On 27.05.2026 06:23, Xinhui Yang wrote:
The motivation of the implementation is to make the systemd-nspawn
container to boot guest OSes with systemd v259+, otherwise any systemd
service requires importing credentials will fail, including journald,
D-Bus service and getty. We used to work around this issue by patching
systemd to retry the clone() without CLONE_NEWNS, which is not and can
not be implemented in QEMU user emulation.
mount(8) from util-linux works because it will fallback to the old
mount(2) syscall if fsmount(8) series of syscalls is not available.
Tested good on an x86-64 host, with:
- an AOSC OS mips64r6el guest, which boots successfully with full systemd
support using systemd-nspawn(1).
- a Gentoo ppc (big endian) guest, which boots successfully with full
systemd support, using systemd-nspawn(1).
Xinhui Yang (2):
linux-user: implement fsmount(2) series of syscalls
linux-user/strace: add fsmount series of syscalls
linux-user/strace.c | 102 +++++++++++++++++++++++++++++++++++++++++
linux-user/strace.list | 15 ++++++
linux-user/syscall.c | 77 +++++++++++++++++++++++++++++++
3 files changed, 194 insertions(+)
I'm picking this up for the active qemu stable series. This is a new
feature, but the new interfaces are used in more and more software, so
it becomes a defect not to have that interface :)
Thanks,
/mjt
