[Qemu-devel] [PATCH v5 09/12] s390-ccw: print zipl boot menu

["Collin L. Walling" <walling@linux.vnet.ibm.com>]

When the boot menu options are present and the guest's
disk has been configured by the zipl tool, then the user
will be presented with an interactive boot menu with
labeled entries. An example of what the menu might look
like:

zIPL v1.37.1-build-20170714 interactive boot menu.

  0. default (linux-4.13.0)

  1. linux-4.13.0
  2. performance
  3. kvm

Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 pc-bios/s390-ccw/menu.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/pc-bios/s390-ccw/menu.c b/pc-bios/s390-ccw/menu.c
index 4ba2684..e9e283f 100644
--- a/pc-bios/s390-ccw/menu.c
+++ b/pc-bios/s390-ccw/menu.c
@@ -10,13 +10,60 @@
  */
 
 #include "menu.h"
+#include "s390-ccw.h"
 
 static uint8_t flags;
 static uint64_t timeout;
 
+/* Offsets from zipl fields to zipl banner start */
+#define ZIPL_TIMEOUT_OFFSET 138
+#define ZIPL_FLAG_OFFSET    140
+
+static int get_boot_index(int entries)
+{
+    return 0; /* Implemented next patch */
+}
+
+static void zipl_println(const char *data, size_t len)
+{
+    char buf[len + 2];
+
+    ebcdic_to_ascii(data, buf, len);
+    buf[len] = '\n';
+    buf[len + 1] = '\0';
+
+    sclp_print(buf);
+}
+
 int menu_get_zipl_boot_index(const void *stage2, int offset)
 {
-    return 0; /* implemented next patch */
+    const char *data = stage2 + offset;
+    uint16_t zipl_flag = *(uint16_t *)(data - ZIPL_FLAG_OFFSET);
+    uint16_t zipl_timeout = *(uint16_t *)(data - ZIPL_TIMEOUT_OFFSET);
+    size_t len;
+    int ct;
+
+    if (flags & BOOT_MENU_FLAG_ZIPL_OPTS) {
+        if (!zipl_flag) {
+            return 0; /* Boot default */
+        }
+        timeout = zipl_timeout;
+    }
+
+    /* Print and count all menu items, including the banner */
+    for (ct = 0; *data; ct++) {
+        len = strlen(data);
+        zipl_println(data, len);
+        data += len + 1;
+
+        if (ct < 2) {
+            sclp_print("\n");
+        }
+    }
+
+    sclp_print("\n");
+
+    return get_boot_index(ct - 1);
 }
 
 void menu_set_parms(uint8_t boot_menu_flag, uint16_t boot_menu_timeout)
-- 
2.7.4