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From: Thomas Huth <thuth@redhat.com>
Message-ID: <176d87e9-d899-792f-536e-07cd6f5c7cb6@redhat.com>
Date: Tue, 2 May 2017 17:53:54 +0200
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Subject: Re: [Qemu-devel] [PATCH] Deprecate '-enable-kvm' and '-enable-hax'
 in favour of '-accel'
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To: Paolo Bonzini <pbonzini@redhat.com>, Markus Armbruster <armbru@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>, qemu-devel@nongnu.org, Vincent Palatin <vpalatin@chromium.org>

On 02.05.2017 17:09, Paolo Bonzini wrote:
>=20
>=20
> On 02/05/2017 17:01, Markus Armbruster wrote:
>>> But I really, really see no point in removing --enable-kvm.  It costs
>>> perhaps 10 lines of code that has pretty much no ramifications elsewh=
ere
>>> in the code.  If anything I'd expect "-machine accel" to disappear
>>> before, if ever (in favor of multiple "-accel" options, e.g. "-machin=
e
>>> accel=3Dkvm:tcg" can become "-accel kvm -accel tcg".
>> I basically agree, except I wouldn't say "no point", but "doesn't buy =
us
>> enough to justify inconveniencing users".
>>
>> What we've done before for options that have become unloved, but not
>> harmful, is remove them just from documentation.  Grep qemu-options.hx
>> for "HXCOMM Deprecated".  Let's do that for --enable-kvm and similarly
>> weird sugared options.
>=20
> Except that this provides no easily greppable way to find how to enable
> KVM, as things stand.

Should we then improve the description of the -accel parameter?

> So the first lesson should be "no deprecation
> without documentation" (any reference to 18th century political slogans
> is purely coincidential :)).

Would you accept my patch if I'd remove the hunks for vl.c, i.e. a patch
that just updates the documentation?

 Thomas


PS: Thinking about all of this again, I think the thing that bugs me
most is that we now have a brand new "-enable-hax" option, too, but no
"-enable-xen" option ... that's just inconsistent. What do you think
about removing the "-enable-hax" option again - there should only be
very few users for this option so far, so the impact should be low. HAX
users could simply use the "-accel hax" instead...