Re: [virtio-comment] RE: [virtio-dev] Re: [virtio-comment] [PATCH] Add virtio rpmb device specification

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Aug 05, 2019 at 05:45:59AM +0000, Winkler, Tomas wrote:
> > On Sun, Aug 04, 2019 at 01:57:35PM +0000, Huang, Yang wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > > > Sent: Sunday, August 4, 2019 15:49
> > > > To: Huang, Yang <yang.huang@intel.com>
> > > > Cc: Paolo Bonzini <pbonzini@redhat.com>;
> > > > virtio-dev@lists.oasis-open.org;
> > > > virtio-comment@lists.oasis-open.org; Zhu, Bing <bing.zhu@intel.com>;
> > > > Winkler, Tomas <tomas.winkler@intel.com>
> > > > Subject: Re: [virtio-comment] RE: [virtio-dev] Re: [virtio-comment]
> > > > [PATCH] Add virtio rpmb device specification
> > > >
> > > > On Sun, Aug 04, 2019 at 02:07:49AM +0000, Huang, Yang wrote:
> > > > >
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: virtio-dev@lists.oasis-open.org
> > > > > > [mailto:virtio-dev@lists.oasis-open.org]
> > > > > > On Behalf Of Michael S. Tsirkin
> > > > > > Sent: Sunday, August 4, 2019 5:00
> > > > > > To: Huang, Yang <yang.huang@intel.com>
> > > > > > Cc: Paolo Bonzini <pbonzini@redhat.com>;
> > > > > > virtio-dev@lists.oasis-open.org;
> > > > > > virtio-comment@lists.oasis-open.org; Zhu, Bing
> > > > > > <bing.zhu@intel.com>; Winkler, Tomas <tomas.winkler@intel.com>
> > > > > > Subject: [virtio-dev] Re: [virtio-comment] [PATCH] Add virtio
> > > > > > rpmb device specification
> > > > > >
> > > > > > On Tue, Jul 30, 2019 at 12:33:17AM +0000, Huang, Yang wrote:
> > > > > > >
> > > > > > >
> > > > > > > > -----Original Message-----
> > > > > > > > From: virtio-comment@lists.oasis-open.org
> > > > > > > > [mailto:virtio-comment@lists.oasis-
> > > > > > > > open.org] On Behalf Of Paolo Bonzini
> > > > > > > > Sent: Monday, July 29, 2019 17:19
> > > > > > > > To: Huang, Yang <yang.huang@intel.com>;
> > > > > > > > virtio-dev@lists.oasis-open.org
> > > > > > > > Cc: virtio-comment@lists.oasis-open.org; mst@redhat.com;
> > > > > > > > Zhu, Bing <bing.zhu@intel.com>; Winkler, Tomas
> > > > > > > > <tomas.winkler@intel.com>
> > > > > > > > Subject: Re: [virtio-comment] [PATCH] Add virtio rpmb device
> > > > > > > > specification
> > > > > > > >
> > > > > > > > On 29/07/19 09:48, Huang Yang wrote:
> > > > > > > > >
> > > > > > > > > But virtualization software like Qemu doesn't provide
> > > > > > > > > eMMC/UFS/NVMe RPMB emulation. It blocks the OS like Trusty
> > > > > > > > > or OP-TEE running in a virtualization environment. For
> > > > > > > > > instance, Google right now uses another way to work around
> > > > > > > > > RPMB emulation issue when running Trusty in
> > > > > > > > ARM Qemu:
> > > > > > > > > https://android.googlesource.com/trusty/external/trusty/+/
> > > > > > > > > refs
> > > > > > > > > /hea
> > > > > > > > > ds/m
> > > > > > > > > aster/test-runner/
> > > > > > > > >
> > > > > > > > > Virtio RPMB standardization will definitely benefit
> > > > > > > > > OP-TEE, Google Trusty TEE, Qemu, OVMF or other modules to
> > > > > > > > > develop the RPMB based secure storage in virtualization.
> > > > > > > > >
> > > > > > > >
> > > > > > > > Is there any reason to use a new virtio-blk device, and not
> > > > > > > > add this functionality to virtio-blk?
> > > > > > > >
> > > > > > > > Paolo
> > > > > > >
> > > > > > > RPMB does not behave as a blk device. It doesn't have block device
> > APIs.
> > > > > > > Current virtio blk features or definitions in spec are mostly
> > > > > > > useless or
> > > > > > inapplicable to virtio rpmb.
> > > > > > > It performs a different behaviors from the operations on a blk device.
> > > > > > > Key, writer counter or nonce are required to read/write on it.
> > > > > > > If add it to blk device, it will not only cause to a higher
> > > > > > > complexity, but also
> > > > > > cause to two different behaviors on a same device.
> > > > > > >
> > > > > >
> > > > > >
> > > > > > Well it seems that current RPMB implementations are all tied to
> > > > > > a storage device, like MMC or NVMe. Why is that and why doesn't
> > > > > > the same
> > > > logic apply here?
> > > > > >
> > > > > > --
> > > > > > MST
> > > > > >
> > > > >
> > > > > RPMB is a mandatory hardware partition of eMMC, UFS and optional
> > > > > for
> > > > NVMe.
> > > > > It is standardized by JEDEC and NVMe.
> > > > > This partition is different from the user data partition that blk device
> > emulates.
> > > > > It provides a signed access in an authenticated and replay
> > > > > protected manner that blk device does not perform. Only RPMB key
> > > > > owner can write to it while anybody can access to a user data partition.
> > > >
> > > > Sorry if I'm being dense, so how is this different from e.g. NVMe?
> > > >
> > > > --
> > > > MST
> > >
> > > Do you refer to the difference between NVMe RPMB and eMMC RPMB?
> > > Or between NVMe RPMB partition and NVMe user data partition?
> > 
> > I refer to the fact that NVMe and eMMC are storage devices that support an
> > RPMB partition. Why is virtio blk different?
> > wouldn't it make sense for it to support an RPMB partition? 
> 
> It would make sense maybe,  though RPMB is a storage but with  ordered stream-like access, it's not a block operation, so that part cannot be used.
> RPMB has also storage  configuration operation we event haven't discussed here, that may effects the whole storage device, like marking a partition read only, 
> In that case it would make sense to attach it to block device.  On other hand I think it was  a bad decision in spec that this configuration facility was added on top of RPMB.
> 
> Thanks
> Tomas

It's more of a question of what does userspace depend on?

-- 
MST