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 C6C96C4332F for ; Fri, 4 Mar 2022 15:23:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 33B288D0002; Fri, 4 Mar 2022 10:23:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2EABA8D0001; Fri, 4 Mar 2022 10:23:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1B28B8D0002; Fri, 4 Mar 2022 10:23:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0242.hostedemail.com [216.40.44.242]) by kanga.kvack.org (Postfix) with ESMTP id 0B7BD8D0001 for ; Fri, 4 Mar 2022 10:23:39 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id C1A09180F1E65 for ; Fri, 4 Mar 2022 15:23:38 +0000 (UTC) X-FDA: 79207073316.24.C22F1F4 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf02.hostedemail.com (Postfix) with ESMTP id 12AD780028 for ; Fri, 4 Mar 2022 15:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646407418; x=1677943418; h=message-id:date:mime-version:to:cc:references:from: subject:in-reply-to:content-transfer-encoding; bh=8+CEXWwRwOMrbbF77tgElxSqFXtFdC2qH4kdmgKvO/8=; b=Va8zyO9zC5O9/bMgVx93nesQxY5PaFOEZcrCuMMx7LiwQqDYmj8xOxy4 /oMamq+He6Z0FvSD7xAWaxhxW2/EYFQ2TI/RDfYknSdvrs7k6YpzEzMUK 9lXoh1/1vo5ne46e2CmGe2oMO9+xNDpS4Iba/urrIGnNqsxnR9kO/zxfN nuCiyfx7vTJW7KIqLCIasFXUQd3kQS27/lvO4ZjM0JDAb62wg0rVEI0Lw Y/6m+a/qileO+t+CraNdECT9rUkGth4ufDGq9ZmnbYjL257dflZYb1uj5 CV1gwNQPy62EeF3DMQQcVzg6W9QxXnazdW52SrVmo0QObOpLEmSbJlhAu Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10276"; a="340426095" X-IronPort-AV: E=Sophos;i="5.90,155,1643702400"; d="scan'208";a="340426095" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.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 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 12AD780028 X-Stat-Signature: kkt8hs1b3jouba3mbwnkn8iayzguqsz4 Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Va8zyO9z; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf02.hostedemail.com: domain of dave.hansen@intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=dave.hansen@intel.com X-HE-Tag: 1646407417-275132 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 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.