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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1172CA0ECE for ; Tue, 12 Sep 2023 07:50:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5A21C6B00A8; Tue, 12 Sep 2023 03:50:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 552596B00B0; Tue, 12 Sep 2023 03:50:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 41BB66B00BA; Tue, 12 Sep 2023 03:50:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 2EFF86B00A8 for ; Tue, 12 Sep 2023 03:50:28 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 07B5E160D3F for ; Tue, 12 Sep 2023 07:50:28 +0000 (UTC) X-FDA: 81227172936.03.5639FA9 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf07.hostedemail.com (Postfix) with ESMTP id BA6AC4000C for ; Tue, 12 Sep 2023 07:50:25 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=B+vLAeVQ; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf07.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1694505025; h=from:from:sender: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/mzVy3Mc/7bAQAhf4c1iHjdctfZReLCkKlOdBdE9Gi0=; b=xX2qUowOHQA4++oUPwneEt0CZUYAFwdf4Wl4GNLXr6UkzG+IB/ZlSgp6oF33zfduMxJlZJ 4xF6hWjqZpEun6WU4L7hJ33qgQbqUWH84yWNpwhAqA59Q7JPmXhsGpJFe5UPu/nmBDuEGP 8mrXyDO7Q+OJ6/yGrTq+yCA8FVpfKrA= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=B+vLAeVQ; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf07.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1694505025; a=rsa-sha256; cv=none; b=OYE2bBBbZGG15mjYEuY0ez2cQ4D3T4FxrGLJ3hUpksX+EnCYjiqUfJEgnd1fG1JhMvB1t9 l3X1yfYLo2Fx3UVIhOOOpYcCi9mgIwjMeqzh/VsW05S9WcBgHf3D2hVRlzHGcLQkAf4TDJ HRbN4vz+6+kNdZ552Brku9UOrIFu/Kg= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694505025; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/mzVy3Mc/7bAQAhf4c1iHjdctfZReLCkKlOdBdE9Gi0=; b=B+vLAeVQoVDymVlPsPnV/wfcQYq9Bkif6CIzpDhyCzbKlqG/AqhhtcrIpwbYvMRetdU85Q 2JyxaYgQMd+++6Sd7bCCezYId9CZWcsqgqXA20kHcukJR7EW6XTbQg+0PmGULn5Tcyx3UQ 1LZwF4BU+0SlyXEMC3MgIF8SZOGiaoA= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-606-XKQB4w3oMQGPqbOfYzBxOw-1; Tue, 12 Sep 2023 03:50:21 -0400 X-MC-Unique: XKQB4w3oMQGPqbOfYzBxOw-1 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-401dba99384so40520655e9.3 for ; Tue, 12 Sep 2023 00:50:20 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694505020; x=1695109820; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=/mzVy3Mc/7bAQAhf4c1iHjdctfZReLCkKlOdBdE9Gi0=; b=XJH9mBIrKoAbKvysaqDqnRbrDn1xF/LxNkowe9se3XGtxEy6Ylpuc34rz89dBOpX9B dvN0UnWhm0yYeXB2fx1STRGq3lComPbEFnFAhRBtZ4k6vXUu070WxLV87ATuTGIinOQf d1uvEwKX1VFOO2SYYcopksPgifZdI12888JChTIVfMJimGUZ4TLAyc77szmh5ZzlQdi5 WZ0jCP71+WMzfUugWhAQ5mBy/Ybdy/6rvFPer+8zPZ5ddyglaZnKfOkcck08Gu2Xf6ao vEGcb89SwLvvpy5314yauUqFdjxzSujTNtU3i+CnkQfoJc06E7Q5EbCaV+zgbLM42G/R vJQA== X-Gm-Message-State: AOJu0Yy5Opi6ven/hXqot1Ayj03l36xCATBcjm3oayFyYKi2veOKA4NA cLjVEW6Aahy9z1CzcKYGlm+fzrNvzbOkOtSh5uanOJPOu5DSNGQJyQ3NnSn4J1voZlPeAz/tu6R 1YC8sh/KWUIM= X-Received: by 2002:a05:600c:b59:b0:402:8896:bb7b with SMTP id k25-20020a05600c0b5900b004028896bb7bmr10597660wmr.6.1694505020035; Tue, 12 Sep 2023 00:50:20 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEWb5KPPue011J3X0eD1sW7gLSQXGBULtIBQ0OCAIfXnbwUsDGLY2yVip/HeBg+JEeYAy53ww== X-Received: by 2002:a05:600c:b59:b0:402:8896:bb7b with SMTP id k25-20020a05600c0b5900b004028896bb7bmr10597627wmr.6.1694505019623; Tue, 12 Sep 2023 00:50:19 -0700 (PDT) Received: from ?IPV6:2003:cb:c74f:d600:c705:bc25:17b2:71c9? (p200300cbc74fd600c705bc2517b271c9.dip0.t-ipconnect.de. [2003:cb:c74f:d600:c705:bc25:17b2:71c9]) by smtp.gmail.com with ESMTPSA id ay7-20020a05600c1e0700b0040303a9965asm9212894wmb.40.2023.09.12.00.50.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 Sep 2023 00:50:19 -0700 (PDT) Message-ID: Date: Tue, 12 Sep 2023 09:50:18 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH V2 1/2] efi/unaccepted: Do not let /proc/vmcore try to access unaccepted memory To: Adrian Hunter , "Kirill A. Shutemov" , Borislav Petkov , Andrew Morton , Ard Biesheuvel Cc: Dave Hansen , Vlastimil Babka , Mike Rapoport , Lorenzo Stoakes , Tom Lendacky , Baoquan He , Vivek Goyal , Dave Young , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, kexec@lists.infradead.org References: <20230911112114.91323-1-adrian.hunter@intel.com> <20230911112114.91323-2-adrian.hunter@intel.com> <96f124d6-c1f2-adb3-1d3b-8329e85ff099@redhat.com> <1c736ca3-36e2-3225-2f98-e51149c468ef@intel.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <1c736ca3-36e2-3225-2f98-e51149c468ef@intel.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: BA6AC4000C X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 89bae3bednjq5npiw9ueifjcr1r5wneq X-HE-Tag: 1694505025-708403 X-HE-Meta: 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 YNOx+N5K 2AaMMb26tRZFCR1NOnIarl0PL59gD2m7c5PYb+Jk0Ma2I6wNQ/jcU9tbLAieJWagG5z72r9sLfkUPd5USD5nc3eAtfoVB99E3S3/wIJjuuMPOL6IMwVVIKTWgLJi2h3YYWO4Mypa1PWRhSw+Q4ZiaNwcNPl1p9Dsed7FfQxMcjwjkBENurE1BhggIRMTTDpRt6uhRzSpQdtEcD6jriuhxgYV92IcMHv28Za2uwXvNl1e7aCWSXZM1G8SBtlUSVykFO5Hkh8mO4/XVVqWBUv4ZqyuQdpPYciW2KGmAezSPQ+K1AINBUNVv6/lQmVquXTDuuMJHYczAhmZ8sjWNLq6EuohUNSJp0/cX8GpNSen5XlvWwr1KbGJEA5Lhn1rbMoNdnuFo/SWlKm2+0ObgHguCt7Rc0i/Repw1AJvc0fT+1WGC5xdjnTs+8f5m6w== 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 12.09.23 09:47, Adrian Hunter wrote: > On 12/09/23 10:19, David Hildenbrand wrote: >> On 11.09.23 13:21, Adrian Hunter wrote: >>> Support for unaccepted memory was added recently, refer commit dcdfdd40fa82 >>> ("mm: Add support for unaccepted memory"), whereby a virtual machine may >>> need to accept memory before it can be used. >>> >>> Do not let /proc/vmcore try to access unaccepted memory because it can >>> cause the guest to fail. >> >> Oh, hold on. What are the actual side effects of this? >> >> Once we're in the kdump kernel, any guest is already dead. So failing a guest doesn't apply, no? >> > Unaccepted Memory is used by virtual machines. In this case the guest > has kexec'ed to a dump-capture kernel, so the virtual machine is still > alive and running the dump-capture kernel. Ah, I got lost in TDX host semantics. So what you're saying, if we (guest) are reading unnaccepted memory we will get zapped. Makes sense. -- Cheers, David / dhildenb