device/virtio-nsm: Support for Nitro Secure Module device

Nitro Secure Module (NSM)[1] device is used in AWS Nitro Enclaves[2]
for stripped down TPM functionality like cryptographic attestation.
The requests to and responses from NSM device are CBOR[3] encoded.

This commit adds support for NSM device in QEMU. Although related to
AWS Nitro Enclaves, the virito-nsm device is independent and can be
used in other machine types as well. The libcbor[4] library has been
used for the CBOR encoding and decoding functionalities.

[1] https://lists.oasis-open.org/archives/virtio-comment/202310/msg00387.html
[2] https://docs.aws.amazon.com/enclaves/latest/user/nitro-enclave.html
[3] http://cbor.io/
[4] https://libcbor.readthedocs.io/en/latest/

Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Link: https://lore.kernel.org/r/20241008211727.49088-3-dorjoychy111@gmail.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 94 insertions, 0 deletions

diff --git a/include/hw/virtio/cbor-helpers.h b/include/hw/virtio/cbor-helpers.h
new file mode 100644
index 0000000..f25fd48
--- /dev/null
+++ b/include/hw/virtio/cbor-helpers.h
@@ -0,0 +1,45 @@
+/*
+ * QEMU CBOR helpers
+ *
+ * Copyright (c) 2024 Dorjoy Chowdhury <dorjoychy111@gmail.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#ifndef QEMU_VIRTIO_CBOR_HELPERS_H
+#define QEMU_VIRTIO_CBOR_HELPERS_H
+
+#include <cbor.h>
+
+bool qemu_cbor_map_add(cbor_item_t *map, cbor_item_t *key, cbor_item_t *value);
+
+bool qemu_cbor_array_push(cbor_item_t *array, cbor_item_t *value);
+
+bool qemu_cbor_add_bool_to_map(cbor_item_t *map, const char *key, bool value);
+
+bool qemu_cbor_add_uint8_to_map(cbor_item_t *map, const char *key,
+                                uint8_t value);
+
+bool qemu_cbor_add_map_to_map(cbor_item_t *map, const char *key,
+                              size_t nested_map_size,
+                              cbor_item_t **nested_map);
+
+bool qemu_cbor_add_bytestring_to_map(cbor_item_t *map, const char *key,
+                                     uint8_t *arr, size_t len);
+
+bool qemu_cbor_add_null_to_map(cbor_item_t *map, const char *key);
+
+bool qemu_cbor_add_string_to_map(cbor_item_t *map, const char *key,
+                                 const char *value);
+
+bool qemu_cbor_add_uint8_array_to_map(cbor_item_t *map, const char *key,
+                                      uint8_t *arr, size_t len);
+
+bool qemu_cbor_add_uint8_key_bytestring_to_map(cbor_item_t *map, uint8_t key,
+                                               uint8_t *buf, size_t len);
+
+bool qemu_cbor_add_uint64_to_map(cbor_item_t *map, const char *key,
+                                 uint64_t value);
+#endif
diff --git a/include/hw/virtio/virtio-nsm.h b/include/hw/virtio/virtio-nsm.h
new file mode 100644
index 0000000..57ddbbb
--- /dev/null
+++ b/include/hw/virtio/virtio-nsm.h
@@ -0,0 +1,49 @@
+/*
+ * AWS Nitro Secure Module (NSM) device
+ *
+ * Copyright (c) 2024 Dorjoy Chowdhury <dorjoychy111@gmail.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#ifndef QEMU_VIRTIO_NSM_H
+#define QEMU_VIRTIO_NSM_H
+
+#include "crypto/hash.h"
+#include "hw/virtio/virtio.h"
+#include "qom/object.h"
+
+#define NSM_MAX_PCRS 32
+
+#define TYPE_VIRTIO_NSM "virtio-nsm-device"
+OBJECT_DECLARE_SIMPLE_TYPE(VirtIONSM, VIRTIO_NSM)
+#define VIRTIO_NSM_GET_PARENT_CLASS(obj) \
+    OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_NSM)
+
+struct PCRInfo {
+    bool locked;
+    uint8_t data[QCRYPTO_HASH_DIGEST_LEN_SHA384];
+};
+
+struct VirtIONSM {
+    VirtIODevice parent_obj;
+
+    /* Only one vq - guest puts request and response buffers on it */
+    VirtQueue *vq;
+
+    /* NSM State */
+    uint16_t max_pcrs;
+    struct PCRInfo pcrs[NSM_MAX_PCRS];
+    char *digest;
+    char *module_id;
+    uint8_t version_major;
+    uint8_t version_minor;
+    uint8_t version_patch;
+
+    bool (*extend_pcr)(VirtIONSM *vnsm, int ind, uint8_t *data, uint16_t len);
+    void (*lock_pcr)(VirtIONSM *vnsm, int ind);
+};
+
+#endif