From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Matthew Garrett <mjg59@google.com>,
David Tolnay <dtolnay@gmail.com>, Peter Huewe <peterhuewe@gmx.de>,
Jason Gunthorpe <jgg@ziepe.ca>,
linux-integrity <linux-integrity@vger.kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
virtualization@lists.linux-foundation.org, dgreid@chromium.org,
apronin@chromium.org
Subject: Re: [PATCH] tpm: Add driver for TPM over virtio
Date: Mon, 25 Feb 2019 14:24:51 -0800 [thread overview]
Message-ID: <1551133491.3226.75.camel@HansenPartnership.com> (raw)
In-Reply-To: <20190225210511.GA8727@linux.intel.com>
On Mon, 2019-02-25 at 23:05 +0200, Jarkko Sakkinen wrote:
> On Mon, Feb 25, 2019 at 12:20:43PM -0800, James Bottomley wrote:
> > On Mon, 2019-02-25 at 11:17 -0800, Matthew Garrett wrote:
> > > On Mon, Feb 25, 2019 at 7:36 AM James Bottomley
> > > <James.Bottomley@hansenpartnership.com> wrote:
> > > > > The virtio driver performs discovery via virtio, which crosvm
> > > > > implements already for all of its supported devices. This
> > > > > substantially reduces the amount of TPM-specific code
> > > > > compared to your suggestions, and lowers the barrier to entry
> > > > > for implementing TPM support in other hypervisors which I
> > > > > hope we agree is beneficial.
> > > >
> > > > Well, that's somewhat misleading: The reason we already have
> > > > two hypervisor specific drivers already is because every
> > > > hypervisor has a different virtual discovery mechanism. You
> > > > didn't find the other two hypervisor drivers remotely useful,
> > > > so why would another hypervisor find yours useful?
> > >
> > >
> > > The existing hypervisor drivers expose hypervisor-specific
> > > details. This proposed driver provides an abstract interface that
> > > is usable by other hypervisors. It allows building a VM that
> > > exposes TPM functionality without requiring additional hardware
> > > emulation, reducing the hypervisor attack surface.
> >
> > Well, that depends whether you think a virtio bus is an abstract
> > concept or a hypervisor specific detail. There are currently four
> > major hypervisors: xen, kvm, hyper-v and ESX. Of those, only one
> > implements virtio: kvm. I agree virtio is a standard and certainly
> > a slew of minor hypervisors implement it because they need paravirt
> > support on Linux so they piggyback off kvm, but I don't see any of
> > the other major hypervisors jumping on the bandwagon.
> >
> > I certainly agree our lives would be easier if all the major
> > hypervisor vendors would just agree a single paravirt driver
> > standard.
>
> I think that a Windows hypervisor (Hyper-V) and a closed hypervisor
> (VMWare) are out of context for this discussion.
But why? We already have both in various Linux subsystems; for
instance SCSI has storvsc (hyper-v paravirt storage driver) and
vmw_pvscsi (VMWare paravirt storage dirver). The only real requirement
is a willingness to open source the driver and publish the
communication spec. If another paravirt TPM driver is a good idea, why
wouldn't we allow these guys to play in our sandpit too (under the
right open source conditions, of course)?
James
prev parent reply other threads:[~2019-02-25 22:24 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-22 2:14 [PATCH] tpm: Add driver for TPM over virtio David Tolnay
2019-02-22 5:51 ` Michael S. Tsirkin
2019-02-22 21:40 ` David Tolnay
2019-02-22 22:24 ` Michael S. Tsirkin
2019-02-23 1:23 ` David Tolnay
2019-02-25 9:58 ` Jarkko Sakkinen
2019-02-22 10:26 ` Jarkko Sakkinen
2019-02-22 15:23 ` Michael S. Tsirkin
2019-02-22 19:31 ` Jarkko Sakkinen
2019-02-22 19:33 ` Jarkko Sakkinen
2019-02-22 21:25 ` Michael S. Tsirkin
2019-02-22 21:50 ` Jarkko Sakkinen
2019-02-22 22:24 ` David Tolnay
2019-02-22 22:36 ` Jarkko Sakkinen
2019-02-22 23:05 ` Michael S. Tsirkin
2019-02-24 9:33 ` Jarkko Sakkinen
2019-02-22 20:55 ` Michael S. Tsirkin
2019-02-22 21:30 ` Jarkko Sakkinen
2019-02-22 10:30 ` Jarkko Sakkinen
2019-02-22 15:30 ` James Bottomley
2019-02-22 21:16 ` Michael S. Tsirkin
2019-02-22 21:31 ` Jason Gunthorpe
2019-02-22 21:59 ` Jarkko Sakkinen
2019-02-22 22:07 ` Michael S. Tsirkin
2019-02-22 22:14 ` Jarkko Sakkinen
2019-02-22 22:00 ` David Tolnay
2019-02-22 22:18 ` James Bottomley
2019-02-23 0:45 ` David Tolnay
2019-02-23 1:34 ` James Bottomley
2019-02-23 2:41 ` David Tolnay
2019-02-24 16:30 ` James Bottomley
2019-02-24 17:51 ` Jarkko Sakkinen
2019-02-24 22:12 ` David Tolnay
2019-02-25 9:55 ` Jarkko Sakkinen
2019-02-25 15:36 ` James Bottomley
2019-02-25 19:17 ` Matthew Garrett
2019-02-25 19:54 ` Jarkko Sakkinen
2019-02-25 20:20 ` James Bottomley
2019-02-25 21:00 ` Matthew Garrett
2019-02-25 21:02 ` Matthew Garrett
2019-02-25 22:14 ` James Bottomley
2019-02-25 22:24 ` Matthew Garrett
2019-02-25 22:32 ` James Bottomley
2019-02-25 22:43 ` Matthew Garrett
2019-02-25 22:51 ` James Bottomley
2019-02-25 23:02 ` Matthew Garrett
2019-02-25 23:09 ` James Bottomley
2019-02-25 21:05 ` Jarkko Sakkinen
2019-02-25 22:24 ` James Bottomley [this message]
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