docs: add firmware feature flags

Add new firmware feature flags for the recently added confidential
computing operating modes by amd and intel.

While being at it also fix the path to the amd sev documentation.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com>
Message-Id: <20220930133220.1771336-1-kraxel@redhat.com>

docs/interop/firmware.json

@@ -113,13 +113,22 @@
 #           Virtualization, as specified in the AMD64 Architecture
 #           Programmer's Manual. QEMU command line options related to
 #           this feature are documented in
-#           "docs/amd-memory-encryption.txt".
+#           "docs/system/i386/amd-memory-encryption.rst".
 #
 # @amd-sev-es: The firmware supports running under AMD Secure Encrypted
 #              Virtualization - Encrypted State, as specified in the AMD64
 #              Architecture Programmer's Manual. QEMU command line options
 #              related to this feature are documented in
-#              "docs/amd-memory-encryption.txt".
+#              "docs/system/i386/amd-memory-encryption.rst".
+#
+# @amd-sev-snp: The firmware supports running under AMD Secure Encrypted
+#               Virtualization - Secure Nested Paging, as specified in the
+#               AMD64 Architecture Programmer's Manual. QEMU command line
+#               options related to this feature are documented in
+#               "docs/system/i386/amd-memory-encryption.rst".
+#
+# @intel-tdx: The firmware supports running under Intel Trust Domain
+#             Extensions (TDX).
 #
 # @enrolled-keys: The variable store (NVRAM) template associated with
 #                 the firmware binary has the UEFI Secure Boot
@@ -185,9 +194,11 @@
 # Since: 3.0
 ##
 { 'enum' : 'FirmwareFeature',
-  'data' : [ 'acpi-s3', 'acpi-s4', 'amd-sev', 'amd-sev-es', 'enrolled-keys',
-             'requires-smm', 'secure-boot', 'verbose-dynamic',
-             'verbose-static' ] }
+  'data' : [ 'acpi-s3', 'acpi-s4',
+             'amd-sev', 'amd-sev-es', 'amd-sev-snp',
+             'intel-tdx',
+             'enrolled-keys', 'requires-smm', 'secure-boot',
+             'verbose-dynamic', 'verbose-static' ] }
 
 ##
 # @FirmwareFlashFile: