1 files changed, 75 insertions, 0 deletions
diff --git a/pkvm/pkvm_enabler.c b/pkvm/pkvm_enabler.c
new file mode 100644
index 00000000..cb14ba6f
--- /dev/null
+++ b/pkvm/pkvm_enabler.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG     "pkvm_enabler"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <log/log.h>
+
+#define KVM_DEVICE  "/dev/kvm"
+#define MISC_WRITER "/vendor/bin/misc_writer"
+
+int main() {
+    char *newargv[] = { MISC_WRITER, "--set-enable-pkvm", NULL };
+    char *newenvp[] = { NULL };
+    pid_t pid;
+    int ret, wstatus;
+
+    /* Check whether KVM device exists. */
+    ret = access(KVM_DEVICE, F_OK);
+
+    /* If KVM device exists, return SUCCESS to continue booting. */
+    if (ret == 0) {
+        exit(EXIT_SUCCESS);
+    }
+
+    if (ret != -ENOENT) {
+        ALOGW("Unexpected error from access(): %d", ret);
+    }
+
+    /*
+     * If KVM device does not exist, run misc_writer and return FAILURE
+     * to force a reboot.
+     */
+    pid = fork();
+    if (pid == -1) {
+        ALOGE("Could not fork: %d", errno);
+        exit(EXIT_FAILURE);
+    }
+
+    if (pid == 0) {
+        execve(MISC_WRITER, newargv, newenvp);
+        ALOGE("Could not execute " MISC_WRITER ": %d", errno);
+        _exit(EXIT_FAILURE);
+    }
+
+    waitpid(pid, &wstatus, 0);
+    if (WIFEXITED(wstatus)) {
+        ret = WEXITSTATUS(wstatus);
+        if (ret) {
+            ALOGE(MISC_WRITER " exit status: %d", ret);
+        }
+    } else {
+        ALOGE(MISC_WRITER " terminated unexpectedly: %d", wstatus);
+    }
+
+    exit(EXIT_FAILURE);
+}