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-rw-r--r--exec.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/exec.c b/exec.c
index 6b5828ee6e..4722e521d4 100644
--- a/exec.c
+++ b/exec.c
@@ -2725,6 +2725,37 @@ static uint16_t dummy_section(PhysPageMap *map, FlatView *fv, MemoryRegion *mr)
return phys_section_add(map, &section);
}
+static void readonly_mem_write(void *opaque, hwaddr addr,
+ uint64_t val, unsigned size)
+{
+ /* Ignore any write to ROM. */
+}
+
+static bool readonly_mem_accepts(void *opaque, hwaddr addr,
+ unsigned size, bool is_write)
+{
+ return is_write;
+}
+
+/* This will only be used for writes, because reads are special cased
+ * to directly access the underlying host ram.
+ */
+static const MemoryRegionOps readonly_mem_ops = {
+ .write = readonly_mem_write,
+ .valid.accepts = readonly_mem_accepts,
+ .endianness = DEVICE_NATIVE_ENDIAN,
+ .valid = {
+ .min_access_size = 1,
+ .max_access_size = 8,
+ .unaligned = false,
+ },
+ .impl = {
+ .min_access_size = 1,
+ .max_access_size = 8,
+ .unaligned = false,
+ },
+};
+
MemoryRegion *iotlb_to_region(CPUState *cpu, hwaddr index, MemTxAttrs attrs)
{
int asidx = cpu_asidx_from_attrs(cpu, attrs);
@@ -2737,7 +2768,8 @@ MemoryRegion *iotlb_to_region(CPUState *cpu, hwaddr index, MemTxAttrs attrs)
static void io_mem_init(void)
{
- memory_region_init_io(&io_mem_rom, NULL, &unassigned_mem_ops, NULL, NULL, UINT64_MAX);
+ memory_region_init_io(&io_mem_rom, NULL, &readonly_mem_ops,
+ NULL, NULL, UINT64_MAX);
memory_region_init_io(&io_mem_unassigned, NULL, &unassigned_mem_ops, NULL,
NULL, UINT64_MAX);