Alexander Graf <g...@amazon.com> writes:
> Add an option for hostmem-file to start the memory object at an offset
> into the target file. This is useful if multiple memory objects reside
> inside the same target file, such as a device node.
>
> In particular, it's useful to map guest memory directly into /dev/mem
> for experimentation.
>
> Signed-off-by: Alexander Graf <g...@amazon.com>
[...]
> diff --git a/qapi/qom.json b/qapi/qom.json
> index a877b879b9..8f5eaa8415 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -635,6 +635,10 @@
> # specify the required alignment via this option.
> # 0 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 overload multiple regions into a single fils.
single file
I'm not sure about "to overload multiple regions into a single file".
Maybe "to back multiple regions with a single file".
Any alignment requirements?
What happens when the regions overlap?
> +# (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.
> Note
> # that ``discard-data`` is only an optimization, and QEMU
> might
> @@ -655,6 +659,7 @@
> { 'struct': 'MemoryBackendFileProperties',
> 'base': 'MemoryBackendProperties',
> 'data': { '*align': 'size',
> + '*offset': 'size',
> '*discard-data': 'bool',
> 'mem-path': 'str',
> '*pmem': { 'type': 'bool', 'if': 'CONFIG_LIBPMEM' },
[...]
