hostmem: allow preallocation of any memory region

And allow preallocation of file-based memory even without -mem-prealloc.
Some care is necessary because -mem-prealloc does not allow disabling
preallocation for hostmem-file.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/memory.c b/memory.c
index 5ef7167848..e7f1160f4e 100644
--- a/memory.c
+++ b/memory.c
@@ -1271,6 +1271,17 @@ void memory_region_reset_dirty(MemoryRegion *mr, hwaddr addr,
     cpu_physical_memory_reset_dirty(mr->ram_addr + addr, size, client);
 }
 
+int memory_region_get_fd(MemoryRegion *mr)
+{
+    if (mr->alias) {
+        return memory_region_get_fd(mr->alias);
+    }
+
+    assert(mr->terminates);
+
+    return qemu_get_ram_fd(mr->ram_addr & TARGET_PAGE_MASK);
+}
+
 void *memory_region_get_ram_ptr(MemoryRegion *mr)
 {
     if (mr->alias) {