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=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 B4E03C31E4B for ; Fri, 14 Jun 2019 13:34:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A94F20851 for ; Fri, 14 Jun 2019 13:34:06 +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="RqOZRS7u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728108AbfFNNeF (ORCPT ); Fri, 14 Jun 2019 09:34:05 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38994 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727842AbfFNNeE (ORCPT ); Fri, 14 Jun 2019 09:34:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=C0nBHLDkMzGog27NgS5rehy1Wv/08uCW/YzQiNw7nNs=; b=RqOZRS7urkSMLctNG2/1Ak12G f/4kQHDb+UbN4+940BDAXkw1woJik4UQ0ENEMnpn29ly5gI/CXJdX+l08QcStbFkmC0zMpWNGjc4C WEk5rb584twn+em5U7jBNkLRnOLXdnSoKmJzLWr5MOv/hEv/jGeWsDCFM4fe0ZKCQPzAMmm2+DDAa HwPEfLEaIUktNrPdwIKJ4a6E58LjOYEDRRGDcxDDJpiH9chmHcjMMzS7cfxAacSXSzFrdBbDhteHl GfdnjQgCFpUYAhbI88l+XnPm8iSKqpuDlMnxBcMLo5SMoBRwmD7NLqJJtqQBtdQRQBPcp5J+DrcXR TkIwqv4fw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hbmL2-00082H-Eq; Fri, 14 Jun 2019 13:33:52 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id EAAE520A3149A; Fri, 14 Jun 2019 15:33:50 +0200 (CEST) Date: Fri, 14 Jun 2019 15:33:50 +0200 From: Peter Zijlstra To: Jiri Olsa Cc: Kan Liang , Jiri Olsa , David Carrillo-Cisneros , Arnaldo Carvalho de Melo , lkml , Ingo Molnar , Namhyung Kim , Alexander Shishkin , Andi Kleen , Tom Vaden Subject: Re: [RFC] perf/x86/intel: Disable check_msr for real hw Message-ID: <20190614133350.GT3436@hirez.programming.kicks-ass.net> References: <20190614112853.GC4325@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190614112853.GC4325@krava> 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, Jun 14, 2019 at 01:28:53PM +0200, Jiri Olsa wrote: > hi, > the HPE server can do POST tracing and have enabled LBR > tracing during the boot, which makes check_msr fail falsly. > > It looks like check_msr code was added only to check on guests > MSR access, would it be then ok to disable check_msr for real > hardware? (as in patch below) > > We could also check if LBR tracing is enabled and make > appropriate checks, but this change is simpler ;-) > > ideas? thanks, > jirka > > > --- > arch/x86/events/intel/core.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c > index 71001f005bfe..1194ae7e1992 100644 > --- a/arch/x86/events/intel/core.c > +++ b/arch/x86/events/intel/core.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > #include "../perf_event.h" > > @@ -4050,6 +4051,13 @@ static bool check_msr(unsigned long msr, u64 mask) > { > u64 val_old, val_new, val_tmp; > > + /* > + * Disable the check for real HW, so we don't > + * mess up with potentionaly enabled regs. > + */ > + if (hypervisor_is_type(X86_HYPER_NATIVE)) > + return true; Yeah, I think that works, or !boot_cpu_has(X86_FEATURE_HYPERVISOR). > /* > * Read the current value, change it and read it back to see if it > * matches, this is needed to detect certain hardware emulators > -- > 2.21.0 >