Commit 3bb28b72 authored by Jan Kiszka's avatar Jan Kiszka Committed by Paolo Bonzini
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memory: Provide separate handling of unassigned io ports accesses

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: default avatarJan Kiszka <>
Signed-off-by: default avatarPaolo Bonzini <>
parent 88266249
......@@ -1805,7 +1805,8 @@ 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",
address_space_init(&address_space_io, system_io, "I/O");
memory_listener_register(&core_memory_listener, &address_space_memory);
......@@ -45,6 +45,10 @@ 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);
......@@ -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,
void cpu_outb(pio_addr_t addr, uint8_t val)
LOG_IOPORT("outb: %04"FMT_pioaddr" %02"PRIx8"\n", addr, val);
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