From 86635aa4e9d627d5142b81c57a33dd1f36627d07 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 4 Jan 2021 17:13:19 +0000 Subject: hostmem-file: add readonly=on|off option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Liam Merwick Acked-by: Michael S. Tsirkin Message-Id: <20210104171320.575838-3-stefanha@redhat.com> Signed-off-by: Eduardo Habkost --- qemu-options.hx | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'qemu-options.hx') 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 -- cgit v1.2.3