target-s390: add firmware code

This patch adds a firmware blob to the S390 target. The blob is a simple
implementation of a virtio client that tries to read the second stage
bootloader from sectors described as of offset 0x20 in the MBR.

In combination with an updated zipl this allows for booting from virtio
block devices. This firmware is built from the same sources as the second
stage bootloader. You can find a virtio capable s390-tools in this repo:

git://repo.or.cz/s390-tools.git

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

Makefile

@@ -184,7 +184,8 @@ pxe-e1000.bin \
 pxe-ne2k_pci.bin pxe-pcnet.bin \
 pxe-rtl8139.bin pxe-virtio.bin \
 bamboo.dtb petalogix-s3adsp1800.dtb \
-multiboot.bin linuxboot.bin
+multiboot.bin linuxboot.bin \
+s390-zipl.rom
 else
 BLOBS=
 endif

hw/s390-virtio.c

@@ -52,6 +52,10 @@
 #define INITRD_PARM_SIZE                0x010410UL
 #define PARMFILE_START                  0x001000UL
 
+#define ZIPL_START			0x009000UL
+#define ZIPL_LOAD_ADDR			0x009000UL
+#define ZIPL_FILENAME			"s390-zipl.rom"
+
 #define MAX_BLK_DEVS                    10
 
 static VirtIOS390Bus *s390_bus;
@@ -188,6 +192,28 @@ static void s390_init(ram_addr_t ram_size,
 
         env->psw.addr = KERN_IMAGE_START;
         env->psw.mask = 0x0000000180000000ULL;
+    } else {
+        ram_addr_t bios_size = 0;
+        char *bios_filename;
+
+        /* Load zipl bootloader */
+        if (bios_name == NULL) {
+            bios_name = ZIPL_FILENAME;
+        }
+
+        bios_filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
+        bios_size = load_image(bios_filename, qemu_get_ram_ptr(ZIPL_LOAD_ADDR));
+
+        if ((long)bios_size < 0) {
+            hw_error("could not load bootloader '%s'\n", bios_name);
+        }
+
+        if (bios_size > 4096) {
+            hw_error("stage1 bootloader is > 4k\n");
+        }
+
+        env->psw.addr = ZIPL_START;
+        env->psw.mask = 0x0000000180000000ULL;
     }
 
     if (initrd_filename) {

pc-bios/README

@@ -27,3 +27,7 @@
   virtio 1af4:1000
 
   http://rom-o-matic.net/
+
+- The S390 zipl loader is an addition to the official IBM s390-tools
+  package. That fork is maintained in its own git repository at:
+  git://repo.or.cz/s390-tools.git