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 09F66EE7FF4 for ; Mon, 11 Sep 2023 08:41:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4E6F06B0184; Mon, 11 Sep 2023 04:41:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 496806B0187; Mon, 11 Sep 2023 04:41:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 35E316B0188; Mon, 11 Sep 2023 04:41:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 25A056B0184 for ; Mon, 11 Sep 2023 04:41:59 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id F04271408F4 for ; Mon, 11 Sep 2023 08:41:58 +0000 (UTC) X-FDA: 81223673916.10.34E94B2 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by imf25.hostedemail.com (Postfix) with ESMTP id 775D4A001F for ; Mon, 11 Sep 2023 08:41:56 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=juCq8D5H; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf25.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.31) smtp.mailfrom=kirill.shutemov@linux.intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1694421717; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=tOvjKv5Yr9D7BOy953wU4fiaTYWQncTkCMiAEyTizKQ=; b=wUFm+ntJoeO1Wz6srTCBe7DtwsFKOPXkpaJ/sRxkPg1BbLnu/gPRDWXnRo5oEe1wZvjCgU CUNfVQv2jA/09QmYXGrugKm9cWXm/oZNu6ieZ+8SnIh0xOfXlf6Owj8KxS5W1q0U9Wh9Bg dvgEMtS6dsqkScuiKcJ23MHZ4J+zsck= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=juCq8D5H; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf25.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.31) smtp.mailfrom=kirill.shutemov@linux.intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1694421717; a=rsa-sha256; cv=none; b=Z8a/iBkX7EbqsbT7xO6YP50EfI4okwZPF/UHY+AVQXLqeNEiDLDdNdGUiED7oS76jY/uXi ZNThF2sqZGRXWH70NGSPoPZtFOrTLbdAr7sdz8ZBN6ysXjNd2kJEvHrUpoov0cZiO3LSMc wUMG79W9z9sK3HNX4BLRGJlU5VRNU60= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694421716; x=1725957716; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=uhPe1H2Fp1YDVYHUdP69YCF2k7+nQbNT9DvyyBH2lmY=; b=juCq8D5HAATG1lrc1IZpWYckomMzhpD4KvAXP0QDbd+d/92CkfubzshE OEg1OCvNhTfd0kq72oVpyIaJnF4K1PvOT3xKIxHGKLpmzuF5T6QHZ7rou 4l2+LOrUuvQwq9gletzGqEzbcYZFMCtpCRNul05qT9FHImQdtAuK/Rbl7 5IPARk+RiCDWvP0PW0ltEZCrPY2TN6JM05ihcxZC9O4pEyAgVzd3xh3+B H6dd1fmYT0QIMuU+j+f9sZFk8WHKldK4wos9uvrnsHMR6yRZvaVI8nfz/ oekbqJKOceiz8WgKCfhTHXlMeiKYe97285zJOoe1e0flVvGEcX4kFWys3 w==; X-IronPort-AV: E=McAfee;i="6600,9927,10829"; a="442024369" X-IronPort-AV: E=Sophos;i="6.02,243,1688454000"; d="scan'208";a="442024369" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Sep 2023 01:41:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10829"; a="858242359" X-IronPort-AV: E=Sophos;i="6.02,243,1688454000"; d="scan'208";a="858242359" Received: from aabuleil-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.251.216.192]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Sep 2023 01:41:50 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 1DF6310940E; Mon, 11 Sep 2023 11:41:48 +0300 (+03) Date: Mon, 11 Sep 2023 11:41:48 +0300 From: "Kirill A. Shutemov" To: David Hildenbrand Cc: Adrian Hunter , Borislav Petkov , Andrew Morton , 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 Subject: Re: [PATCH 1/3] proc/vmcore: Do not map unaccepted memory Message-ID: <20230911084148.l6han7jxob42rdvm@box.shutemov.name> References: <20230906073902.4229-1-adrian.hunter@intel.com> <20230906073902.4229-2-adrian.hunter@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 775D4A001F X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 6x99oz4bb6j49iujba1mghjp7rtzskku X-HE-Tag: 1694421716-810023 X-HE-Meta: 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 dY7dXsKw Te4u6TOP+Ez1ZQMX+ZdUfEvsk6OavFalY4OThWraZfSKVYUf82hxTVsNjs7FUzj5KejnWVfHXIPaKguYG5MDqk7g6ZYpXr6aHfkUbJHYiTnBy4jPWnlgbvNJURDaVOk81HGNuaShOUr7dQvM= 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 Mon, Sep 11, 2023 at 10:03:36AM +0200, David Hildenbrand wrote: > On 06.09.23 09:39, 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 map unaccepted memory because it can cause the guest to fail. > > > > For /proc/vmcore, which is read-only, this means a read or mmap of > > unaccepted memory will return zeros. > > Does a second (kdump) kernel that exposes /proc/vmcore reliably get access > to the information whether memory of the first kernel is unaccepted (IOW, > not its memory, but the memory of the first kernel it is supposed to expose > via /proc/vmcore)? There are few patches in my queue to few related issue, but generally, yes, the information is available to the target kernel via EFI configuration table. -- Kiryl Shutsemau / Kirill A. Shutemov