Subject: Re: [PATCH 0/7] IBRS patch series
To: "Van De Ven, Arjan" <arjan.van.de.ven@intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        David Woodhouse <dwmw2@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <cover.1515086770.git.tim.c.chen@linux.intel.com>
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 <CA+55aFz+QcnA91H=bUh_oUogwhOaCY9qPqQkTdbeM-VanYGJVA@mail.gmail.com>
 <0575AF4FD06DD142AD198903C74E1CC87A56A873@ORSMSX103.amr.corp.intel.com>
From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <f13f81da-287d-8141-40c6-025c2e5cb28a@redhat.com>
Date: Fri, 5 Jan 2018 12:32:13 +0100
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On 04/01/2018 22:22, Van De Ven, Arjan wrote:
> this is about a level of paranoia you are comfortable with.
> 
> Retpoline on Skylake raises the bar for the issue enormously, but
> there are a set of corner cases that exist and that are not trivial
> to prove you dealt with them.
> 
> personally I am comfortable with retpoline on Skylake, but I would
> like to have IBRS as an opt in for the paranoid.
> 

IBRS actually seems to perform more than decently on Skylake with the
microcode updates we're shipping in RHEL---much more so than Broadwell
or Haswell.  Can you confirm that this is expected?

Paolo