Date: Fri, 12 Jan 2018 10:28:24 -0600
From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Raj, Ashok" <ashok.raj@intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        Arjan Van De Ven <arjan.van.de.ven@intel.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Peter Zijlstra <peterz@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Jun Nakajima <jun.nakajima@intel.com>,
        Asit Mallick <asit.k.mallick@intel.com>
Subject: Re: [PATCH 1/5] x86/ibrs: Introduce native_rdmsrl, and native_wrmsrl
Message-ID: <20180112162824.xenarh43dch62h5a@treble>
References: <1515720739-43819-1-git-send-email-ashok.raj@intel.com>
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On Thu, Jan 11, 2018 at 09:03:56PM -0800, Dave Hansen wrote:
> On 01/11/2018 07:01 PM, Raj, Ashok wrote:
> > On Thu, Jan 11, 2018 at 06:20:13PM -0800, Andy Lutomirski wrote:
> >> On Thu, Jan 11, 2018 at 5:52 PM, Raj, Ashok <ashok.raj@intel.com> wrote:
> >>>>
> >>>> What's wrong with native_read_msr()?
> >>>
> >>> Yes, i think i should have added to msr.h. The names didn't read as a
> >>> pair, one was native_read_msr, wrmsrl could be taken over when paravirt is
> >>> defined?
> >>
> >> Why do you need to override paravirt?
> > 
> > The idea was since these MSR's are passed through we shouldn't need to 
> > handle them any differently. Also its best to do this as soon as possible
> > and avoid longer paths to get this barrier to hardware.
> 
> We were also worried about the indirect calls that are part of the
> paravirt interfaces when retpolines are not in place.

But aren't those patched with direct calls during boot?

-- 
Josh