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, 7 insertions, 0 deletions

diff --git a/exec.c b/exec.c
index 997ef6a5a8..a27923a258 100644
--- a/exec.c
+++ b/exec.c
@@ -1448,6 +1448,13 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
 }
 #endif /* !_WIN32 */
 
+int qemu_get_ram_fd(ram_addr_t addr)
+{
+    RAMBlock *block = qemu_get_ram_block(addr);
+
+    return block->fd;
+}
+
 /* Return a host pointer to ram allocated with qemu_ram_alloc.
    With the exception of the softmmu code in this file, this should
    only be used for local memory (e.g. video ram) that the device owns,