1 files changed, 187 insertions, 0 deletions
diff --git a/hw/nvme/nguid.c b/hw/nvme/nguid.c
new file mode 100644
index 0000000000..829832bd9f
--- /dev/null
+++ b/hw/nvme/nguid.c
@@ -0,0 +1,187 @@
+/*
+ *  QEMU NVMe NGUID functions
+ *
+ * Copyright 2024 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/visitor.h"
+#include "qemu/ctype.h"
+#include "nvme.h"
+
+#define NGUID_SEPARATOR '-'
+
+#define NGUID_VALUE_AUTO "auto"
+
+#define NGUID_FMT              \
+    "%02hhx%02hhx%02hhx%02hhx" \
+    "%02hhx%02hhx%02hhx%02hhx" \
+    "%02hhx%02hhx%02hhx%02hhx" \
+    "%02hhx%02hhx%02hhx%02hhx"
+
+#define NGUID_STR_LEN (2 * NGUID_LEN + 1)
+
+bool nvme_nguid_is_null(const NvmeNGUID *nguid)
+{
+    static NvmeNGUID null_nguid;
+    return memcmp(nguid, &null_nguid, sizeof(NvmeNGUID)) == 0;
+}
+
+static void nvme_nguid_generate(NvmeNGUID *out)
+{
+    int i;
+    uint32_t x;
+
+    QEMU_BUILD_BUG_ON((NGUID_LEN % sizeof(x)) != 0);
+
+    for (i = 0; i < NGUID_LEN; i += sizeof(x)) {
+        x = g_random_int();
+        memcpy(&out->data[i], &x, sizeof(x));
+    }
+}
+
+/*
+ * The Linux Kernel typically prints the NGUID of an NVMe namespace using the
+ * same format as the UUID. For instance:
+ *
+ * $ cat /sys/class/block/nvme0n1/nguid
+ * e9accd3b-8390-4e13-167c-f0593437f57d
+ *
+ * When there is no UUID but there is NGUID the Kernel will print the NGUID as
+ * wwid and it won't use the UUID format:
+ *
+ * $ cat /sys/class/block/nvme0n1/wwid
+ * eui.e9accd3b83904e13167cf0593437f57d
+ *
+ * The NGUID has different fields compared to the UUID, so the grouping used in
+ * the UUID format has no relation with the 3 fields of the NGUID.
+ *
+ * This implementation won't expect a strict format as the UUID one and instead
+ * it will admit any string of hexadecimal digits. Byte groups could be created
+ * using the '-' separator. The number of bytes needs to be exactly 16 and the
+ * separator '-' has to be exactly in a byte boundary. The following are
+ * examples of accepted formats for the NGUID string:
+ *
+ * nguid="e9accd3b-8390-4e13-167c-f0593437f57d"
+ * nguid="e9accd3b83904e13167cf0593437f57d"
+ * nguid="FEDCBA9876543210-ABCDEF-0123456789"
+ */
+static bool nvme_nguid_is_valid(const char *str)
+{
+    int i;
+    int digit_count = 0;
+
+    for (i = 0; i < strlen(str); i++) {
+        const char c = str[i];
+        if (qemu_isxdigit(c)) {
+            digit_count++;
+            continue;
+        }
+        if (c == NGUID_SEPARATOR) {
+            /*
+             * We need to make sure the separator is in a byte boundary, the
+             * string does not start with the separator and they are not back to
+             * back "--".
+             */
+            if ((i > 0) && (str[i - 1] != NGUID_SEPARATOR) &&
+                (digit_count % 2) == 0) {
+                continue;
+            }
+        }
+        return false;
+    }
+    /*
+     * The string should have the correct byte length and not finish with the
+     * separator
+     */
+    return (digit_count == (2 * NGUID_LEN)) && (str[i - 1] != NGUID_SEPARATOR);
+}
+
+static int nvme_nguid_parse(const char *str, NvmeNGUID *nguid)
+{
+    uint8_t *id = &nguid->data[0];
+    int ret = 0;
+    int i;
+    const char *ptr = str;
+
+    if (!nvme_nguid_is_valid(str)) {
+        return -1;
+    }
+
+    for (i = 0; i < NGUID_LEN; i++) {
+        ret = sscanf(ptr, "%02hhx", &id[i]);
+        if (ret != 1) {
+            return -1;
+        }
+        ptr += 2;
+        if (*ptr == NGUID_SEPARATOR) {
+            ptr++;
+        }
+    }
+
+    return 0;
+}
+
+/*
+ * When converted back to string this implementation will use a raw hex number
+ * with no separators, for instance:
+ *
+ * "e9accd3b83904e13167cf0593437f57d"
+ */
+static void nvme_nguid_stringify(const NvmeNGUID *nguid, char *out)
+{
+    const uint8_t *id = &nguid->data[0];
+    snprintf(out, NGUID_STR_LEN, NGUID_FMT,
+             id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7],
+             id[8], id[9], id[10], id[11], id[12], id[13], id[14], id[15]);
+}
+
+static void get_nguid(Object *obj, Visitor *v, const char *name, void *opaque,
+                      Error **errp)
+{
+    Property *prop = opaque;
+    NvmeNGUID *nguid = object_field_prop_ptr(obj, prop);
+    char buffer[NGUID_STR_LEN];
+    char *p = buffer;
+
+    nvme_nguid_stringify(nguid, buffer);
+
+    visit_type_str(v, name, &p, errp);
+}
+
+static void set_nguid(Object *obj, Visitor *v, const char *name, void *opaque,
+                      Error **errp)
+{
+    Property *prop = opaque;
+    NvmeNGUID *nguid = object_field_prop_ptr(obj, prop);
+    char *str;
+
+    if (!visit_type_str(v, name, &str, errp)) {
+        return;
+    }
+
+    if (!strcmp(str, NGUID_VALUE_AUTO)) {
+        nvme_nguid_generate(nguid);
+    } else if (nvme_nguid_parse(str, nguid) < 0) {
+        error_set_from_qdev_prop_error(errp, EINVAL, obj, name, str);
+    }
+    g_free(str);
+}
+
+const PropertyInfo qdev_prop_nguid = {
+    .name  = "str",
+    .description =
+        "NGUID or \"" NGUID_VALUE_AUTO "\" for random value",
+    .get   = get_nguid,
+    .set   = set_nguid,
+};