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=-3.6 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 1D38FC433DB for ; Tue, 16 Feb 2021 14:47:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4C67B64E10 for ; Tue, 16 Feb 2021 14:47:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C67B64E10 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B816E6B0005; Tue, 16 Feb 2021 09:47:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B0A546B0006; Tue, 16 Feb 2021 09:47:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9AC606B006C; Tue, 16 Feb 2021 09:47:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0194.hostedemail.com [216.40.44.194]) by kanga.kvack.org (Postfix) with ESMTP id 7EA776B0005 for ; Tue, 16 Feb 2021 09:47:31 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 374BD824805A for ; Tue, 16 Feb 2021 14:47:31 +0000 (UTC) X-FDA: 77824409502.17.5B01838 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf08.hostedemail.com (Postfix) with ESMTP id 4E7C580192C7 for ; Tue, 16 Feb 2021 14:47:24 +0000 (UTC) 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=bxlTiNMXwWvTpGUCzU5ugE7Frn3orOldF9qoZ5yF6PI=; b=EWX4eShJ6iAHpb0hbxQG2LodSD Ay9cuFMKd17JmETbFV7MLpjTHWZc3kQAhCTxbAtDSdyT7ovgWNA2UoJH8zurXRfadm/vEP/LT5SJu 2ZXnNbQ6Yr//Q3OQlKLN0TE8bSXTQItacDyRgwV8t3xQ76KJoGy8vaUEMRNCfZEsEZzFB/cM/lF0c gSl7zmvWnI8jQ13SRsxrBMKvoZ9HfUVuhRFqpkrPDXRpJTeA3bELR815CUPKFid0Ob2MNfc/Fb54T Nak5oWhn9/PIGcB0rb+WrZ0KbOG8CQQ2nCij7RPVq2pemk621ugr8AchqD9FZp+heerPb0HuGYwYM g+E8D+Gg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lC1cd-00GyCj-5u; Tue, 16 Feb 2021 14:46:48 +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 496DF3007CD; Tue, 16 Feb 2021 15:46:36 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 38B292BC49497; Tue, 16 Feb 2021 15:46:36 +0100 (CET) Date: Tue, 16 Feb 2021 15:46:36 +0100 From: Peter Zijlstra To: Andi Kleen Cc: Joerg Roedel , David Rientjes , Borislav Petkov , Andy Lutomirski , Sean Christopherson , Andrew Morton , "Kirill A. Shutemov" , Brijesh Singh , Tom Lendacky , Jon Grimm , Thomas Gleixner , Christoph Hellwig , Paolo Bonzini , Ingo Molnar , x86@kernel.org, linux-mm@kvack.org Subject: Re: AMD SEV-SNP/Intel TDX: validation of memory pages Message-ID: References: <20210212131907.GI5453@suse.de> <20210212145318.GK5453@suse.de> <20210212152813.GA28884@suse.de> <20210212161849.GB28884@suse.de> <20210216100045.GE28884@suse.de> <20210216142741.GI365765@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210216142741.GI365765@tassilo.jf.intel.com> X-Stat-Signature: tbrpc8zingtfs93xir57q1cpwqwg3sph X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 4E7C580192C7 Received-SPF: none (infradead.org>: No applicable sender policy available) receiver=imf08; identity=mailfrom; envelope-from=""; helo=casper.infradead.org; client-ip=90.155.50.34 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1613486844-158220 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Feb 16, 2021 at 06:27:41AM -0800, Andi Kleen wrote: > I think the IST solution should at least be explored before > dismissing it. It might be simpler than anything else (like > using new APIs) Have you seen the trainwreck bonzini proposed? The very simplest thing is saying no to TDX. That 'solution' also hard relies on #VE not nesting more than once, so lovely things like: #VE -> #DB -> #VE -> #NMI -> #VE, or #VE -> NMI -> #VE -> #MC -> #VE or any number of other possible 'fun' combinations _must_ not happen. And yes, I know #MC isn't supported just now, but the above would mandate it never be supported _ever_, because otherwise the IST hack crumbles. Again, repeat after me: ISTs are a part of the problem. So how about fixing TDX instead of forcing us to do horrible fragile things we all know will end up in tears?