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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 B754BC433E2 for ; Tue, 23 Mar 2021 16:06:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 829B5619C7 for ; Tue, 23 Mar 2021 16:06:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233088AbhCWQGb (ORCPT ); Tue, 23 Mar 2021 12:06:31 -0400 Received: from mail.skyhub.de ([5.9.137.197]:48220 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233070AbhCWQGH (ORCPT ); Tue, 23 Mar 2021 12:06:07 -0400 Received: from zn.tnic (p200300ec2f0be1003a038ae7f2775171.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:e100:3a03:8ae7:f277:5171]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 28E761EC0473; Tue, 23 Mar 2021 17:06:06 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1616515566; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=48Tq1KSF9gZcQwrvYVZ/vG/u92KavUsXm8/JdQcuEFA=; b=E6+BXLlwX95o8DPfZtqpE5xuogIXh7IFHVRS/iJ5MepQ5UgpS8qeGzvpW2wzXUI3Wv7wVf 9F7NsGzVlj/TfznJN4GIdD8yN0RNP5dQoiasQWwEJVdCYoyp/4n2SXFENQULvxTZpVK2OL tcruxzJ/FdpMsm1q8MHbxO87YVdfTfg= Date: Tue, 23 Mar 2021 17:06:04 +0100 From: Borislav Petkov To: Sean Christopherson Cc: Kai Huang , kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, jarkko@kernel.org, luto@kernel.org, dave.hansen@intel.com, rick.p.edgecombe@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Subject: Re: [PATCH v3 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Message-ID: <20210323160604.GB4729@zn.tnic> References: <062acb801926b2ade2f9fe1672afb7113453a741.1616136308.git.kai.huang@intel.com> <20210322181646.GG6481@zn.tnic> <20210322191540.GH6481@zn.tnic> <20210322210645.GI6481@zn.tnic> <20210323110643.f29e214ebe8ec7a4a3d0bc2e@intel.com> <20210322223726.GJ6481@zn.tnic> <20210323121643.e06403a1bc7819bab7c15d95@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 23, 2021 at 03:45:14PM +0000, Sean Christopherson wrote: > Practically speaking, "basic" deployments of SGX VMs will be insulated from > this bug. KVM doesn't support EPC oversubscription, so even if all EPC is > exhausted, new VMs will fail to launch, but existing VMs will continue to chug > along with no ill effects.... Ok, so it sounds to me like *at* *least* there should be some writeup in Documentation/ explaining to the user what to do when she sees such an EREMOVE failure, perhaps the gist of this thread and then possibly the error message should point to that doc. We will of course have to revisit when this hits the wild and people start (or not) hitting this. But judging by past experience, if it is there, we will hit it. Murphy says so. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette