From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Matthew Garrett <mjg59@google.com>
Cc: David Tolnay <dtolnay@gmail.com>, Peter Huewe <peterhuewe@gmx.de>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
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 14:51:46 -0800 [thread overview]
Message-ID: <1551135106.3226.91.camel@HansenPartnership.com> (raw)
In-Reply-To: <CACdnJuvhqHCuA7x2oyAaHB1zWnQ5T_4vTSc=FT3h85+sMSmwfg@mail.gmail.com>
On Mon, 2019-02-25 at 14:43 -0800, Matthew Garrett wrote:
> On Mon, Feb 25, 2019 at 2:32 PM James Bottomley
> <James.Bottomley@hansenpartnership.com> wrote:
> > On Mon, 2019-02-25 at 14:24 -0800, Matthew Garrett wrote:
> > > My understanding is that the crosvm USB code is intended to allow
> > > arbitrary USB hardware to be passed through to the guest - doing
> > > this
> > > via virtio sounds complicated (you'd need a virtio driver that
> > > covered every USB class, and how would you manage that for
> > > devices
> > > that are handled in userland at the moment),
> >
> > I think you'd need a virtio equivalent of the host driver, say
> > xhci_virtio ... you could still use the in-kernel USB class drivers
>
> Mm. I honestly don't know enough about the desired use case for USB
> to be able to provide meaningful input here.
>
> > > > Effectively it bypasses the hypervisor altogether and simply
> > > > makes a direct connection to the host devices. The TPM could
> > > > actually work in exactly the same way, except you'd have to use
> > > > the socsim IP connection (which all TSSs support) rather than a
> > > > file descriptor.
> > >
> > > I don't really follow - how would in-kernel TPM features work
> > > then?
> >
> > If you do it at the TSS layer, then, of course, the kernel wouldn't
> > participate. If you used the proposed in-kernel socsim driver, I
> > suppose it could ... not that I'm advocating this, I'm saying if
> > you want to minimise hypervisor code for attack surface reduction,
> > this would be the way to do it because this solution requires no
> > in-hypervisor code at all.
>
> You still need a transport mechanism through the hypervisor to
> communicate with the host - what would you be using in that case
> instead of virtio?
Socsim is net transported; it's sort of the TPM equivalent of NFS or
iSCSI storage for guests.
James
next prev parent reply other threads:[~2019-02-25 22:51 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 [this message]
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
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