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Date:   Thu, 19 Jan 2023 09:23:26 +0200
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Subject: Re: [PATCH RFC v7 31/64] crypto: ccp: Add the
 SNP_{SET,GET}_EXT_CONFIG command
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To:     Michael Roth <michael.roth@amd.com>, kvm@vger.kernel.org
Cc:     linux-coco@lists.linux.dev, linux-mm@kvack.org,
        linux-crypto@vger.kernel.org, x86@kernel.org,
        linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com,
        jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com,
        ardb@kernel.org, pbonzini@redhat.com, seanjc@google.com,
        vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com,
        luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com,
        pgonda@google.com, peterz@infradead.org,
        srinivas.pandruvada@linux.intel.com, rientjes@google.com,
        tobin@ibm.com, bp@alien8.de, vbabka@suse.cz, kirill@shutemov.name,
        ak@linux.intel.com, tony.luck@intel.com, marcorr@google.com,
        sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com,
        dgilbert@redhat.com, jarkko@kernel.org, ashish.kalra@amd.com,
        harald@profian.com, Brijesh Singh <brijesh.singh@amd.com>,
        Dov Murik <dovmurik@linux.ibm.com>
References: <20221214194056.161492-1-michael.roth@amd.com>
 <20221214194056.161492-32-michael.roth@amd.com>
From:   Dov Murik <dovmurik@linux.ibm.com>
In-Reply-To: <20221214194056.161492-32-michael.roth@amd.com>
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Hi Mike,

On 14/12/2022 21:40, Michael Roth wrote:
> From: Brijesh Singh <brijesh.singh@amd.com>
> 
> The SEV-SNP firmware provides the SNP_CONFIG command used to set the
> system-wide configuration value for SNP guests. The information includes
> the TCB version string to be reported in guest attestation reports.
> 
> Version 2 of the GHCB specification adds an NAE (SNP extended guest
> request) that a guest can use to query the reports that include additional
> certificates.
> 
> In both cases, userspace provided additional data is included in the
> attestation reports. The userspace will use the SNP_SET_EXT_CONFIG
> command to give the certificate blob and the reported TCB version string
> at once. Note that the specification defines certificate blob with a
> specific GUID format; the userspace is responsible for building the
> proper certificate blob. The ioctl treats it an opaque blob.
> 
> While it is not defined in the spec, but let's add SNP_GET_EXT_CONFIG
> command that can be used to obtain the data programmed through the
> SNP_SET_EXT_CONFIG.
> 
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> ---
>  Documentation/virt/coco/sev-guest.rst |  27 ++++++
>  drivers/crypto/ccp/sev-dev.c          | 123 ++++++++++++++++++++++++++
>  drivers/crypto/ccp/sev-dev.h          |   4 +
>  include/uapi/linux/psp-sev.h          |  17 ++++
>  4 files changed, 171 insertions(+)
> 
> diff --git a/Documentation/virt/coco/sev-guest.rst b/Documentation/virt/coco/sev-guest.rst
> index 11ea67c944df..fad1e5639dac 100644
> --- a/Documentation/virt/coco/sev-guest.rst
> +++ b/Documentation/virt/coco/sev-guest.rst
> @@ -145,6 +145,33 @@ The SNP_PLATFORM_STATUS command is used to query the SNP platform status. The
>  status includes API major, minor version and more. See the SEV-SNP
>  specification for further details.
>  
> +2.5 SNP_SET_EXT_CONFIG
> +----------------------
> +:Technology: sev-snp
> +:Type: hypervisor ioctl cmd
> +:Parameters (in): struct sev_data_snp_ext_config
> +:Returns (out): 0 on success, -negative on error
> +
> +The SNP_SET_EXT_CONFIG is used to set the system-wide configuration such as
> +reported TCB version in the attestation report. The command is similar to
> +SNP_CONFIG command defined in the SEV-SNP spec. The main difference is the
> +command also accepts an additional certificate blob defined in the GHCB
> +specification.
> +
> +If the certs_address is zero, then the previous certificate blob will deleted.
> +For more information on the certificate blob layout, see the GHCB spec
> +(extended guest request message).
> +
> +2.6 SNP_GET_EXT_CONFIG
> +----------------------
> +:Technology: sev-snp
> +:Type: hypervisor ioctl cmd
> +:Parameters (in): struct sev_data_snp_ext_config
> +:Returns (out): 0 on success, -negative on error
> +
> +The SNP_SET_EXT_CONFIG is used to query the system-wide configuration set

       ^^^^^^^^^^^^^^^^^^

This should be SNP_GET_EXT_CONFIG.


-Dov

> +through the SNP_SET_EXT_CONFIG.
> +
>  3. SEV-SNP CPUID Enforcement
>  ============================
>