Paolo Bonzini <pbonz...@redhat.com> writes: > On 11/11/20 16:03, Daniel P. Berrangé wrote: >> On Wed, Nov 11, 2020 at 08:57:16AM -0500, Paolo Bonzini wrote: >>> -set as far as I can see has basically no use. It was intended as an >>> override >>> mechanism for configuration files, but even configuration files themselves >>> are hardly used. Drop it with prejudice. >>> >>> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> >>> --- >>> docs/system/deprecated.rst | 6 ++++++ >>> include/qemu/config-file.h | 1 - >>> qemu-options.hx | 9 --------- >>> softmmu/vl.c | 4 ---- >>> util/qemu-config.c | 33 --------------------------------- >>> 5 files changed, 6 insertions(+), 47 deletions(-) >> >> iotest 068 uses -set and qtest vhost-user-text.c also does >> IOW, it looks like it is valid to use -set, even if you're not using >> -readconfig.
Of course that's valid. >> Libvirt doesn't use -set, but we've had users who make use of >> libvirt >> command line passthrough for QEMU with -set. > > Hmm, indeed: > > https://patchwork.kernel.org/project/qemu-devel/patch/20181218041625.24969-16-...@redhat.com/ Such monkey-patching may not be wise, but unwise != invalid. >> IOW, I'm not convinced real world usage is near zero as suggested. Guessing the gamut of usage out there in the real world correctly is always a tall order :) > Yes, perhaps it's not. :) Though for both tests you pointed out it's > even cleaner not to use it, there seems to be real world usage at > least with "device". I have common test configurations files for -readconfig. I've used -set for quick monkey-patching once in a great while. Now, such ad hoc use is a *weak* argument against ditching the feature. But it does undermine the "basically no use" proposition. > It is probably more viable to deprecate or even forbid usage of "-set" > with anything but "device". vhost-user-test.c would still be > affected, but it's a relatively small patch. Deprecating only some uses buys us next to nothing, I think. If we want to deprecate it, just deprecate it. Immediate removal of -set / rejection of -set for some option groups needs more justification than just "I think we can get away with it": there has to be a tangible benefit. What would immediate removal buy us over the orthodox "deprecate, wait for grace period to expire, remove"?