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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9D48C433F5 for ; Fri, 4 Mar 2022 15:23:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237223AbiCDPYY (ORCPT ); Fri, 4 Mar 2022 10:24:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235995AbiCDPYY (ORCPT ); Fri, 4 Mar 2022 10:24:24 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D12FC13CEC8; Fri, 4 Mar 2022 07:23:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646407416; x=1677943416; h=message-id:date:mime-version:to:cc:references:from: subject:in-reply-to:content-transfer-encoding; bh=8+CEXWwRwOMrbbF77tgElxSqFXtFdC2qH4kdmgKvO/8=; b=Ku2PX1M7qTskpAJoDfaZfr44hYgwjmKLKSxPUiaMNC6RKTBTpgK1Ybbv hjLNPXHdADnx24V3yH6fkiNiwLr36m723Q/khAKiOnaUuk+CyvbwFDdTD FPwx5W3Bmw/9Q9RrJMkP/TfladthCf40q3UJ1/tAL5kyYWt4Qc40SEWBA DBNxeIBj3fzZT+/w85PNIsfpGN1C1FEyW0XxEarqeFJpYFMiWjtX+VXqj DJUnw2Na35dgNqhbVBX/WjubWXDXjezcy9i3yLLUfEIskSr2D2SXLuDww LELWe4Js0Q2hrWLkQv/TSfW/KEi/byuJZBQVc5Ikm71v/0XkmUchFt2Bu Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10276"; a="241417941" X-IronPort-AV: E=Sophos;i="5.90,155,1643702400"; d="scan'208";a="241417941" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Mar 2022 07:23:36 -0800 X-IronPort-AV: E=Sophos;i="5.90,155,1643702400"; d="scan'208";a="640610291" Received: from eabada-mobl2.amr.corp.intel.com (HELO [10.209.6.252]) ([10.209.6.252]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Mar 2022 07:23:34 -0800 Message-ID: Date: Fri, 4 Mar 2022 07:23:28 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Content-Language: en-US To: Brijesh Singh , x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org Cc: Thomas Gleixner , Ingo Molnar , Joerg Roedel , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Borislav Petkov , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , "Dr . David Alan Gilbert" , brijesh.ksingh@gmail.com, tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com References: <20220224165625.2175020-1-brijesh.singh@amd.com> <20220224165625.2175020-43-brijesh.singh@amd.com> <9c075b36-e450-831b-0ae2-3b680686beb4@amd.com> From: Dave Hansen Subject: Re: [PATCH v11 42/45] virt: Add SEV-SNP guest driver In-Reply-To: <9c075b36-e450-831b-0ae2-3b680686beb4@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On 3/4/22 05:17, Brijesh Singh wrote: >> BTW, this look like a generic allocator thingy. But it's only ever used >> to allocate a 'struct snp_guest_msg'. Why all the trouble to allocate >> and free one fixed-size structure? The changelog and comments don't >> shed any light. > The GHCB specification says that a guest must use shared memory for > request, response, and certificate blob. In this patch, you are seeing > that {alloc,free}_shared_pages() used only to alloc/free the request and > response page. In the last patch, we used the same generic function to > allocate the certificate blob with a different size (~16K) than 'struct > snp_guest_msg.' It sounds like it's worth a sentence or two in the changelog to explain this new "allocator" and its future uses.