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authorStefan Hajnoczi2021-01-04 18:13:19 +0100
committerEduardo Habkost2021-02-01 23:07:34 +0100
commit86635aa4e9d627d5142b81c57a33dd1f36627d07 (patch)
treeeea6337f2e0f1661c4da093a987cafc7729a715a /qemu-options.hx
parentmemory: add readonly support to memory_region_init_ram_from_file() (diff)
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hostmem-file: add readonly=on|off option
Let -object memory-backend-file work on read-only files when the readonly=on option is given. This can be used to share the contents of a file between multiple guests while preventing them from consuming Copy-on-Write memory if guests dirty the pages, for example. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Liam Merwick <liam.merwick@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20210104171320.575838-3-stefanha@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'qemu-options.hx')
-rw-r--r--qemu-options.hx5
1 files changed, 4 insertions, 1 deletions
diff --git a/qemu-options.hx b/qemu-options.hx
index d0410f0512..c09c4646e2 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4426,7 +4426,7 @@ SRST
they are specified. Note that the 'id' property must be set. These
objects are placed in the '/objects' path.
- ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align``
+ ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,readonly=on|off``
Creates a memory file backend object, which can be used to back
the guest RAM with huge pages.
@@ -4509,6 +4509,9 @@ SRST
4.15) and the filesystem of ``mem-path`` mounted with DAX
option.
+ The ``readonly`` option specifies whether the backing file is opened
+ read-only or read-write (default).
+
``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave``
Creates a memory backend object, which can be used to back the
guest RAM. Memory backend objects offer more control than the