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 52A6AC4332F for ; Wed, 12 Jan 2022 19:35:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D587C6B0208; Wed, 12 Jan 2022 14:35:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D075A6B0209; Wed, 12 Jan 2022 14:35:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BA8C86B020A; Wed, 12 Jan 2022 14:35:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0046.hostedemail.com [216.40.44.46]) by kanga.kvack.org (Postfix) with ESMTP id 965DD6B0208 for ; Wed, 12 Jan 2022 14:35:29 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 3676D181CAC7B for ; Wed, 12 Jan 2022 19:35:29 +0000 (UTC) X-FDA: 79022639178.17.CC4F437 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by imf06.hostedemail.com (Postfix) with ESMTP id 93D45180009 for ; Wed, 12 Jan 2022 19:35:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642016128; x=1673552128; h=to:cc:references:from:subject:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=YuJU8sDPPXrY7j14l/N36i5HlcFv+BrkOxyMAgWnQeU=; b=j5T1yJYXHBaXcYPAkLRlGIFwfNWlphC5K/PlchsbkjmuANw5/xZPKMKH kiEJChBjSXYbxsnUmZZXQ1dCF1TbpwOiqOCRcwPYDj6XrQe6bCWw/NLG+ 32Qmxfv5mkkCUVfr4oMq5duJDT92yVY1poP4BmhyoWIn3ZZuoPLgTKxTE CGb8s3in85I1D18VrBIuWhKJ6VLogBspg6Rx0D0FiEdIu6vSJefQ1VF1O kqwYAo5YmmlFMpYqvr0hcIK7qVW7utekxJrKJYGIXviTN7CSOUjU2Dypq TKSSrJ0fPA6DulKUZiIc73YAnnYpXez+tbV2FJtgz+N2cD/4qYT814iN6 g==; X-IronPort-AV: E=McAfee;i="6200,9189,10225"; a="268185037" X-IronPort-AV: E=Sophos;i="5.88,282,1635231600"; d="scan'208";a="268185037" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 11:35:27 -0800 X-IronPort-AV: E=Sophos;i="5.88,282,1635231600"; d="scan'208";a="593118453" Received: from kumarkan-mobl.amr.corp.intel.com (HELO [10.209.80.194]) ([10.209.80.194]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 11:35:25 -0800 To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Borislav Petkov , Andy Lutomirski , Sean Christopherson , Andrew Morton , Joerg Roedel , Ard Biesheuvel , Andi Kleen , Kuppuswamy Sathyanarayanan , David Rientjes , Vlastimil Babka , Tom Lendacky , Thomas Gleixner , Peter Zijlstra , Paolo Bonzini , Ingo Molnar , Varad Gautam , Dario Faggioli , x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220111113314.27173-1-kirill.shutemov@linux.intel.com> <20220111113314.27173-4-kirill.shutemov@linux.intel.com> <20220112192955.amelr4sq662pfv67@box.shutemov.name> From: Dave Hansen Subject: Re: [PATCHv2 3/7] efi/x86: Implement support for unaccepted memory Message-ID: <5e624c5a-387e-fef0-3870-f6a58d3f832e@intel.com> Date: Wed, 12 Jan 2022 11:35:23 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20220112192955.amelr4sq662pfv67@box.shutemov.name> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 93D45180009 X-Stat-Signature: bu9c7fqidozr9ogxuxm8skdqmbs84afo Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=j5T1yJYX; spf=none (imf06.hostedemail.com: domain of dave.hansen@intel.com has no SPF policy when checking 192.55.52.88) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com X-HE-Tag: 1642016128-332699 Content-Transfer-Encoding: quoted-printable 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 1/12/22 11:29 AM, Kirill A. Shutemov wrote: >>> + * In the worst case scenario -- a huge hole in the middle of the >>> + * address space -- It needs 256MiB to handle 4PiB of the address >>> + * space. >>> + * >>> + * TODO: handle situation if params->unaccepted_memory has already = set. >>> + * It's required to deal with kexec. >> What happens today with kexec() since its not dealt with? > I didn't give it a try, but I assume it will hang. >=20 > There are more things to do to make kexec working and safe. We will get > there, but it is not top priority. Well, if we know it's broken, shouldn't we at least turn kexec off? It would be dirt simple to do in Kconfig. As would setting: kexec_load_disabled =3D true; which would probably also do the trick. That's from three seconds of looking. I'm sure you can come up with something better.