nubus: add trace-events for empty slot accesses

Increase the max_access_size to 4 bytes for empty Nubus slot and super slot
accesses to allow tracing of the Nubus enumeration process by the guest OS.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20210924073808.1041-8-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

hw/nubus/nubus-bus.c

@@ -19,6 +19,7 @@
 #include "qemu/osdep.h"
 #include "hw/nubus/nubus.h"
 #include "qapi/error.h"
+#include "trace.h"
 
 
 static NubusBus *nubus_find(void)
@@ -31,12 +32,13 @@ static void nubus_slot_write(void *opaque, hwaddr addr, uint64_t val,
                              unsigned int size)
 {
     /* read only */
+    trace_nubus_slot_write(addr, val, size);
 }
 
-
 static uint64_t nubus_slot_read(void *opaque, hwaddr addr,
                                 unsigned int size)
 {
+    trace_nubus_slot_read(addr, size);
     return 0;
 }
 
@@ -46,7 +48,7 @@ static const MemoryRegionOps nubus_slot_ops = {
     .endianness = DEVICE_BIG_ENDIAN,
     .valid = {
         .min_access_size = 1,
-        .max_access_size = 1,
+        .max_access_size = 4,
     },
 };
 
@@ -54,11 +56,13 @@ static void nubus_super_slot_write(void *opaque, hwaddr addr, uint64_t val,
                                    unsigned int size)
 {
     /* read only */
+    trace_nubus_super_slot_write(addr, val, size);
 }
 
 static uint64_t nubus_super_slot_read(void *opaque, hwaddr addr,
                                       unsigned int size)
 {
+    trace_nubus_super_slot_read(addr, size);
     return 0;
 }
 
@@ -68,7 +72,7 @@ static const MemoryRegionOps nubus_super_slot_ops = {
     .endianness = DEVICE_BIG_ENDIAN,
     .valid = {
         .min_access_size = 1,
-        .max_access_size = 1,
+        .max_access_size = 4,
     },
 };
 

hw/nubus/trace-events

+# See docs/devel/tracing.txt for syntax documentation.
+
+# nubus-bus.c
+nubus_slot_read(uint64_t addr, int size) "reading unassigned addr 0x%"PRIx64 " size %d"
+nubus_slot_write(uint64_t addr, uint64_t val, int size) "writing unassigned addr 0x%"PRIx64 " value 0x%"PRIx64 " size %d"
+nubus_super_slot_read(uint64_t addr, int size) "reading unassigned addr 0x%"PRIx64 " size %d"
+nubus_super_slot_write(uint64_t addr, uint64_t val, int size) "writing unassigned addr 0x%"PRIx64 " value 0x%"PRIx64 " size %d"

hw/nubus/trace.h

+#include "trace/trace-hw_nubus.h"

meson.build

@@ -2142,6 +2142,7 @@ if have_system
     'hw/misc/macio',
     'hw/net',
     'hw/net/can',
+    'hw/nubus',
     'hw/nvme',
     'hw/nvram',
     'hw/pci',