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Date: Thu, 6 Oct 2016 17:55:25 +0200
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v4 7/8] intel_iommu: keep buggy EIM enabled
 in 2.7 machine type
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>, qemu-devel@nongnu.org, Peter Xu <peterx@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <rth@twiddle.net>

2016-10-06 18:33+0300, Michael S. Tsirkin:
> On Thu, Oct 06, 2016 at 11:51:42AM -0300, Eduardo Habkost wrote:
>> On Wed, Oct 05, 2016 at 03:06:56PM +0200, Radim Kr=C4=8Dm=C3=A1=C5=99 =
wrote:
>> > QEMU 2.7 allowed EIM even in configurations that were forbidden in t=
he
>> > last patch because they were not working, like old KVM or userspace
>> > APIC.  In order to keep backward compatibility, we again allow guest=
s to
>> > misbehave in non-obvious ways, and make it the default for old machi=
ne
>> > types.
>> >=20
>> > A user can enable the buggy mode it with "buggy_eim=3Don", which is =
weird,
>> > but I don't know how to add a private property.
>>=20
>> Properties et by compat_props are always user-visible. I believe
>> that's a feature (this way, it will be possible to let management
>> software and other tools know what exactly is behind a
>> machine-type).
>=20
> There's a rule that any name beginning with x- is deemed
> experimental. See docs/qmp-spec.txt.
> It is a good idea to always use this for compat properties as
> we want to be able to drop them when we drop the old
> machine type.

"x-buggy-eim" should deter most users, thanks.

pc-0.10 seems to be the first machine type ever (2009), is there already
a plan to deprecate it?