From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Stefan Berger" Subject: Re: [PATCH v5 4/5] Initialize TPM and get durations and timeouts Date: Tue, 9 Feb 2016 11:19:15 -0500 Message-ID: <201602091626.u19GQrRs003549@d03av03.boulder.ibm.com> References: <1454959628-30582-1-git-send-email-stefanb@linux.vnet.ibm.com><1454959628-30582-5-git-send-email-stefanb@linux.vnet.ibm.com> <20160209053323.GD12657@obsidianresearch.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2097807649996835747==" Return-path: In-Reply-To: <20160209053323.GD12657-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jason Gunthorpe Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net --===============2097807649996835747== Content-Type: multipart/alternative; boundary="=_alternative 0059AE4A85257F54_=" --=_alternative 0059AE4A85257F54_= Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="US-ASCII" Jason Gunthorpe wrote on 02/09/2016=20 12:33:23 AM: >=20 > On Mon, Feb 08, 2016 at 02:27:07PM -0500, Stefan Berger wrote: > > Add the retrieval of TPM 1.2 durations and timeouts. Since this=20 requires > > the startup of the TPM, do this for TPM 1.2 and TPM 2. > >=20 > > To not allow to interleave with commands from user space, so send the > > TPM=5FStartup as the first command. The timeouts can then be gotten at = any > > later time, even interleaved with commands from user space. >=20 > Do not call tpm=5Fregister until get=5Ftimeouts has completed and this > will naturally be avoided the same way every other TPM driver does. Getting the timeouts cannot complete before the TPM emulator has started,=20 which in turn cannot start before the ioctl returns. We don't know whether = user space starts a client first on /dev/tpm1 or the TPM emulator starts=20 first on the file descriptor. We can control which command gets *queued*=20 for the TPM emulator and that's what I am doing by having the kernel queue = the startup command first. I moved the start of the work call before the tpm=5Fchip=5Fregister, so tha= t=20 we *queue* the TPM=5FStartup before user space can send its first command. >=20 > The long term goal is to move the get=5Ftimeouts call into tpm=5Fregister. That may become a problem then. Stefan >=20 > Jason >=20 >=20 ---------------------------------------------------------------------------= --- > Site24x7 APM Insight: Get Deep Visibility into Application Performance > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month > Monitor end-to-end web transactions and take corrective actions now > Troubleshoot faster and improve end-user experience. Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=3D272487151&iu=3D/4140 > =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F > tpmdd-devel mailing list > tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > https://lists.sourceforge.net/lists/listinfo/tpmdd-devel >=20 --=_alternative 0059AE4A85257F54_= Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="US-ASCII" Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> wrote on 02/09/2016 12:33:23 AM:


= >
> On Mon, Feb 08, 2016 at 02:27:07PM -0500, Stefan Berger wrote= :
> > Add the retrieval of TPM 1.2 durations and timeouts. Since t= his requires
> > the startup of the TPM, do this for TPM 1.2 and TPM 2= .
> >
> > To not allow to interleave with commands from = user space, so send the
> > TPM=5FStartup as the first command. The timeouts can = then be gotten at any
> > later time, even interleaved with commands from user sp= ace.
>
> Do not call tpm=5Fregister until get=5Ftimeouts has c= ompleted and this
> will naturally be avoided the same way every othe= r TPM driver does.

Getting the timeou= ts cannot complete before the TPM emulator has started, which in turn cannot start before the ioctl returns. We don't know whether user space starts a client first on /dev/tpm1 or the TPM emulator starts first on the file descriptor. We can control which command gets *queued* for the TPM emulator and that's what I am doing by having the kernel queue the startup command first.

<= font size=3D2>I moved the start of the work call before the tpm=5Fchip=5Fre= gister, so that we *queue* the TPM=5FStartup before user space can send its first command.

>
> The long term = goal is to move the get=5Ftimeouts call into tpm=5Fregister.
That may become a problem then.

=    Stefan
>
> Jason
>
> ------------------------------------= ------------------------------------------
> Site24x7 APM Insight: Ge= t Deep Visibility into Application Performance
> APM + Mobile APM + R= UM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end we= b transactions and take corrective actions now
> Troubleshoot faster = and improve end-user experience. Signup Now!
> = http://pubads.g.doubleclick.net/gampad/clk?id=3D27248715= 1&iu=3D/4140
> =5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F
> tpmdd-devel mai= ling list
> tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> https://lists.sourceforge.net/lists/listinfo/tpmdd-devel
>

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