portio: Allow to mark portio lists as coalesced MMIO flushing

This will enable us to remove all remaining explicit calls of
qemu_flush_coalesced_mmio_buffer in IO handlers.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/exec/ioport.h

@@ -64,11 +64,13 @@ typedef struct PortioList {
     struct MemoryRegion **regions;
     void *opaque;
     const char *name;
+    bool flush_coalesced_mmio;
 } PortioList;
 
 void portio_list_init(PortioList *piolist, Object *owner,
                       const struct MemoryRegionPortio *callbacks,
                       void *opaque, const char *name);
+void portio_list_set_flush_coalesced(PortioList *piolist);
 void portio_list_destroy(PortioList *piolist);
 void portio_list_add(PortioList *piolist,
                      struct MemoryRegion *address_space,

ioport.c

@@ -139,6 +139,12 @@ void portio_list_init(PortioList *piolist,
     piolist->opaque = opaque;
     piolist->owner = owner;
     piolist->name = name;
+    piolist->flush_coalesced_mmio = false;
+}
+
+void portio_list_set_flush_coalesced(PortioList *piolist)
+{
+    piolist->flush_coalesced_mmio = true;
 }
 
 void portio_list_destroy(PortioList *piolist)
@@ -231,6 +237,9 @@ static void portio_list_add_1(PortioList *piolist,
      */
     memory_region_init_io(&mrpio->mr, piolist->owner, &portio_ops, mrpio,
                           piolist->name, off_high - off_low);
+    if (piolist->flush_coalesced_mmio) {
+        memory_region_set_flush_coalesced(&mrpio->mr);
+    }
     memory_region_add_subregion(piolist->address_space,
                                 start + off_low, &mrpio->mr);
     piolist->regions[piolist->nr] = &mrpio->mr;