From: Jason Gunthorpe Subject: Re: [tpmdd-devel] [PATCH] tpm: remove chip_num parameter from in-kernel API Date: Tue, 24 Oct 2017 11:37:57 -0600 Message-ID: <20171024173757.GA1806@obsidianresearch.com> References: <20171023123817.18559-1-jarkko.sakkinen@linux.intel.com> <20171023163139.GA17394@obsidianresearch.com> <20171024154440.3jeupmus43jcgbbz@linux.intel.com> <20171024155526.GA32250@obsidianresearch.com> <20171024161118.GA348@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: PrasannaKumar Muralidharan , Jarkko Sakkinen , Stefan Berger , linux-integrity@vger.kernel.org, David Howells , Herbert Xu , "open list:INTEGRITY MEASUREMENT ARCHITECTURE IMA" , Dmitry Kasatkin , open list , linux-security-module@vger.kernel.org, "moderated list:TPM DEVICE DRIVER" , "open list:KEYS-TRUSTED" , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , James Morris , Matt Mackall Return-path: Received: from quartz.orcorp.ca ([184.70.90.242]:33314 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751316AbdJXRiI (ORCPT ); Tue, 24 Oct 2017 13:38:08 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-crypto-owner@vger.kernel.org List-ID: On Tue, Oct 24, 2017 at 10:02:00AM -0700, Dmitry Torokhov wrote: > tpm-rng is abomination that should be kicked out as soon as possible. > It wrecks havoc with the power management (TPM chip drivers may go > into suspend state, but tpm_rng does not do any power management and > happily forwards requests to suspended hardware) and may be available > when there is no TPM at all yet (the drivers have not been probed yet, > or have gotten a deferral, etc). Makes sense > TPM core should register HWRNGs when chips are ready. The main thing I've wanted from the TPM RNG is 'add_early_randomness'.. We can certainly provide a TPM interface to hwrng, it seems reasonable. Excep that we already have a user api in /dev/tpm to access the tpm RNG, is the duplication a problem? Jason