[PATCH v2 14/22] target/arm/kvm-rme: Add Realm Personalization Value parameter

[Jean-Philippe Brucker]

The Realm Personalization Value (RPV) is provided by the user to
distinguish Realms that have the same initial measurement.

The user provides up to 64 hexadecimal bytes. They are stored into the
RPV in the same order, zero-padded on the right.

Cc: Eric Blake <eblake@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Eduardo Habkost <eduardo@habkost.net>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
v1->v2: Move parsing early, store as-is rather than reverted
---
 qapi/qom.json        |  15 +++++-
 target/arm/kvm-rme.c | 111 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 1 deletion(-)

diff --git a/qapi/qom.json b/qapi/qom.json
index 623ec8071f..91654aa267 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -931,6 +931,18 @@
   'data': { '*cpu-affinity': ['uint16'],
             '*node-affinity': ['uint16'] } }
 
+##
+# @RmeGuestProperties:
+#
+# Properties for rme-guest objects.
+#
+# @personalization-value: Realm personalization value, as a 64-byte hex string
+#     (default: 0)
+#
+# Since: FIXME
+##
+{ 'struct': 'RmeGuestProperties',
+  'data': { '*personalization-value': 'str' } }
 
 ##
 # @ObjectType:
@@ -1066,7 +1078,8 @@
       'tls-creds-x509':             'TlsCredsX509Properties',
       'tls-cipher-suites':          'TlsCredsProperties',
       'x-remote-object':            'RemoteObjectProperties',
-      'x-vfio-user-server':         'VfioUserServerProperties'
+      'x-vfio-user-server':         'VfioUserServerProperties',
+      'rme-guest':                  'RmeGuestProperties'
   } }
 
 ##
diff --git a/target/arm/kvm-rme.c b/target/arm/kvm-rme.c
index b2ad10ef6d..cb5c3f7a22 100644
--- a/target/arm/kvm-rme.c
+++ b/target/arm/kvm-rme.c
@@ -23,10 +23,13 @@ OBJECT_DECLARE_SIMPLE_TYPE(RmeGuest, RME_GUEST)
 
 #define RME_PAGE_SIZE qemu_real_host_page_size()
 
+#define RME_MAX_CFG         1
+
 struct RmeGuest {
     ConfidentialGuestSupport parent_obj;
     Notifier rom_load_notifier;
     GSList *ram_regions;
+    uint8_t *personalization_value;
 };
 
 typedef struct {
@@ -54,6 +57,48 @@ static int rme_create_rd(Error **errp)
     return ret;
 }
 
+static int rme_configure_one(RmeGuest *guest, uint32_t cfg, Error **errp)
+{
+    int ret;
+    const char *cfg_str;
+    struct kvm_cap_arm_rme_config_item args = {
+        .cfg = cfg,
+    };
+
+    switch (cfg) {
+    case KVM_CAP_ARM_RME_CFG_RPV:
+        if (!guest->personalization_value) {
+            return 0;
+        }
+        memcpy(args.rpv, guest->personalization_value, 
KVM_CAP_ARM_RME_RPV_SIZE);
+        cfg_str = "personalization value";
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    ret = kvm_vm_enable_cap(kvm_state, KVM_CAP_ARM_RME, 0,
+                            KVM_CAP_ARM_RME_CONFIG_REALM, (intptr_t)&args);
+    if (ret) {
+        error_setg_errno(errp, -ret, "RME: failed to configure %s", cfg_str);
+    }
+    return ret;
+}
+
+static int rme_configure(void)
+{
+    int ret;
+    int cfg;
+
+    for (cfg = 0; cfg < RME_MAX_CFG; cfg++) {
+        ret = rme_configure_one(rme_guest, cfg, &error_abort);
+        if (ret) {
+            return ret;
+        }
+    }
+    return 0;
+}
+
 static void rme_populate_realm(gpointer data, gpointer unused)
 {
     int ret;
@@ -98,6 +143,11 @@ static void rme_vm_state_change(void *opaque, bool running, 
RunState state)
         return;
     }
 
+    ret = rme_configure();
+    if (ret) {
+        return;
+    }
+
     ret = rme_create_rd(&error_abort);
     if (ret) {
         return;
@@ -231,8 +281,69 @@ int kvm_arm_rme_vm_type(MachineState *ms)
     return 0;
 }
 
+static char *rme_get_rpv(Object *obj, Error **errp)
+{
+    RmeGuest *guest = RME_GUEST(obj);
+    GString *s;
+    int i;
+
+    if (!guest->personalization_value) {
+        return NULL;
+    }
+
+    s = g_string_sized_new(KVM_CAP_ARM_RME_RPV_SIZE * 2 + 1);
+
+    for (i = 0; i < KVM_CAP_ARM_RME_RPV_SIZE; i++) {
+        g_string_append_printf(s, "%02x", guest->personalization_value[i]);
+    }
+
+    return g_string_free(s, /* free_segment */ false);
+}
+
+static void rme_set_rpv(Object *obj, const char *value, Error **errp)
+{
+    RmeGuest *guest = RME_GUEST(obj);
+    size_t len = strlen(value);
+    uint8_t *out;
+    int i = 1;
+    int ret;
+
+    g_free(guest->personalization_value);
+    guest->personalization_value = out = g_malloc0(KVM_CAP_ARM_RME_RPV_SIZE);
+
+    /* Two chars per byte */
+    if (len > KVM_CAP_ARM_RME_RPV_SIZE * 2) {
+        error_setg(errp, "Realm Personalization Value is too large");
+        return;
+    }
+
+    /* First byte may have a single char */
+    if (len % 2) {
+        ret = sscanf(value, "%1hhx", out++);
+    } else {
+        ret = sscanf(value, "%2hhx", out++);
+        i++;
+    }
+    if (ret != 1) {
+        error_setg(errp, "Invalid Realm Personalization Value");
+        return;
+    }
+
+    for (; i < len; i += 2) {
+        ret = sscanf(value + i, "%2hhx", out++);
+        if (ret != 1) {
+            error_setg(errp, "Invalid Realm Personalization Value");
+            return;
+        }
+    }
+}
+
 static void rme_guest_class_init(ObjectClass *oc, void *data)
 {
+    object_class_property_add_str(oc, "personalization-value", rme_get_rpv,
+                                  rme_set_rpv);
+    object_class_property_set_description(oc, "personalization-value",
+            "Realm personalization value (512-bit hexadecimal number)");
 }
 
 static void rme_guest_instance_init(Object *obj)
-- 
2.44.0