pc-bios/s390-ccw: Allow booting in case the first virtio-blk disk is bad

If you try to boot with two virtio-blk disks (without bootindex), and
only the second one is bootable, the s390-ccw bios currently stops at
the first disk and does not continue booting from the second one. This
is annoying - and all other major QEMU firmwares succeed to boot from
the second disk in this case, so we should do the same in the s390-ccw
bios, too.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20200806105349.632-8-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

2 files changed, 24 insertions, 12 deletions

diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 9720567..0ef6b85 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -289,11 +289,18 @@ static void ipl_eckd_cdl(void)
     read_block(1, ipl2, "Cannot read IPL2 record at block 1");
 
     mbr = &ipl2->mbr;
-    IPL_assert(magic_match(mbr, ZIPL_MAGIC), "No zIPL section in IPL2 record.");
-    IPL_assert(block_size_ok(mbr->blockptr.xeckd.bptr.size),
-               "Bad block size in zIPL section of IPL2 record.");
-    IPL_assert(mbr->dev_type == DEV_TYPE_ECKD,
-               "Non-ECKD device type in zIPL section of IPL2 record.");
+    if (!magic_match(mbr, ZIPL_MAGIC)) {
+        sclp_print("No zIPL section in IPL2 record.\n");
+        return;
+    }
+    if (!block_size_ok(mbr->blockptr.xeckd.bptr.size)) {
+        sclp_print("Bad block size in zIPL section of IPL2 record.\n");
+        return;
+    }
+    if (!mbr->dev_type == DEV_TYPE_ECKD) {
+        sclp_print("Non-ECKD device type in zIPL section of IPL2 record.\n");
+        return;
+    }
 
     /* save pointer to Boot Map Table */
     bmt_block_nr = eckd_block_num(&mbr->blockptr.xeckd.bptr.chs);
@@ -303,10 +310,14 @@ static void ipl_eckd_cdl(void)
 
     memset(sec, FREE_SPACE_FILLER, sizeof(sec));
     read_block(2, vlbl, "Cannot read Volume Label at block 2");
-    IPL_assert(magic_match(vlbl->key, VOL1_MAGIC),
-               "Invalid magic of volume label block");
-    IPL_assert(magic_match(vlbl->f.key, VOL1_MAGIC),
-               "Invalid magic of volser block");
+    if (!magic_match(vlbl->key, VOL1_MAGIC)) {
+        sclp_print("Invalid magic of volume label block.\n");
+        return;
+    }
+    if (!magic_match(vlbl->f.key, VOL1_MAGIC)) {
+        sclp_print("Invalid magic of volser block.\n");
+        return;
+    }
     print_volser(vlbl->f.volser);
 
     run_eckd_boot_script(bmt_block_nr, s1b_block_nr);
@@ -398,7 +409,8 @@ static void ipl_eckd(void)
     read_block(0, mbr, "Cannot read block 0 on DASD");
 
     if (magic_match(mbr->magic, IPL1_MAGIC)) {
-        ipl_eckd_cdl(); /* no return */
+        ipl_eckd_cdl();         /* only returns in case of error */
+        return;
     }
 
     /* LDL/CMS? */
@@ -825,5 +837,5 @@ void zipl_load(void)
         panic("\n! Unknown IPL device type !\n");
     }
 
-    panic("\n* this can never happen *\n");
+    sclp_print("zIPL load failed.\n");
 }
diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index 9b58107..fc17e6a 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -240,7 +240,7 @@ static void ipl_boot_device(void)
         break;
     case CU_TYPE_VIRTIO:
         if (virtio_setup() == 0) {
-            zipl_load(); /* no return */
+            zipl_load();             /* Only returns in case of errors */
         }
         break;
     default: