s390-bios: Use control unit type to determine boot method

The boot method is different depending on which device type we are
booting from. Let's examine the control unit type to determine if we're
a virtio device. We'll eventually add a case to check for a real dasd device
here as well.

Since we have to call enable_subchannel() in main now, might as well
remove that call from virtio.c : run_ccw(). This requires adding some
additional enable_subchannel calls to not break calls to
virtio_is_supported().

Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1554388475-18329-14-git-send-email-jjherne@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

3 files changed, 15 insertions, 3 deletions

diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
index d3a161c685..57a10138c6 100644
--- a/pc-bios/s390-ccw/main.c
+++ b/pc-bios/s390-ccw/main.c
@@ -76,6 +76,7 @@ static bool find_subch(int dev_no)
         /* Skip net devices since no IPLB is created and therefore no
          * network bootloader has been loaded
          */
+        enable_subchannel(blk_schid);
         if (virtio_is_supported(blk_schid) &&
             virtio_get_device_type() == VIRTIO_ID_NET && dev_no < 0) {
             continue;
@@ -198,13 +199,24 @@ static void virtio_setup(void)
 
 int main(void)
 {
+    uint16_t cutype;
+
     sclp_setup();
     css_setup();
     boot_setup();
     find_boot_device();
+    enable_subchannel(blk_schid);
 
-    virtio_setup();
-    zipl_load(); /* no return */
+    cutype = cu_type(blk_schid);
+    switch (cutype) {
+    case CU_TYPE_VIRTIO:
+        virtio_setup();
+        zipl_load(); /* no return */
+        break;
+    default:
+        print_int("Attempting to boot from unexpected device type", cutype);
+        panic("");
+    }
 
     panic("Failed to load OS from hard disk\n");
     return 0; /* make compiler happy */
diff --git a/pc-bios/s390-ccw/netmain.c b/pc-bios/s390-ccw/netmain.c
index 5189c0fc39..f3542cb2cf 100644
--- a/pc-bios/s390-ccw/netmain.c
+++ b/pc-bios/s390-ccw/netmain.c
@@ -476,6 +476,7 @@ static bool find_net_dev(Schib *schib, int dev_no)
         if (!schib->pmcw.dnv) {
             continue;
         }
+        enable_subchannel(net_schid);
         if (!virtio_is_supported(net_schid)) {
             continue;
         }
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 35278eaee1..fb40ca9828 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -102,7 +102,6 @@ static int run_ccw(VDev *vdev, int cmd, void *ptr, int len, bool sli)
         ccw.flags |= CCW_FLAG_SLI;
     }
 
-    enable_subchannel(vdev->schid);
     return do_cio(vdev->schid, vdev->senseid.cu_type, ptr2u32(&ccw), CCW_FMT1);
 }