memory: Introduce memory_region_init_reservation

Introduce a memory region type that can reserve I/O space. Such regions
are useful for modeling I/O that is only handled outside of QEMU, i.e.
in the context of an accelerator like KVM.

Any access to such a region from QEMU is a bug, but could theoretically
be triggered by guest code (DMA to reserved region). So only warning
about such events once, then ignore them.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/memory.h b/memory.h
index d48b08bf94..34c69cfc7a 100644
--- a/memory.h
+++ b/memory.h
@@ -126,6 +126,7 @@ struct MemoryRegion {
     bool readonly; /* For RAM regions */
     bool enabled;
     bool rom_device;
+    bool warning_printed; /* For reservations */
     MemoryRegion *alias;
     target_phys_addr_t alias_offset;
     unsigned priority;
@@ -280,6 +281,21 @@ void memory_region_init_rom_device(MemoryRegion *mr,
                                    uint64_t size);
 
 /**
+ * memory_region_init_reservation: Initialize a memory region that reserves
+ *                                 I/O space.
+ *
+ * A reservation region primariy serves debugging purposes.  It claims I/O
+ * space that is not supposed to be handled by QEMU itself.  Any access via
+ * the memory API will cause an abort().
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region.
+ */
+void memory_region_init_reservation(MemoryRegion *mr,
+                                    const char *name,
+                                    uint64_t size);
+/**
  * memory_region_destroy: Destroy a memory region and reclaim all resources.
  *
  * @mr: the region to be destroyed.  May not currently be a subregion