Re: [PATCH v2 0/3] nvdimm: read-only file support

[Liam Merwick]

On 16/09/2020 10:51, Stefan Hajnoczi wrote:
> v2:
>   * s/the the/the/ in documentation [Philippe]
>   * Assign nvdimm->unarmed earlier [Philippe]
>
> There is currently no way to back an NVDIMM with a read-only file so it can be
> safely shared between untrusted guests.
>
> Introduce an -object memory-backend-file,readonly=on|off option.
>
> Julio Montes sent an earlier patch here:
> https://patchew.org/QEMU/20190708211936.8037-1-julio.montes@intel.com/
>
> Eric Ernst requested this feature again for Kata Containers so I gave it a try.
>
> Stefan Hajnoczi (3):
>    memory: add readonly support to memory_region_init_ram_from_file()
>    hostmem-file: add readonly=on|off option
>    nvdimm: honor -object memory-backend-file,readonly=on option


Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>

(I just quickly modified kata-runtime to unconditionally pass 
readonly=on and verified that the root filesystem couldn't be remounted 
as rw)

Is this a candidate for 6.0?

Regards,
Liam


>   docs/nvdimm.txt           |  8 +++++++-
>   include/exec/memory.h     |  2 ++
>   include/exec/ram_addr.h   |  5 +++--
>   include/qemu/mmap-alloc.h |  2 ++
>   backends/hostmem-file.c   | 26 +++++++++++++++++++++++++-
>   exec.c                    | 18 +++++++++++-------
>   hw/mem/nvdimm.c           |  4 ++++
>   softmmu/memory.c          |  7 +++++--
>   util/mmap-alloc.c         | 10 ++++++----
>   util/oslib-posix.c        |  2 +-
>   qemu-options.hx           |  5 ++++-
>   11 files changed, 70 insertions(+), 19 deletions(-)