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-rw-r--r--qapi/qom.json17
1 files changed, 16 insertions, 1 deletions
diff --git a/qapi/qom.json b/qapi/qom.json
index fa3e88c8e6..c53ef978ff 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -668,6 +668,20 @@
# @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',
@@ -677,7 +691,8 @@
'*discard-data': 'bool',
'mem-path': 'str',
'*pmem': { 'type': 'bool', 'if': 'CONFIG_LIBPMEM' },
- '*readonly': 'bool' } }
+ '*readonly': 'bool',
+ '*rom': 'OnOffAuto' } }
##
# @MemoryBackendMemfdProperties: