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Date:   Fri, 28 Jul 2023 19:34:52 +0000
Message-Id: <CUE22P5RYPH3.1K05T2OCK1CN1@seitikki>
Cc:     "Brijesh Singh" <brijesh.singh@amd.com>,
        "Kuppuswamy Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        "Peter Zijlstra" <peterz@infradead.org>,
        "Tom Lendacky" <thomas.lendacky@amd.com>,
        "Dionna Amalie Glaze" <dionnaglaze@google.com>,
        "Borislav Petkov" <bp@alien8.de>,
        "Samuel Ortiz" <sameo@rivosinc.com>,
        "Dionna Glaze" <dionnaglaze@google.com>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Andrew Morton" <akpm@linux-foundation.org>,
        <linux-coco@lists.linux.dev>, <keyrings@vger.kernel.org>,
        <x86@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] keys: Introduce a keys frontend for attestation
 reports
From:   "Jarkko Sakkinen" <jarkko@kernel.org>
To:     "Dan Williams" <dan.j.williams@intel.com>, <dhowells@redhat.com>
References: <169057265210.180586.7950140104251236598.stgit@dwillia2-xfh.jf.intel.com>
In-Reply-To: <169057265210.180586.7950140104251236598.stgit@dwillia2-xfh.jf.intel.com>
Precedence: bulk

On Fri Jul 28, 2023 at 7:30 PM UTC, Dan Williams wrote:
> The bulk of the justification for this patch kit is in "[PATCH 1/4]

/patch kit/patch set/

> keys: Introduce tsm keys". The short summary is that the current
> approach of adding new char devs and new ioctls, for what amounts to the
> same functionality with minor formatting differences across vendors, is
> untenable. Common concepts and the community benefit from common
> infrastructure.
>
> Use Keys to build common infrastructure for confidential computing

/Keys/Linux keyring/

> attestation report blobs, convert sevguest to use it (leaving the
> deprecation question alone for now), and pave the way for tdx-guest and
> the eventual risc-v equivalent to use it in lieu of new ioctls.
>
> The sevguest conversion is only compile-tested.
>
> This submission is To:David since he needs to sign-off on the idea of a
> new Keys type, the rest is up to the confidential-computing driver
> maintainers to adopt.
>
> Changes from / credit for internal review:
> - highlight copy_{to,from}_sockptr() as a common way to mix
>   copy_user() and memcpy() paths (Andy)
> - add MODULE_DESCRIPTION() (Andy)
> - clarify how the user-defined portion blob might be used (Elena)
> - clarify the key instantiation options (Sathya)
> - drop usage of a list for registering providers (Sathya)
> - drop list.h include from tsm.h (Andy)
> - add a comment for how TSM_DATA_MAX was derived (Andy)
> - stop open coding kmemdup_nul() (Andy)
> - add types.h to tsm.h (Andy)
> - fix punctuation in comment (Andy)
> - reorder security/keys/Makefile (Andy)
> - add some missing includes to tsm.c (Andy)
> - undo an 81 column clang-format line break (Andy)
> - manually reflow tsm_token indentation (Andy)
> - move allocations after input validation in tsm_instantiate() (Andy)
> - switch to bin2hex() in tsm_read() (Andy)
> - move init/exit declarations next to their functions (Andy)
>
>
> ---
>
> Dan Williams (4):
>       keys: Introduce tsm keys
>       virt: sevguest: Prep for kernel internal {get,get_ext}_report()
>       mm/slab: Add __free() support for kvfree
>       virt: sevguest: Add TSM key support for SNP_{GET,GET_EXT}_REPORT
>
>
>  drivers/virt/coco/sev-guest/Kconfig     |    2=20
>  drivers/virt/coco/sev-guest/sev-guest.c |  135 ++++++++++++++-
>  include/keys/tsm.h                      |   71 ++++++++
>  include/linux/slab.h                    |    2=20
>  security/keys/Kconfig                   |   12 +
>  security/keys/Makefile                  |    1=20
>  security/keys/tsm.c                     |  282 +++++++++++++++++++++++++=
++++++
>  7 files changed, 494 insertions(+), 11 deletions(-)
>  create mode 100644 include/keys/tsm.h
>  create mode 100644 security/keys/tsm.c
>
> base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5

So how does this scale? Does it scale to TDX, SGX, TPM's or even TEE's
(ARM SM, RISC-V Keystone etc.). I'm not sure about the scope but we want
of course something that adapts to multiple use cases, right?

BR, Jarkko