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

["Huang, Yang" <yang.huang@intel.com>]

> -----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/heads/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.