Re: [libvirt PATCH v2 2/3] build: Add userfaultfd_sysctl build option

On Tue, Feb 13, 2024 at 11:39:26 +0100, Jiri Denemark wrote: > This option controls whether the sysctl config for enabling unprivileged > userfaultfd will be installed. > > Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; > --- > meson.build | 8 ++++++++ > meson_options.txt | 1 + > src/qemu/meson.build | 2 +- > 3 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/meson.build b/meson.build > index e1c70fce92..dbd9cad6df 100644 > --- a/meson.build > +++ b/meson.build > @@ -2019,6 +2019,12 @@ elif get_option('sysctl_config').enabled() > error('sysctl configuration is supported only on linux') > endif > > +if not get_option('userfaultfd_sysctl').disabled() and conf.has('WITH_SYSCTL') > + conf.set('WITH_USERFAULTFD_SYSCTL', 1) > +elif get_option('userfaultfd_sysctl').enabled() > + error('userfaultfd_sysctl option requires sysctl_config to be enabled') > +endif > + > conf.set_quoted('TLS_PRIORITY', get_option('tls_priority')) > > > @@ -2318,6 +2324,8 @@ misc_summary = { > 'virt-login-shell': conf.has('WITH_LOGIN_SHELL'), > 'virt-host-validate': conf.has('WITH_HOST_VALIDATE'), > 'TLS priority': conf.get_unquoted('TLS_PRIORITY'), > + 'sysctl config': conf.has('WITH_SYSCTL'), > + 'userfaultfd sysctl': conf.has('WITH_USERFAULTFD_SYSCTL'), > } > summary(misc_summary, section: 'Miscellaneous', bool_yn: true, list_sep: ' ') > > diff --git a/meson_options.txt b/meson_options.txt > index 182e28b3d1..ed91d97abf 100644 > --- a/meson_options.txt > +++ b/meson_options.txt > @@ -108,4 +108,5 @@ option('nbdkit', type: 'feature', value: 'auto', description: 'Build nbdkit stor > option('nbdkit_config_default', type: 'feature', value: 'auto', description: 'Whether to use nbdkit storage backend for network disks by default (configurable)') > option('pm_utils', type: 'feature', value: 'auto', description: 'use pm-utils for power management') > option('sysctl_config', type: 'feature', value: 'auto', description: 'Whether to install sysctl configs') > +option('userfaultfd_sysctl', type: 'feature', value: 'auto', description: 'Whether to install sysctl config for enabling unprivileged userfaultfd') > option('tls_priority', type: 'string', value: 'NORMAL', description: 'set the default TLS session priority string') So this change apparently broke mingw build on Fedora: ERROR: Problem encountered: userfaultfd_sysctl option requires sysctl_config to be enabled The mingw part of libvirt.spec runs meson setup with -Dsysctl_config=disabled and does not specify -Duserfaultfd_sysctl at all, which I would expect means the same as -Duserfaultfd_sysctl=auto. But according to the error message it looks like userfaultfd_sysctl was actually enabled. I didn't explicitly test mingw builds, but I tested running meson setup with all combinations, especially with -Dsysctl_config=disabled and not specifying userfaultfd_sysctl option at all and it worked as expected: sysctl config : NO userfaultfd sysctl : NO Sure, I can easily fix this by passing -Duserfaultfd_sysctl=disable for mingw builds, but I'm wondering why the build doesn't work with just -Dsysctl_config=disabled?