Re: [PATCH v3] tests/functional: add memlock tests

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Apr 15, 2025 at 02:08:55PM +0500, Alexandr Moshkov wrote:
> Add new tests to check the correctness of the `-overcommit memlock`
> option (possible values: off, on, on-fault) by using
> `/proc/{qemu_pid}/smaps` file to check in Size, Rss and Locked fields of
> anonymous segments:
> 
> * if `memlock=off`, then Locked = 0 on every anonymous smaps;
> * if `memlock=on`, then Size, Rss and Locked values must be equal for
> every anon smaps where Rss is not 0;
> * if `memlock=on-fault`, then Rss and Locked must be equal on every anon
> smaps and anonymous segment with Rss < Size must exists.

How are you running this test ?  Unprivileged users don't get to
lock any non-trivial amount of memory by default, and QEMU functional
tests pretty much exclusively get run as an unprivileged user account.

This test immediately fails when run:

  qemu.machine.machine.VMLaunchFailure: ConnectError: Failed to establish session: EOFError
	Exit code: 1
	Command: ./build/qemu-system-x86_64 -display none -vga none -chardev socket,id=mon,fd=5 -mon chardev=mon,mode=control -overcommit mem-lock=on
	Output: qemu-system-x86_64: mlockall: Cannot allocate memory
        qemu-system-x86_64: locking memory failed

and we don't expect users to run anything as root.

> Signed-off-by: Alexandr Moshkov <dtalexundeer@yandex-team.ru>
> ---
>  tests/functional/meson.build     |   1 +
>  tests/functional/test_memlock.py | 100 +++++++++++++++++++++++++++++++
>  2 files changed, 101 insertions(+)
>  create mode 100644 tests/functional/test_memlock.py

Test files need to have execute permission set.

> 

With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|