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 11565C04EB5 for ; Wed, 20 Sep 2023 18:08:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229644AbjITSI5 (ORCPT ); Wed, 20 Sep 2023 14:08:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229617AbjITSIz (ORCPT ); Wed, 20 Sep 2023 14:08:55 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C770EB9 for ; Wed, 20 Sep 2023 11:08:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695233329; x=1726769329; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=+v3bN4jZAuS5dnJ4c3CbLpISfxHCdKuf8qMN+4iFJNg=; b=k1MtCZwwXsW/mOuF1ySe4tzMP8LxghkoiTC1Ty5Lq0lJQDHdOJFwN5oL eOKALLjhLWNBdE1IU6fqNVMM+On1vzrcMo7V7BL3LQfyu6pD3ma5B7OCF uvfU8F0Ep33Dbh01s6/NWu816nBFsMgPLA76uPiNlFaqkl9DgPcC7wTa5 0iwOQiclXAXZdj1p1dT1rhCKf5lI2ZZK0ICpmBjI8fvqWeyIcPbkvvt+U k9RElm4pWpI6F0zDvqRm/aqYQPgTSKHNCCZlw2gHtiuAV25DVOrBRFaGb L4ghSTv7esmDH3jKr0gv1sUpwRpnA+DWLbypqvq1KeHikVpJsEpGltM2/ g==; X-IronPort-AV: E=McAfee;i="6600,9927,10839"; a="359684993" X-IronPort-AV: E=Sophos;i="6.03,162,1694761200"; d="scan'208";a="359684993" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Sep 2023 11:08:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10839"; a="993713790" X-IronPort-AV: E=Sophos;i="6.03,162,1694761200"; d="scan'208";a="993713790" Received: from pkmanna-mobl3.amr.corp.intel.com (HELO [10.209.53.192]) ([10.209.53.192]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Sep 2023 11:08:48 -0700 Message-ID: Date: Wed, 20 Sep 2023 11:08:49 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] virt: tdx-guest: Add Quote generation support using TSM_REPORTS Content-Language: en-US To: "Kirill A . Shutemov" Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Dan Williams , "H . Peter Anvin" , Tony Luck , Wander Lairson Costa , Erdem Aktas , Dionna Amalie Glaze , Qinkun Bao , Guorui Yu , linux-coco@lists.linux.dev, x86@kernel.org, linux-kernel@vger.kernel.org References: <20230914031349.23516-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20230920131633.ig6ldmwavpu7uhss@box.shutemov.name> <0031e031-10a8-43b1-a29c-8e1cf913eaad@linux.intel.com> <20230920175248.6foe67cwfe5oaa7u@box.shutemov.name> From: Kuppuswamy Sathyanarayanan In-Reply-To: <20230920175248.6foe67cwfe5oaa7u@box.shutemov.name> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/20/2023 10:52 AM, Kirill A . Shutemov wrote: > On Wed, Sep 20, 2023 at 08:27:39AM -0700, Kuppuswamy Sathyanarayanan wrote: >> >> >> On 9/20/2023 6:16 AM, Kirill A . Shutemov wrote: >>>> +static u8 *tdx_report_new(const struct tsm_desc *desc, void *data, size_t *outblob_len) >>>> +{ >>>> + struct tdx_quote_buf *quote_buf = quote_data; >>>> + int ret; >>>> + u8 *buf; >>>> + u64 err; >>>> + >>>> + if (mutex_lock_interruptible("e_lock)) >>>> + return ERR_PTR(-EINTR); >>>> + >>>> + /* >>>> + * If the previous request is timedout or interrupted, and the >>>> + * Quote buf status is still in GET_QUOTE_IN_FLIGHT (owned by >>>> + * VMM), don't permit any new request. >>>> + */ >>>> + if (quote_buf->status == GET_QUOTE_IN_FLIGHT) { >>>> + ret = -EBUSY; >>>> + goto done; >>>> + } >>>> + >>>> + if (desc->inblob_len != TDX_REPORTDATA_LEN) { >>>> + ret = -EINVAL; >>>> + goto done; >>>> + } >>>> + >>>> + /* TDX attestation only supports default format request */ >>>> + if (desc->outblob_format != TSM_FORMAT_DEFAULT) { >>>> + ret = -EINVAL; >>>> + goto done; >>>> + } >>>> + >>>> + u8 *reportdata __free(kfree) = kmalloc(TDX_REPORTDATA_LEN, GFP_KERNEL); >>> __free() is new to me. Good to know. >>> >>> But are we okay now with declaring variables in the middle of the >>> function? Any reason we can't do at the top? >> >> Declaring variables at the top is no longer a hard requirement. The main reason >> for declaring it here is to use __free cleanup function. If we use top >> declaration, then we have free it manually. > > What's wrong with allocating it it there too? My thinking is to allocate it when we really need it. We only need this memory if the GetQuote hypercall is successful. We can also allocate it at the top and there is nothing wrong with it, but it will not be used in failure cases. Since top declarations are not a requirement, why allocate it early? > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer