Re: [PATCH RFC v7 31/64] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command

[Dov Murik]

Hi Mike,

On 14/12/2022 21:40, Michael Roth wrote:
> From: Brijesh Singh <brijesh.singh@xxxxxxx>
> 
> 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@xxxxxxx>
> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
> Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
> ---
>  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
>  ============================
>