From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51EF4C3A59E for ; Thu, 5 Sep 2019 01:49:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BEC220882 for ; Thu, 5 Sep 2019 01:49:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567648185; bh=zo9ULV+hpAXsuDOpSM2OjIMnQQSkYg7lHRWUmgT2DiI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=y2uA2A0DsqrFqYs5wPAkXhlyFEYudoQnztsnaJq1bhX/waxZH0OziDmKRl4XZrLks l6z+1NXcqR6YPKXmoYQRx2n5t3Rf/HfzRot60bzPjZYnDkwwvg+dsP4FVPM5uVParU BxpgvqCZlDdisX7We5iQgyYB+teecCN9/zLJhxN0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730628AbfIEBto (ORCPT ); Wed, 4 Sep 2019 21:49:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:34182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727156AbfIEBto (ORCPT ); Wed, 4 Sep 2019 21:49:44 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4EB0B20644; Thu, 5 Sep 2019 01:49:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567648183; bh=zo9ULV+hpAXsuDOpSM2OjIMnQQSkYg7lHRWUmgT2DiI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Spbz7M6vwU7hElCNqtXo3bKV+4/MX5UPtIN8l2p64GEiBqZISlxfa5bc1OunLPkii bjeBNfoO6cFJ+tXKjrc3gwOfSyZt/cOnKZ4x/xtyWeGsP5iif9c19VeSAr71jIuM6U DBVkcDC04fNdgCH4YhXG55EE5a7IGmP7Qh4b0Q98= Date: Thu, 5 Sep 2019 10:49:37 +0900 From: Masami Hiramatsu To: Andrew Cooper Cc: Ingo Molnar , Juergen Gross , Stefano Stabellini , Peter Zijlstra , Randy Dunlap , , , Borislav Petkov , Josh Poimboeuf , , Boris Ostrovsky Subject: Re: [Xen-devel] [PATCH -tip 0/2] x86: Prohibit kprobes on XEN_EMULATE_PREFIX Message-Id: <20190905104937.60aa03f699a9c0fbf1b651b9@kernel.org> In-Reply-To: References: <156759754770.24473.11832897710080799131.stgit@devnote2> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 4 Sep 2019 12:54:55 +0100 Andrew Cooper wrote: > On 04/09/2019 12:45, Masami Hiramatsu wrote: > > Hi, > > > > These patches allow x86 instruction decoder to decode > > xen-cpuid which has XEN_EMULATE_PREFIX, and prohibit > > kprobes to probe on it. > > > > Josh reported that the objtool can not decode such special > > prefixed instructions, and I found that we also have to > > prohibit kprobes to probe on such instruction. > > > > This series can be applied on -tip master branch which > > has merged Josh's objtool/perf sharing common x86 insn > > decoder series. > > The paravirtualised xen-cpuid is were you'll see it most in a regular > kernel, but be aware that it is also used for testing purposes in other > circumstances, and there is an equivalent KVM prefix which is used for > KVM testing. Good catch! I didn't notice that. Is that really same sequance or KVM uses another sequence of instructions for KVM prefix? > > It might be better to generalise the decode support to "virtualisation > escape prefix" or something slightly more generic. Agreed, it is easy to expand it, we can switch the prefix template. Could you tell me where I should look? I will add it. Thank you, > > ~Andrew -- Masami Hiramatsu From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A409BC3A59E for ; Thu, 5 Sep 2019 01:50:20 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 70CDE20644 for ; Thu, 5 Sep 2019 01:50:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Spbz7M6v" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 70CDE20644 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1i5guI-000798-Gc; Thu, 05 Sep 2019 01:49:54 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1i5guH-000791-F7 for xen-devel@lists.xenproject.org; Thu, 05 Sep 2019 01:49:53 +0000 X-Inumbo-ID: 6e85d9d4-cf7f-11e9-978d-bc764e2007e4 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 6e85d9d4-cf7f-11e9-978d-bc764e2007e4; Thu, 05 Sep 2019 01:49:43 +0000 (UTC) Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4EB0B20644; Thu, 5 Sep 2019 01:49:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567648183; bh=zo9ULV+hpAXsuDOpSM2OjIMnQQSkYg7lHRWUmgT2DiI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Spbz7M6vwU7hElCNqtXo3bKV+4/MX5UPtIN8l2p64GEiBqZISlxfa5bc1OunLPkii bjeBNfoO6cFJ+tXKjrc3gwOfSyZt/cOnKZ4x/xtyWeGsP5iif9c19VeSAr71jIuM6U DBVkcDC04fNdgCH4YhXG55EE5a7IGmP7Qh4b0Q98= Date: Thu, 5 Sep 2019 10:49:37 +0900 From: Masami Hiramatsu To: Andrew Cooper Message-Id: <20190905104937.60aa03f699a9c0fbf1b651b9@kernel.org> In-Reply-To: References: <156759754770.24473.11832897710080799131.stgit@devnote2> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Subject: Re: [Xen-devel] [PATCH -tip 0/2] x86: Prohibit kprobes on XEN_EMULATE_PREFIX X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Stefano Stabellini , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov , Randy Dunlap , Josh Poimboeuf , xen-devel@lists.xenproject.org, Boris Ostrovsky , Ingo Molnar Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" T24gV2VkLCA0IFNlcCAyMDE5IDEyOjU0OjU1ICswMTAwCkFuZHJldyBDb29wZXIgPGFuZHJldy5j b29wZXIzQGNpdHJpeC5jb20+IHdyb3RlOgoKPiBPbiAwNC8wOS8yMDE5IDEyOjQ1LCBNYXNhbWkg SGlyYW1hdHN1IHdyb3RlOgo+ID4gSGksCj4gPgo+ID4gVGhlc2UgcGF0Y2hlcyBhbGxvdyB4ODYg aW5zdHJ1Y3Rpb24gZGVjb2RlciB0byBkZWNvZGUKPiA+IHhlbi1jcHVpZCB3aGljaCBoYXMgWEVO X0VNVUxBVEVfUFJFRklYLCBhbmQgcHJvaGliaXQKPiA+IGtwcm9iZXMgdG8gcHJvYmUgb24gaXQu Cj4gPgo+ID4gSm9zaCByZXBvcnRlZCB0aGF0IHRoZSBvYmp0b29sIGNhbiBub3QgZGVjb2RlIHN1 Y2ggc3BlY2lhbAo+ID4gcHJlZml4ZWQgaW5zdHJ1Y3Rpb25zLCBhbmQgSSBmb3VuZCB0aGF0IHdl IGFsc28gaGF2ZSB0bwo+ID4gcHJvaGliaXQga3Byb2JlcyB0byBwcm9iZSBvbiBzdWNoIGluc3Ry dWN0aW9uLgo+ID4KPiA+IFRoaXMgc2VyaWVzIGNhbiBiZSBhcHBsaWVkIG9uIC10aXAgbWFzdGVy IGJyYW5jaCB3aGljaAo+ID4gaGFzIG1lcmdlZCBKb3NoJ3Mgb2JqdG9vbC9wZXJmIHNoYXJpbmcg Y29tbW9uIHg4NiBpbnNuCj4gPiBkZWNvZGVyIHNlcmllcy4KPiAKPiBUaGUgcGFyYXZpcnR1YWxp c2VkIHhlbi1jcHVpZCBpcyB3ZXJlIHlvdSdsbCBzZWUgaXQgbW9zdCBpbiBhIHJlZ3VsYXIKPiBr ZXJuZWwsIGJ1dCBiZSBhd2FyZSB0aGF0IGl0IGlzIGFsc28gdXNlZCBmb3IgdGVzdGluZyBwdXJw b3NlcyBpbiBvdGhlcgo+IGNpcmN1bXN0YW5jZXMsIGFuZCB0aGVyZSBpcyBhbiBlcXVpdmFsZW50 IEtWTSBwcmVmaXggd2hpY2ggaXMgdXNlZCBmb3IKPiBLVk0gdGVzdGluZy4KCkdvb2QgY2F0Y2gh IEkgZGlkbid0IG5vdGljZSB0aGF0LiBJcyB0aGF0IHJlYWxseSBzYW1lIHNlcXVhbmNlIG9yIEtW TSB1c2VzCmFub3RoZXIgc2VxdWVuY2Ugb2YgaW5zdHJ1Y3Rpb25zIGZvciBLVk0gcHJlZml4PwoK PiAKPiBJdCBtaWdodCBiZSBiZXR0ZXIgdG8gZ2VuZXJhbGlzZSB0aGUgZGVjb2RlIHN1cHBvcnQg dG8gInZpcnR1YWxpc2F0aW9uCj4gZXNjYXBlIHByZWZpeCIgb3Igc29tZXRoaW5nIHNsaWdodGx5 IG1vcmUgZ2VuZXJpYy4KCkFncmVlZCwgaXQgaXMgZWFzeSB0byBleHBhbmQgaXQsIHdlIGNhbiBz d2l0Y2ggdGhlIHByZWZpeCB0ZW1wbGF0ZS4KQ291bGQgeW91IHRlbGwgbWUgd2hlcmUgSSBzaG91 bGQgbG9vaz8gSSB3aWxsIGFkZCBpdC4KClRoYW5rIHlvdSwKCgo+IAo+IH5BbmRyZXcKCgotLSAK TWFzYW1pIEhpcmFtYXRzdSA8bWhpcmFtYXRAa2VybmVsLm9yZz4KCl9fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fClhlbi1kZXZlbCBtYWlsaW5nIGxpc3QKWGVu LWRldmVsQGxpc3RzLnhlbnByb2plY3Qub3JnCmh0dHBzOi8vbGlzdHMueGVucHJvamVjdC5vcmcv bWFpbG1hbi9saXN0aW5mby94ZW4tZGV2ZWw=