sev/i386: finalize the SEV guest launch flow

SEV launch flow requires us to issue LAUNCH_FINISH command before guest
is ready to run.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

target/i386/sev.c

@@ -578,6 +578,34 @@ static Notifier sev_machine_done_notify = {
     .notify = sev_launch_get_measure,
 };
 
+static void
+sev_launch_finish(SEVState *s)
+{
+    int ret, error;
+
+    trace_kvm_sev_launch_finish();
+    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_LAUNCH_FINISH, 0, &error);
+    if (ret) {
+        error_report("%s: LAUNCH_FINISH ret=%d fw_error=%d '%s'",
+                     __func__, ret, error, fw_error_to_str(error));
+        exit(1);
+    }
+
+    sev_set_guest_state(SEV_STATE_RUNNING);
+}
+
+static void
+sev_vm_state_change(void *opaque, int running, RunState state)
+{
+    SEVState *s = opaque;
+
+    if (running) {
+        if (!sev_check_state(SEV_STATE_RUNNING)) {
+            sev_launch_finish(s);
+        }
+    }
+}
+
 void *
 sev_guest_init(const char *id)
 {
@@ -656,6 +684,7 @@ sev_guest_init(const char *id)
 
     ram_block_notifier_add(&sev_ram_notifier);
     qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
+    qemu_add_vm_change_state_handler(sev_vm_state_change, s);
 
     return s;
 err:

target/i386/trace-events

@@ -14,3 +14,4 @@ kvm_sev_change_state(const char *old, const char *new) "%s -> %s"
 kvm_sev_launch_start(int policy, void *session, void *pdh) "policy 0x%x session %p pdh %p"
 kvm_sev_launch_update_data(void *addr, uint64_t len) "addr %p len 0x%" PRIu64
 kvm_sev_launch_measurement(const char *value) "data %s"
+kvm_sev_launch_finish(void) ""