On 12/9/20 1:51 AM, Ard Biesheuvel wrote:

On Fri, 4 Dec 2020 at 22:30, Brijesh Singh [off-list ref] wrote:

quoted

The SEV FW version >= 0.23 added a new command that can be used to query
the attestation report containing the SHA-256 digest of the guest memory
encrypted through the KVM_SEV_LAUNCH_UPDATE_{DATA, VMSA} commands and
sign the report with the Platform Endorsement Key (PEK).

See the SEV FW API spec section 6.8 for more details.

Note there already exist a command (KVM_SEV_LAUNCH_MEASURE) that can be
used to get the SHA-256 digest. The main difference between the
KVM_SEV_LAUNCH_MEASURE and KVM_SEV_ATTESTATION_REPORT is that the later

latter

quoted

can be called while the guest is running and the measurement value is
signed with PEK.

Cc: James Bottomley <redacted>
Cc: Tom Lendacky <Thomas.Lendacky@amd.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: John Allen <john.allen@amd.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Brijesh Singh <redacted>
---
 .../virt/kvm/amd-memory-encryption.rst        | 21 ++++++
 arch/x86/kvm/svm/sev.c                        | 71 +++++++++++++++++++
 drivers/crypto/ccp/sev-dev.c                  |  1 +
 include/linux/psp-sev.h                       | 17 +++++
 include/uapi/linux/kvm.h                      |  8 +++
 5 files changed, 118 insertions(+)

diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index 09a8f2a34e39..4c6685d0fddd 100644
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst

@@ -263,6 +263,27 @@ Returns: 0 on success, -negative on error
                 __u32 trans_len;
         };

+10. KVM_SEV_GET_ATTESATION_REPORT

KVM_SEV_GET_ATTESTATION_REPORT

quoted

+---------------------------------
+
+The KVM_SEV_GET_ATTESATION_REPORT command can be used by the hypervisor to query the attestation

KVM_SEV_GET_ATTESTATION_REPORT

Noted, I will send v2 with these fixed.