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Date: Wed, 31 Jan 2018 17:28:46 +0100
From: Borislav Petkov <bp@suse.de>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Christophe de Dinechin <christophe.de.dinechin@gmail.com>,
	Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Arjan van de Ven <arjan@linux.intel.com>,
	KarimAllah Ahmed <karahmed@amazon.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andi Kleen <ak@linux.intel.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andy Lutomirski <luto@kernel.org>, Ashok Raj <ashok.raj@intel.com>,
	Asit Mallick <asit.k.mallick@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"H . Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>,
	Joerg Roedel <joro@8bytes.org>,
	Jun Nakajima <jun.nakajima@intel.com>,
	Laura Abbott <labbott@redhat.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	KVM list <kvm@vger.kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [RFC,05/10] x86/speculation: Add basic IBRS support
 infrastructure
Message-ID: <20180131162846.x2fnp2h3spvr5xao@pd.tnic>
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On Wed, Jan 31, 2018 at 12:44:41PM -0200, Eduardo Habkost wrote:
> Also, if anybody don't like it, users can already specify, e.g.,
> "Broadwell,-hle,-rtm" or "Skylake,+spec_ctrl".
> 
> QEMU only adds have the -noTSX and -IBRS CPU for convenience of
> management systems that don't know how to check/configure
> individual CPU features.  We're working with libvirt and
> OpenStack folks to make this kind of trick unnecessary.

Yeah, defining separate CPU models just for that seems hacky. The
+/-<feature> specification looks like the Right Thing(tm) to do.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--