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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 5B033C433E1 for ; Fri, 21 Aug 2020 20:02:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 252982072D for ; Fri, 21 Aug 2020 20:02:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IvMN3Cmy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726885AbgHUUC2 (ORCPT ); Fri, 21 Aug 2020 16:02:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726300AbgHUUC0 (ORCPT ); Fri, 21 Aug 2020 16:02:26 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29943C061573; Fri, 21 Aug 2020 13:02:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Qf+C/vALCJLHCuDIud0TGurzvmff61svtox7fx2n034=; b=IvMN3CmydmyLRnC/Z64Dfsiu5o Q6GrLp8CRovAv+EfD4cQOgWuIrvZGCSZmArYdin9VECt28XzksU5sf3mX4ctw2y3YAJYBdvuT1MqI Qe1l0UhtRjPM7YwELz0VY+Nr2kuoBQ6iUBYypjWS1RClKleXxkqTP3vQnoUEsVZsXcDOz9kYDAGyL JG/Tzps5K2flaBON/nE/XMDp48GqqKWbkEZsEtJ7nwddb3xtqkpDXVvE5Vve0tCmQIeQPyQh9wEH3 pKM0fHTIQmt3Mv0m58pQZBs59mjqmvni7tU/bUx56GAJ52pDkXoL8bhZ9L8V+V6TVpKpBTTrVgYDV jWtC57AQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k9DEm-0007AP-Bb; Fri, 21 Aug 2020 20:02:08 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id F3962980DF7; Fri, 21 Aug 2020 22:02:07 +0200 (CEST) Date: Fri, 21 Aug 2020 22:02:07 +0200 From: Peter Zijlstra To: hpa@zytor.com Cc: Thomas Gleixner , Paolo Bonzini , Borislav Petkov , Sean Christopherson , Andy Lutomirski , Ingo Molnar , x86@kernel.org, linux-kernel@vger.kernel.org, Dave Hansen , Chang Seok Bae , Sasha Levin , kvm@vger.kernel.org, Tom Lendacky Subject: Re: [PATCH] x86/entry/64: Disallow RDPID in paranoid entry if KVM is enabled Message-ID: <20200821200207.GW3982@worktop.programming.kicks-ass.net> References: <20200821025050.32573-1-sean.j.christopherson@intel.com> <20200821074743.GB12181@zn.tnic> <3eb94913-662d-5423-21b1-eaf75635142a@redhat.com> <87r1s0gxfj.fsf@nanos.tec.linutronix.de> <5120CF63-12EB-4701-B303-C0A96201F5A2@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5120CF63-12EB-4701-B303-C0A96201F5A2@zytor.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 21, 2020 at 12:55:53PM -0700, hpa@zytor.com wrote: > It is hardly going to be a performance difference for paranoid entry, > which is hopefully rare enough that it falls into the noise. Try perf some day ;-) But yeah, given the utter trainwreck that NMIs are anyway, this is all not going to matter much.