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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 8C6FFC433E8 for ; Wed, 15 Jul 2020 10:57:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60479206F5 for ; Wed, 15 Jul 2020 10:57:13 +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="BGOcXPSi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729699AbgGOK5K (ORCPT ); Wed, 15 Jul 2020 06:57:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726201AbgGOK5K (ORCPT ); Wed, 15 Jul 2020 06:57:10 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6200C061755; Wed, 15 Jul 2020 03:57:09 -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=K8h4KI86Mzb6BYGGyc/D5d7vo4fVAFqxYqHc3CALsmU=; b=BGOcXPSin+HC2fF1VqIS2IqzXw YGPNLIs6u0i4juJ6jLImClXgjkl/hxvLhGvj1eiIwTuEcj2kgDhn5u6DM88nmQDKbFGgiCcgyySpw gParcOSrVYvhyiZNKOn+DfeACZ9Ocs9TrRzsRLcdRCSbsWrIdTBx760Ir3sQ8gWmYlxLt0/+sxfVx xxVGGbbbEmmWZBphVSBO7n8aI+TQanyTc0mG+sXVGwxO2ubsUUdrGKoi+fVxeddBO1jINLWyEN1oh TbLk/A4GJCz6hdj/J7aX87Yc7dq8bkDqmHIJpZx96V571lVNVCldLVdBsHS0jFDf2l7fkWXQZ7K9g XGLSiGaw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jvf5V-0006Ya-Er; Wed, 15 Jul 2020 10:56:37 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id B5DEA300446; Wed, 15 Jul 2020 12:56:29 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A5F9C203A6143; Wed, 15 Jul 2020 12:56:29 +0200 (CEST) Date: Wed, 15 Jul 2020 12:56:29 +0200 From: Peter Zijlstra To: Joerg Roedel Cc: Joerg Roedel , x86@kernel.org, hpa@zytor.com, Andy Lutomirski , Dave Hansen , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v4 45/75] x86/sev-es: Adjust #VC IST Stack on entering NMI handler Message-ID: <20200715105629.GK10769@hirez.programming.kicks-ass.net> References: <20200714120917.11253-1-joro@8bytes.org> <20200714120917.11253-46-joro@8bytes.org> <20200715094702.GF10769@hirez.programming.kicks-ass.net> <20200715102653.GN16200@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200715102653.GN16200@suse.de> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Jul 15, 2020 at 12:26:53PM +0200, Joerg Roedel wrote: > On Wed, Jul 15, 2020 at 11:47:02AM +0200, Peter Zijlstra wrote: > > That's pretty disguisting :-( > > Yeah, but its needed because ... IST :( > I am open for suggestions on how to make it less disgusting. Or maybe > you like it more if you think of it as a software implementation of what > hardware should actually do to make IST less painful. No bright ideas, sadly..