Merge tag 'pull-loongarch-20231103' of https://gitlab.com/gaosong/qemu into staging

[mirror_qemu.git] / qapi / qom.json

diff --git a/qapi/qom.json b/qapi/qom.json
index 7f92ea43e8e1e9e80f974098994344df69158a13..c53ef978ff7e6a81f8c926159fe52c0d349696ac 100644 (file)
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -647,9 +647,10 @@
 #     selects a default alignment (currently the page size).
 #     (default: 0)
 #
-# @offset: the offset into the target file that the region starts at. You
-#     can use this option to back multiple regions with a single file. Must
-#     be a multiple of the page size. (default: 0) (since 8.1)
+# @offset: the offset into the target file that the region starts at.
+#     You can use this option to back multiple regions with a single
+#     file. Must be a multiple of the page size.
+#     (default: 0) (since 8.1)
 #
 # @discard-data: if true, the file contents can be destroyed when QEMU
 #     exits, to avoid unnecessarily flushing data to the backing file.
@@ -662,11 +663,25 @@
 #
 # @pmem: specifies whether the backing file specified by @mem-path is
 #     in host persistent memory that can be accessed using the SNIA
-#     NVM programming model (e.g.  Intel NVDIMM).
+#     NVM programming model (e.g. Intel NVDIMM).
 #
 # @readonly: if true, the backing file is opened read-only; if false,
 #     it is opened read-write.  (default: false)
 #
+# @rom: whether to create Read Only Memory (ROM) that cannot be modified
+#       by the VM.  Any write attempts to such ROM will be denied.  Most
+#       use cases want writable RAM instead of ROM.  However, selected use
+#       cases, like R/O NVDIMMs, can benefit from ROM.  If set to 'on',
+#       create ROM; if set to 'off', create writable RAM;  if set to
+#       'auto', the value of the @readonly property is used.  This
+#       property is primarily helpful when we want to have proper RAM in
+#       configurations that would traditionally create ROM before this
+#       property was introduced: VM templating, where we want to open a
+#       file readonly (@readonly set to true) and mark the memory to be
+#       private for QEMU (@share set to false).  For this use case, we need
+#       writable RAM instead of ROM, and want to set this property to 'off'.
+#       (default: auto, since 8.2)
+#
 # Since: 2.1
 ##
 { 'struct': 'MemoryBackendFileProperties',
@@ -676,7 +691,8 @@
             '*discard-data': 'bool',
             'mem-path': 'str',
             '*pmem': { 'type': 'bool', 'if': 'CONFIG_LIBPMEM' },
-            '*readonly': 'bool' } }
+            '*readonly': 'bool',
+            '*rom': 'OnOffAuto' } }
 
 ##
 # @MemoryBackendMemfdProperties: