From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751728AbdKIGO6 (ORCPT <rfc822;w@1wt.eu>);
        Thu, 9 Nov 2017 01:14:58 -0500
Received: from mga11.intel.com ([192.55.52.93]:8227 "EHLO mga11.intel.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751130AbdKIGO4 (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 9 Nov 2017 01:14:56 -0500
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.44,368,1505804400"; 
   d="scan'208";a="5552788"
Date: Wed, 8 Nov 2017 22:13:16 -0800
From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>, Peter Anvin <hpa@zytor.com>,
        Borislav Petkov <bp@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
        Tony Luck <tony.luck@intel.com>, Fenghua Yu <fenghua.yu@intel.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Brian Gerst <brgerst@gmail.com>, Jonathan Corbet <corbet@lwn.net>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Chris Metcalf <cmetcalf@mellanox.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Andrew Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>, ray.huang@amd.com,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, Chen Yucong <slaoub@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, Jiri Slaby <jslaby@suse.cz>,
        Shuah Khan <shuah@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        "linux-tip-commits@vger.kernel.org" 
        <linux-tip-commits@vger.kernel.org>
Subject: Re: [tip:x86/asm] x86/umip: Add emulation code for UMIP instructions
Message-ID: <20171109061316.GE30507@voyager>
References: <1509935277-22138-8-git-send-email-ricardo.neri-calderon@linux.intel.com>
 <tip-1e5db223696afa55e6a038fac638f759e1fdcc01@git.kernel.org>
 <ca980b88-a668-29cc-3f5a-506088473282@redhat.com>
 <CA+55aFyzb5D6DfM_1mxcMbuYOaxZWFxqfv7WZS6zdkqnN7+p0A@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+55aFyzb5D6DfM_1mxcMbuYOaxZWFxqfv7WZS6zdkqnN7+p0A@mail.gmail.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Nov 08, 2017 at 08:34:45AM -0800, Linus Torvalds wrote:
> On Wed, Nov 8, 2017 at 8:14 AM, Denys Vlasenko <dvlasenk@redhat.com> wrote:
> >
> > Can we avoid maintain emulation of these isns, by asking Wine to remove
> > their use instead?
> 
> If we ask the Wine people to remove the instruction use, that may mean
> that we can avoid the emulation in four or five _years_ once everybody
> has updated.
> 
> But it wouldn't mean that we could avoid it today.
> 
> We *do* probably want to print a warning about these instructions,
> whether emulated or not. If emulated, we want to print a warning about
> the emulation being expensive (as a nudge to the Wine people to not do
> that), and if _not_ emulated, we'd want to print a warning about why
> people suddenly got a SIGSEGV in case there are programs that use
> those instructions that people didn't even think of.

I am preparing a set of complementary patches now that the series made it
to the tip tree. I can include these updates as well.
> 
> But make it ratelimit the warning (perhaps at most once every few
> minutes or whatever), so that people won't flood message logs just
> because they have old stupid programs that use those things.

Will do.

Thanks and BR,
Ricardo