From: PrasannaKumar Muralidharan Subject: Re: [tpmdd-devel] [PATCH] tpm: remove chip_num parameter from in-kernel API Date: Tue, 24 Oct 2017 23:14:32 +0530 Message-ID: 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> <20171024173757.GA1806@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Dmitry Torokhov , 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 , To: Jason Gunthorpe Return-path: Received: from mail-io0-f195.google.com ([209.85.223.195]:51330 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751316AbdJXRod (ORCPT ); Tue, 24 Oct 2017 13:44:33 -0400 In-Reply-To: <20171024173757.GA1806@obsidianresearch.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: On 24 October 2017 at 23:07, Jason Gunthorpe wrote: > 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? I tried to do that via the rfc we discussed previously. It may not be the right way but I wanted to start the discussion via the rfc. Thanks, PrasannaKumar