Accesses to unassigned io ports shall return -1 on read and be ignored
on write. Ensure these properties via dedicated ops, decoupling us from
the memory core's handling of unassigned accesses.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
exec.c | 3 ++-
include/exec/ioport.h | 2 ++
ioport.c | 16 ++++++++++++++++
3 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/exec.c b/exec.c
index 3ca9381..9ed598f 100644
--- a/exec.c
+++ b/exec.c
@@ -1820,7 +1820,8 @@ static void memory_map_init(void)
address_space_init(&address_space_memory, system_memory, "memory");
system_io = g_malloc(sizeof(*system_io));
- memory_region_init(system_io, NULL, "io", 65536);
+ memory_region_init_io(system_io, NULL, &unassigned_io_ops, NULL, "io",
+ 65536);
address_space_init(&address_space_io, system_io, "I/O");
memory_listener_register(&core_memory_listener, &address_space_memory);
diff --git a/include/exec/ioport.h b/include/exec/ioport.h
index bdd4e96..84f7f85 100644
--- a/include/exec/ioport.h
+++ b/include/exec/ioport.h
@@ -45,6 +45,8 @@ typedef struct MemoryRegionPortio {
#define PORTIO_END_OF_LIST() { }
+extern const MemoryRegionOps unassigned_io_ops;
+
void cpu_outb(pio_addr_t addr, uint8_t val);
void cpu_outw(pio_addr_t addr, uint16_t val);
void cpu_outl(pio_addr_t addr, uint32_t val);
diff --git a/ioport.c b/ioport.c
index 79b7f1a..707cce8 100644
--- a/ioport.c
+++ b/ioport.c
@@ -44,6 +44,22 @@ typedef struct MemoryRegionPortioList {
MemoryRegionPortio ports[];
} MemoryRegionPortioList;
+static uint64_t unassigned_io_read(void *opaque, hwaddr addr, unsigned size)
+{
+ return -1ULL;
+}
+
+static void unassigned_io_write(void *opaque, hwaddr addr, uint64_t val,
+ unsigned size)
+{
+}
+
+const MemoryRegionOps unassigned_io_ops = {
+ .read = unassigned_io_read,
+ .write = unassigned_io_write,
+ .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
void cpu_outb(pio_addr_t addr, uint8_t val)
{
LOG_IOPORT("outb: %04"FMT_pioaddr" %02"PRIx8"\n", addr, val);
--
1.7.3.4
