6 +367,7 @@ static const TypeInfo aspeed_machine_type = {
     .parent = TYPE_MACHINE,
     .instance_size = sizeof(AspeedMachine),
     .class_size = sizeof(AspeedMachineClass),
+    .instance_init = aspeed_machine_instance_init,
     .abstract = true,
 };
 
-- 
2.17.1