Re: [PATCH v7] misc: Add Nitro Secure Module driver

[Michael S. Tsirkin]

On Mon, Dec 25, 2023 at 05:07:29PM +0100, Alexander Graf wrote:
> Hey Michael,
> 
> On 25.12.23 15:06, Michael S. Tsirkin wrote:
> > On Wed, Oct 11, 2023 at 09:35:22PM +0000, Alexander Graf wrote:
> > > When running Linux inside a Nitro Enclave, the hypervisor provides a
> > > special virtio device called "Nitro Security Module" (NSM). This device
> > > has 3 main functions:
> > > 
> > >    1) Provide attestation reports
> > >    2) Modify PCR state
> > >    3) Provide entropy
> > > 
> > > This patch adds a driver for NSM that exposes a /dev/nsm device node which
> > > user space can issue an ioctl on this device with raw NSM CBOR formatted
> > > commands to request attestation documents, influence PCR states, read
> > > entropy and enumerate status of the device. In addition, the driver
> > > implements a hwrng backend.
> > > 
> > > Originally-by: Petre Eftime <petre.eftime@xxxxxxxxx>
> > > Signed-off-by: Alexander Graf <graf@xxxxxxxxxx>
> > Alex are you going to publish the spec patch for this device?  Important
> > so we don't need to guess at behaviour when e.g.  making changes to
> > virtio APIs.  Also, which tree do you want this to go through?
> 
> 
> The spec patch including ping mail are sitting on the virtio-comments
> mailing list since October. I haven't seen any reply unfortunately :(
> 
> https://lore.kernel.org/virtio-comment/20231025235345.17788-1-graf@xxxxxxxxxx/
> 
> Happy to read feedback if you have any :).

Oh I forgot.
Now that I've read the driver, I actually have some :)
I think there's an assumption that there's a request buffer
and response buffer queued by the driver, and that
the device always first consumes the request buffer
followed by consuming the response buffer.
If that is right then driver is ok but spec needs
clarification, will note on virtio-comment.


> This patch here is already applied in Greg's misc tree which I'm happy to
> have it trickle to Linus through.
> 
> 
> Alex
> 
> 
> 
> 
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