Re: [PATCH v5 12/13] x86/sev: Extend the config-fs attestation support for an SVSM

[Tom Lendacky]

On 6/5/24 10:18, Tom Lendacky wrote:
> When an SVSM is present, the guest can also request attestation reports
> from the SVSM. These SVSM attestation reports can be used to attest the
> SVSM and any services running within the SVSM.
>
> Extend the config-fs attestation support to allow for an SVSM attestation
> report. This involves creating four (4) new config-fs attributes:
>
>    - 'service-provider' (input)
>      This attribute is used to determine whether the attestation request
>      should be sent to the specified service provider or to the SEV
>      firmware. The SVSM service provider is represented by the value
>      'svsm'.
>
>    - 'service_guid' (input)
>      Used for requesting the attestation of a single service within the
>      service provider. A null GUID implies that the SVSM_ATTEST_SERVICES
>      call should be used to request the attestation report. A non-null
>      GUID implies that the SVSM_ATTEST_SINGLE_SERVICE call should be used.
>
>    - 'service_manifest_version' (input)
>      Used with the SVSM_ATTEST_SINGLE_SERVICE call, the service version
>      represents a specific service manifest version be used for the
>      attestation report.
>
>    - 'manifestblob' (output)
>      Used to return the service manifest associated with the attestation
>      report.
>
> Only display these new attributes when running under an SVSM.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
>   Documentation/ABI/testing/configfs-tsm  |  63 +++++++++
>   arch/x86/include/asm/sev.h              |  31 ++++-
>   arch/x86/kernel/sev.c                   |  50 +++++++
>   drivers/virt/coco/sev-guest/sev-guest.c | 178 ++++++++++++++++++++++++
>   drivers/virt/coco/tsm.c                 |  93 ++++++++++++-
>   include/linux/tsm.h                     |  19 +++
>   6 files changed, 431 insertions(+), 3 deletions(-)

Here's a small change to provide better error detail that you can squash
into this patch if that's ok.

Thanks,
Tom

diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 655865164705..e32ac31e0630 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -886,7 +886,8 @@ static int sev_svsm_report_new(struct tsm_report *report, void *data)
 
 			return -EINVAL;
 		default:
-			pr_err_ratelimited("SVSM attestation request failed (%#x)\n", ret);
+			pr_err_ratelimited("SVSM attestation request failed (%d / 0x%llx)\n",
+					   ret, call.rax_out);
 			return -EINVAL;
 		}
 	}