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 X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E423EC3A5A0 for ; Mon, 19 Aug 2019 14:32:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B223020651 for ; Mon, 19 Aug 2019 14:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726820AbfHSOcY (ORCPT ); Mon, 19 Aug 2019 10:32:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41198 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726261AbfHSOcX (ORCPT ); Mon, 19 Aug 2019 10:32:23 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4804A300413D; Mon, 19 Aug 2019 14:32:23 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C58AB1C930; Mon, 19 Aug 2019 14:32:22 +0000 (UTC) From: Jeff Moyer To: Dan Williams Cc: linux-nvdimm , Linux Kernel Mailing List Subject: Re: [PATCH 2/3] libnvdimm/security: Tighten scope of nvdimm->busy vs security operations References: <156583201347.2815870.4687949334637966672.stgit@dwillia2-desk3.amr.corp.intel.com> <156583202386.2815870.16611751329252858110.stgit@dwillia2-desk3.amr.corp.intel.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Mon, 19 Aug 2019 10:32:22 -0400 In-Reply-To: (Dan Williams's message of "Fri, 16 Aug 2019 14:02:19 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Mon, 19 Aug 2019 14:32:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dan Williams writes: > On Fri, Aug 16, 2019 at 1:49 PM Jeff Moyer wrote: >> >> Dan Williams writes: >> >> > The blanket blocking of all security operations while the DIMM is in >> > active use in a region is too restrictive. The only security operations >> > that need to be aware of the ->busy state are those that mutate the >> > state of data, i.e. erase and overwrite. >> > >> > Refactor the ->busy checks to be applied at the entry common entry point >> > in __security_store() rather than each of the helper routines. >> >> I'm not sure this buys you much. Did you test this on actual hardware >> to make sure your assumptions are correct? I guess the worst case is we >> get an "invalid security state" error back from the firmware.... >> >> Still, what's the motivation for this? > > The motivation was when I went to test setting the frozen state and > found that it complained about the DIMM being active. There's nothing > wrong with freezing security while the DIMM is mapped. ...but then I > somehow managed to write this generalized commit message that left out > the explicit failure I was worried about. Yes, moved too fast, but the > motivation is "allow freeze while active" and centralize the ->busy > check so it's just one function to review that common constraint. OK, thanks for the info. Reviewed-by: Jeff Moyer