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.
Cc: qemu-stable@nongnu.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/ioport.c b/ioport.c
index 79b7f1a..707cce8 100644
--- a/ioport.c
+++ b/ioport.c
@@ -44,6 +44,22 @@
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);
