Re: [Qemu-devel] [PATCH 0/2] target-i386: "custom" CPU model + script to dump existing CPU models

From: "Andreas Färber" <afaerber@suse.de>
To: Jiri Denemark <jdenemar@redhat.com>
Cc: mimu@linux.vnet.ibm.com, "Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>,
	borntraeger@de.ibm.com, Igor Mammedov <imammedo@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	rth@twiddle.net, Eduardo Habkost <ehabkost@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 0/2] target-i386: "custom" CPU model + script to dump existing CPU models
Date: Tue, 23 Jun 2015 14:32:00 +0200	[thread overview]
Message-ID: <558951C0.3050806@suse.de> (raw)
In-Reply-To: <20150608201835.GM3525@orkuz.home>

Am 08.06.2015 um 22:18 schrieb Jiri Denemark:
>> To help libvirt in the transition, a x86-cpu-model-dump script is provided,
>> that will generate a config file that can be loaded using -readconfig, based on
>> the -cpu and -machine options provided in the command-line.
> 
> Thanks Eduardo, I never was a big fan of moving (or copying) all the CPU
> configuration data to libvirt, but now I think it actually makes sense.
> We already have a partial copy of CPU model definitions in libvirt
> anyway, but as QEMU changes some CPU models in some machine types (and
> libvirt does not do that) we have no real control over the guest CPU
> configuration. While what we really want is full control to enforce
> stable guest ABI.

That sounds like FUD to me. Any concrete data points where QEMU does not
have a stable ABI for x86 CPUs? That's what we have the pc*-x.y machines
for.

Regards,
Andreas

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