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Date: Tue, 28 Mar 2017 14:46:19 +0200
From: Jiri Denemark <jdenemar@redhat.com>
Message-ID: <20170328124619.GI2455793@orkuz.home>
References: <20170327144815.8043-1-ehabkost@redhat.com>
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In-Reply-To: <20170327144815.8043-1-ehabkost@redhat.com>
Subject: Re: [Qemu-devel] [PATCH for-2.9 v2 0/2] i386: Don't override -cpu
 options on -cpu host/max
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To: Eduardo Habkost <ehabkost@redhat.com>
Cc: qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>, Igor Mammedov <imammedo@redhat.com>, "Collin L . Walling" <walling@linux.vnet.ibm.com>, Richard Henderson <rth@twiddle.net>, "Jason J . Herne" <jjherne@linux.vnet.ibm.com>

On Mon, Mar 27, 2017 at 11:48:13 -0300, Eduardo Habkost wrote:
> The existing code for "host" and "max" CPU models overrides every
> single feature in the CPU object at realize time, even the ones
> that were explicitly enabled or disabled by the user using
> "feat=on" or "feat=off", while features set using +feat/-feat are
> kept.
> 
> This means "-cpu host,+invtsc" works as expected, while
> "-cpu host,invtsc=on" doesn't.
> 
> This was a known bug, already documented in a comment inside
> x86_cpu_expand_features(). What makes this bug worse now is that
> libvirt 3.0.0 and newer now use "feat=on|off" instead of
> +feat/-feat when it detects a QEMU version that supports it (see
> libvirt commit d47db7b16dd5422c7e487c8c8ee5b181a2f9cd66).
> 
> This series fixes the bug.

Thanks.

Tested-by: Jiri Denemark <jdenemar@redhat.com>

Jirka