On Tue, 28 Jul 2020 20:37:33 +0200 Thomas Huth <th...@redhat.com> wrote:
> If no boot device has been specified (via "bootindex=..."), the > s390-ccw bios scans through all devices to find a bootable device. maybe a better title for the patch is "scan through all devices if no boot device specified" then, since it seems we will scan all devices, not just "boot" devices? > But so far, it stops at the very first block device (including > virtio-scsi controllers without attached devices) that it finds, no > matter whether it is bootable or not. That leads to some weird > situatation where it is e.g. possible to boot via: > > qemu-system-s390x -hda /path/to/disk.qcow2 > > but not if there is e.g. a virtio-scsi controller specified before: > > qemu-system-s390x -device virtio-scsi -hda /path/to/disk.qcow2 > > While using "bootindex=..." is clearly the preferred way of booting > on s390x, we still can make the life for the users at least a little > bit easier if we look at all available devices to find a bootable one. > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1846975 > Signed-off-by: Thomas Huth <th...@redhat.com> > --- > pc-bios/s390-ccw/main.c | 46 > +++++++++++++++++++++++++++-------------- 1 file changed, 31 > insertions(+), 15 deletions(-) > > diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c > index 3cd01cd80f..0af872f9e3 100644 > --- a/pc-bios/s390-ccw/main.c > +++ b/pc-bios/s390-ccw/main.c > @@ -182,20 +182,8 @@ static void boot_setup(void) > static void find_boot_device(void) > { > VDev *vdev = virtio_get_device(); > - int ssid; > bool found; > > - if (!have_iplb) { > - for (ssid = 0; ssid < 0x3; ssid++) { > - blk_schid.ssid = ssid; > - found = find_subch(-1); > - if (found) { > - return; > - } > - } > - panic("Could not find a suitable boot device (none > specified)\n"); > - } > - > switch (iplb.pbt) { > case S390_IPL_TYPE_CCW: > debug_print_int("device no. ", iplb.ccw.devno); > @@ -260,14 +248,42 @@ static void ipl_boot_device(void) > } > } > > +/* > + * No boot device has been specified, so we have to scan through the > + * channels to find one. > + */ > +static void probe_boot_device(void) > +{ > + int ssid, sch_no, ret; > + > + for (ssid = 0; ssid < 0x3; ssid++) { > + blk_schid.ssid = ssid; > + for (sch_no = 0; sch_no < 0x10000; sch_no++) { > + ret = check_sch_no(-1, sch_no); > + if (ret < 0) { > + break; > + } > + if (ret == true) { > + ipl_boot_device(); /* Only returns if > unsuccessful */ > + } > + } > + } > + > + sclp_print("Could not find a suitable boot device (none > specified)\n"); +} > + > int main(void) > { > sclp_setup(); > css_setup(); > boot_setup(); > - find_boot_device(); > - enable_subchannel(blk_schid); > - ipl_boot_device(); > + if (have_iplb) { > + find_boot_device(); > + enable_subchannel(blk_schid); > + ipl_boot_device(); > + } else { > + probe_boot_device(); > + } > > panic("Failed to load OS from hard disk\n"); > return 0; /* make compiler happy */
