pc-bios/s390x: Enable multi-device boot loop

Allow attempts to boot from multiple IPL devices. If the first device fails to
IPL, select the pre-built IPLB for the next device in the boot order and attempt
to IPL from it. Continue this process until IPL is successful or there are no
devices left to try.

Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20241020012953.1380075-18-jrossi@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

pc-bios/s390-ccw/iplb.h

@@ -17,9 +17,11 @@
 #endif
 
 #include <qipl.h>
+#include <string.h>
 
 extern QemuIplParameters qipl;
 extern IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
+extern bool have_iplb;
 
 #define S390_IPL_TYPE_FCP 0x00
 #define S390_IPL_TYPE_CCW 0x02
@@ -49,4 +51,26 @@ static inline bool set_iplb(IplParameterBlock *iplb)
     return manage_iplb(iplb, false);
 }
 
+/*
+ * The IPL started on the device, but failed in some way.  If the IPLB chain
+ * still has more devices left to try, use the next device in order.
+ */
+static inline bool load_next_iplb(void)
+{
+    IplParameterBlock *next_iplb;
+
+    if (qipl.chain_len < 1) {
+        return false;
+    }
+
+    qipl.index++;
+    next_iplb = (IplParameterBlock *) qipl.next_iplb;
+    memcpy(&iplb, next_iplb, sizeof(IplParameterBlock));
+
+    qipl.chain_len--;
+    qipl.next_iplb = qipl.next_iplb + sizeof(IplParameterBlock);
+
+    return true;
+}
+
 #endif /* IPLB_H */

pc-bios/s390-ccw/jump2ipl.c

@@ -45,9 +45,10 @@ int jump_to_IPL_code(uint64_t address)
      */
     if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) {
         iplb.devno = qipl.index;
-        if (!set_iplb(&iplb)) {
-            panic("Failed to set IPLB");
-        }
+    }
+
+    if (have_iplb && !set_iplb(&iplb)) {
+        panic("Failed to set IPLB");
     }
 
     /*

pc-bios/s390-ccw/main.c

@@ -23,7 +23,7 @@ static SubChannelId blk_schid = { .one = 1 };
 static char loadparm_str[LOADPARM_LEN + 1];
 QemuIplParameters qipl;
 IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
-static bool have_iplb;
+bool have_iplb;
 static uint16_t cutype;
 LowCore *lowcore; /* Yes, this *is* a pointer to address 0 */
 
@@ -55,6 +55,12 @@ void write_iplb_location(void)
     }
 }
 
+static void copy_qipl(void)
+{
+    QemuIplParameters *early_qipl = (QemuIplParameters *)QIPL_ADDRESS;
+    memcpy(&qipl, early_qipl, sizeof(QemuIplParameters));
+}
+
 unsigned int get_loadparm_index(void)
 {
     return atoi(loadparm_str);
@@ -152,6 +158,7 @@ static void menu_setup(void)
 
     /* If loadparm was set to any other value, then do not enable menu */
     if (memcmp(loadparm_str, LOADPARM_EMPTY, LOADPARM_LEN) != 0) {
+        menu_set_parms(qipl.qipl_flags & ~BOOT_MENU_FLAG_MASK, 0);
         return;
     }
 
@@ -183,7 +190,6 @@ static void css_setup(void)
 static void boot_setup(void)
 {
     char lpmsg[] = "LOADPARM=[________]\n";
-    have_iplb = store_iplb(&iplb);
 
     if (memcmp(iplb.loadparm, NO_LOADPARM, LOADPARM_LEN) != 0) {
         ebcdic_to_ascii((char *) iplb.loadparm, loadparm_str, LOADPARM_LEN);
@@ -191,6 +197,10 @@ static void boot_setup(void)
         sclp_get_loadparm_ascii(loadparm_str);
     }
 
+    if (have_iplb) {
+        menu_setup();
+    }
+
     memcpy(lpmsg + 10, loadparm_str, 8);
     puts(lpmsg);
 
@@ -208,6 +218,7 @@ static bool find_boot_device(void)
 
     switch (iplb.pbt) {
     case S390_IPL_TYPE_CCW:
+        vdev->scsi_device_selected = false;
         debug_print_int("device no. ", iplb.ccw.devno);
         blk_schid.ssid = iplb.ccw.ssid & 0x3;
         debug_print_int("ssid ", blk_schid.ssid);
@@ -231,15 +242,8 @@ static bool find_boot_device(void)
 static int virtio_setup(void)
 {
     VDev *vdev = virtio_get_device();
-    QemuIplParameters *early_qipl = (QemuIplParameters *)QIPL_ADDRESS;
     int ret;
 
-    memcpy(&qipl, early_qipl, sizeof(QemuIplParameters));
-
-    if (have_iplb) {
-        menu_setup();
-    }
-
     switch (vdev->senseid.cu_model) {
     case VIRTIO_ID_NET:
         puts("Network boot device detected");
@@ -271,10 +275,9 @@ static void ipl_boot_device(void)
         dasd_ipl(blk_schid, cutype);
         break;
     case CU_TYPE_VIRTIO:
-        if (virtio_setup()) {
-            return;    /* Only returns in case of errors */
+        if (virtio_setup() == 0) {
+            zipl_load();
         }
-        zipl_load();
         break;
     default:
         printf("Attempting to boot from unexpected device type 0x%X\n", cutype);
@@ -307,14 +310,22 @@ static void probe_boot_device(void)
 
 void main(void)
 {
+    copy_qipl();
     sclp_setup();
     css_setup();
-    boot_setup();
-    if (have_iplb && find_boot_device()) {
-        ipl_boot_device();
-    } else {
+    have_iplb = store_iplb(&iplb);
+    if (!have_iplb) {
         probe_boot_device();
     }
 
-    panic("Failed to IPL. Halting...");
+    while (have_iplb) {
+        boot_setup();
+        if (have_iplb && find_boot_device()) {
+            ipl_boot_device();
+        }
+        have_iplb = load_next_iplb();
+    }
+
+    panic("No suitable device for IPL. Halting...");
+
 }

pc-bios/s390-ccw/netmain.c

@@ -478,7 +478,7 @@ static bool virtio_setup(void)
      */
     enable_mss_facility();
 
-    if (store_iplb(&iplb)) {
+    if (have_iplb || store_iplb(&iplb)) {
         IPL_assert(iplb.pbt == S390_IPL_TYPE_CCW, "IPL_TYPE_CCW expected");
         dev_no = iplb.ccw.devno;
         debug_print_int("device no. ", dev_no);