[PATCH v17 22/34] pc-bios/s390-ccw: Introduce ZiplBootMode enum for IPL mode selection

Add ZiplBootMode enumeration to support multiple IPL boot configurations.
Boot modes differentiate between normal boot and secure IPL operations,
enabled based on boot certificates specified via the boot-certs option.

Normal Mode: IPL when no certificates are provided. No signature
verification is performed.

This prepares for future secure IPL modes requiring signature
verification.

Signed-off-by: Zhuoying Cai <[email protected]>
Reviewed-by: Collin Walling <[email protected]>
Reviewed-by: Jared Rossi <[email protected]>
---
 docs/system/s390x/secure-ipl.rst | 21 +++++++++++++++++++++
 pc-bios/s390-ccw/bootmap.c       | 16 +++++++++++++++-
 pc-bios/s390-ccw/main.c          |  6 ++++++
 pc-bios/s390-ccw/s390-ccw.h      |  6 ++++++
 4 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/docs/system/s390x/secure-ipl.rst b/docs/system/s390x/secure-ipl.rst
index 88df52ce2f..9d7d33f5ed 100644
--- a/docs/system/s390x/secure-ipl.rst
+++ b/docs/system/s390x/secure-ipl.rst
@@ -18,3 +18,24 @@ Note: certificate files must have a .pem extension.
 .. code-block:: shell
 
     qemu-system-s390x -machine s390-ccw-virtio,boot-certs.0.path=/.../qemu/certs,boot-certs.1.path=/another/path/cert.pem ...
+
+
+IPL Modes
+---------
+
+Multiple IPL modes are available to differentiate between the various IPL
+configurations. These modes are mutually exclusive and enabled based on the
+``boot-certs`` option on the QEMU command line.
+
+Normal Mode
+^^^^^^^^^^^
+
+The absence of certificates will attempt to IPL a guest without secure IPL
+operations. No checks are performed, and no warnings/errors are reported.
+This is the default mode.
+
+Configuration:
+
+.. code-block:: shell
+
+    qemu-system-s390x -machine s390-ccw-virtio ...
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 4dab0fd15c..642934eebd 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -330,6 +330,9 @@ static int run_eckd_boot_script(block_number_t bmt_block_nr,
     /* The S1B block number is NULL_BLOCK_NR if and only if it's an LD-IPL */
     bool ldipl = (s1b_block_nr == NULL_BLOCK_NR);
 
+    IPL_assert((boot_mode == ZIPL_BOOT_MODE_NORMAL),
+                "Secure boot with the ECKD scheme is not supported!");
+
     if (menu_is_enabled_zipl() && !ldipl) {
         loadparm = eckd_get_boot_menu_index(s1b_block_nr);
     }
@@ -729,7 +732,14 @@ static int zipl_run(ScsiBlockPtr *pte)
     /* Load image(s) into RAM */
     entry = (ComponentEntry *)(&header[1]);
 
-    rc = zipl_run_normal(&entry, tmp_sec);
+    switch (boot_mode) {
+    case ZIPL_BOOT_MODE_NORMAL:
+        rc = zipl_run_normal(&entry, tmp_sec);
+        break;
+    default:
+        panic("Unknown boot mode");
+    }
+
     if (rc) {
         return rc;
     }
@@ -1100,12 +1110,16 @@ void zipl_load(void)
     VDev *vdev = virtio_get_device();
 
     if (vdev->is_cdrom) {
+        IPL_assert((boot_mode == ZIPL_BOOT_MODE_NORMAL),
+                   "Secure boot from ISO image is not supported!");
         ipl_iso_el_torito();
         puts("Failed to IPL this ISO image!");
         return;
     }
 
     if (virtio_get_device_type() == VIRTIO_ID_NET) {
+        IPL_assert((boot_mode == ZIPL_BOOT_MODE_NORMAL),
+                    "Virtio net boot device does not support secure boot!");
         netmain();
         puts("Failed to IPL from this network!");
         return;
diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index 44888e0c5c..40e568fc71 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -30,6 +30,7 @@ IplParameterBlock *iplb;
 bool have_iplb;
 static uint16_t cutype;
 LowCore *lowcore; /* Yes, this *is* a pointer to address 0 */
+ZiplBootMode boot_mode;
 
 #define LOADPARM_PROMPT "PROMPT  "
 #define LOADPARM_EMPTY  "        "
@@ -306,6 +307,9 @@ static void ipl_ccw_device(void)
     switch (cutype) {
     case CU_TYPE_DASD_3990:
     case CU_TYPE_DASD_2107:
+        IPL_assert((boot_mode == ZIPL_BOOT_MODE_NORMAL),
+                    "Passthrough (vfio) CCW device does not support secure boot!");
+
         dasd_ipl(blk_schid, cutype);
         break;
     case CU_TYPE_VIRTIO:
@@ -393,6 +397,8 @@ void main(void)
         probe_boot_device();
     }
 
+    boot_mode = ZIPL_BOOT_MODE_NORMAL;
+
     while (have_iplb) {
         boot_setup();
         if (have_iplb && find_boot_device()) {
diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index 1e1f71775e..5420443ad2 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -69,6 +69,12 @@ int sclp_read(char *str, size_t count);
 /* bootmap.c */
 void zipl_load(void);
 
+typedef enum ZiplBootMode {
+    ZIPL_BOOT_MODE_NORMAL = 0,
+} ZiplBootMode;
+
+extern ZiplBootMode boot_mode;
+
 /* jump2ipl.c */
 void write_reset_psw(uint64_t psw);
 int jump_to_IPL_code(uint64_t address);
-- 
2.55.0