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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 D076FC43381 for ; Fri, 22 Feb 2019 22:07:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AAC0A2075C for ; Fri, 22 Feb 2019 22:07:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726428AbfBVWHY (ORCPT ); Fri, 22 Feb 2019 17:07:24 -0500 Received: from mail-qt1-f196.google.com ([209.85.160.196]:40669 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbfBVWHY (ORCPT ); Fri, 22 Feb 2019 17:07:24 -0500 Received: by mail-qt1-f196.google.com with SMTP id j36so4302379qta.7 for ; Fri, 22 Feb 2019 14:07:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=WVlgmnFkcj2PmgtNeWcNciyK5dvnSRfqqMGJ0Dku9LQ=; b=lW44EhE5OUsSYpSIin5Y+YeKEq4mWNeNk16/HPfZQLCBVsDiDdTcwh0NdMuhlwad+z mTGOs3/LWJI6jZEVQ3d4/pRYWgSWA3ghBkMZ6jwIuzwwMB2FQEKbikCtJFxr/I/STRHu rzXGBmBk1T4//CTrI4o0eVPw/sg/1F624IvGL8eZfx4x0uUMl5VdyiyR9ZNq3Oa1IMsw TM2DWMRxeNTEO9YxuhGS51PupdxIr/Gh7oRLdul1Gzy0/BmJE1NYVPSZmkSpgX/GBnxr RSStDbJ0giTDcwX7+JByDQda3466VOA+fFWHMBkQKIXHimylIqBrUS+nen1zuJElaxWA SP8g== X-Gm-Message-State: AHQUAubqoUskgUXype1w8N99uBdBDste/aTIBHiWyQo5gUuPnto0oAHf U8z6sBDj9AkHYNb7Ia6H3h+XQa+H/l1HRQ== X-Google-Smtp-Source: AHgI3IYvHiFjrOAzBgT1znlmxVrxI9W0OFavXYsgR9argZGwvDKiuaeZWSbeIcraDzjjIn6cgCSCmA== X-Received: by 2002:ac8:346c:: with SMTP id v41mr4832346qtb.231.1550873242849; Fri, 22 Feb 2019 14:07:22 -0800 (PST) Received: from redhat.com (pool-173-76-246-42.bstnma.fios.verizon.net. [173.76.246.42]) by smtp.gmail.com with ESMTPSA id i33sm2105898qti.74.2019.02.22.14.07.21 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 22 Feb 2019 14:07:21 -0800 (PST) Date: Fri, 22 Feb 2019 17:07:19 -0500 From: "Michael S. Tsirkin" To: Jarkko Sakkinen Cc: Jason Gunthorpe , James Bottomley , David Tolnay , Peter Huewe , linux-integrity@vger.kernel.org, Jason Wang , virtualization@lists.linux-foundation.org, dgreid@chromium.org, apronin@chromium.org Subject: Re: [PATCH] tpm: Add driver for TPM over virtio Message-ID: <20190222170556-mutt-send-email-mst@kernel.org> References: <388c5b80-21a7-1e91-a11f-3a1c1432368b@gmail.com> <1550849416.2787.5.camel@HansenPartnership.com> <20190222160220-mutt-send-email-mst@kernel.org> <20190222213137.GZ17500@ziepe.ca> <20190222215923.GB21427@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190222215923.GB21427@linux.intel.com> Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Fri, Feb 22, 2019 at 11:59:23PM +0200, Jarkko Sakkinen wrote: > On Fri, Feb 22, 2019 at 02:31:37PM -0700, Jason Gunthorpe wrote: > > On Fri, Feb 22, 2019 at 04:16:01PM -0500, Michael S. Tsirkin wrote: > > > On Fri, Feb 22, 2019 at 07:30:16AM -0800, James Bottomley wrote: > > > > On Thu, 2019-02-21 at 18:14 -0800, David Tolnay wrote: > > > > > Add a config TCG_VIRTIO_VTPM which enables a driver providing the > > > > > guest kernel side of TPM over virtio. > > > > > > > > What's the use case for using this over the current non-virtio vTPM?. > > > > I always thought virtio was about guest to host transport efficiency, > > > > but the phsical TPM, being connected over a very slow bus, is about as > > > > inefficient as you can get in that regard, so why do we need to use > > > > virtio to drive the virtual one? > > > > > > I can't say for sure about TPM. > > > > > > But generally there are many reasons to do virtio rather than emulating > > > a hardware device. > > > > We already have a xen 'virtioish' TPM driver, so I don't think there > > is a good reason to block a virtio driver if someone cares about > > it. There are enough good reasons to prefer virtio to other options, > > IMHO. > > > > Provided it meets the general requirements for new virtio stuff you > > outlined. > > Yeah, absolutely we can consider this. > > For me it boils down to testing and documentation part. > > No plans to merge code that I'm unable to run... > > /Jarkko I do this sometimes. One can't require samples for all supported hardware. If I can check that code matches spec, I might settle for that. -- MST From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] tpm: Add driver for TPM over virtio Date: Fri, 22 Feb 2019 17:07:19 -0500 Message-ID: <20190222170556-mutt-send-email-mst@kernel.org> References: <388c5b80-21a7-1e91-a11f-3a1c1432368b@gmail.com> <1550849416.2787.5.camel@HansenPartnership.com> <20190222160220-mutt-send-email-mst@kernel.org> <20190222213137.GZ17500@ziepe.ca> <20190222215923.GB21427@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20190222215923.GB21427@linux.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jarkko Sakkinen Cc: dgreid@chromium.org, virtualization@lists.linux-foundation.org, James Bottomley , Jason Gunthorpe , linux-integrity@vger.kernel.org, Peter Huewe , apronin@chromium.org, David Tolnay List-Id: virtualization@lists.linuxfoundation.org On Fri, Feb 22, 2019 at 11:59:23PM +0200, Jarkko Sakkinen wrote: > On Fri, Feb 22, 2019 at 02:31:37PM -0700, Jason Gunthorpe wrote: > > On Fri, Feb 22, 2019 at 04:16:01PM -0500, Michael S. Tsirkin wrote: > > > On Fri, Feb 22, 2019 at 07:30:16AM -0800, James Bottomley wrote: > > > > On Thu, 2019-02-21 at 18:14 -0800, David Tolnay wrote: > > > > > Add a config TCG_VIRTIO_VTPM which enables a driver providing the > > > > > guest kernel side of TPM over virtio. > > > > > > > > What's the use case for using this over the current non-virtio vTPM?. > > > > I always thought virtio was about guest to host transport efficiency, > > > > but the phsical TPM, being connected over a very slow bus, is about as > > > > inefficient as you can get in that regard, so why do we need to use > > > > virtio to drive the virtual one? > > > > > > I can't say for sure about TPM. > > > > > > But generally there are many reasons to do virtio rather than emulating > > > a hardware device. > > > > We already have a xen 'virtioish' TPM driver, so I don't think there > > is a good reason to block a virtio driver if someone cares about > > it. There are enough good reasons to prefer virtio to other options, > > IMHO. > > > > Provided it meets the general requirements for new virtio stuff you > > outlined. > > Yeah, absolutely we can consider this. > > For me it boils down to testing and documentation part. > > No plans to merge code that I'm unable to run... > > /Jarkko I do this sometimes. One can't require samples for all supported hardware. If I can check that code matches spec, I might settle for that. -- MST