Also adding QEMU.
On 06/25/2018 09:10 AM, Christian Borntraeger wrote:
>
>
> On 06/22/2018 09:47 PM, Guenter Roeck wrote:
>> Hi,
>>
>> starting with commit 's390/boot: make head.S and als.c be part of the
>> decompressor only' in -next, s390 immages no longer boot in qemu.
>> As far as I can see, the reason is that the command line is no longer
>> passed from qemu to the kernel, which results in a panic because the
>> root file system can not be mounted.
>>
>> Was this change made on purpose ? If so, is there a way to get qemu
>> back to working ?
>
> Certainly not on purpose.
>
> Vasily, I can reproduce this with KVM and an external kernel boot of the vmlinux file (the elf file)
>
> e.g.
>
> qemu-system-s390 -enable-kvm -nographic -kernel vmlinux -append "this string no longer is command line"
>
> The compressed image (bzImage) seems to work fine though.
>
> This seems to be an unfortunate side effect of QEMUs ways to "guess" its Linux (checking for start
> address 0x10000, which is no longer true for the vmlinux file). With the pure vmlinux elf file
> the load address is 0x100000 as there is no unpacker.
>
> Guenter, can you check if arch/s390/boot/bzImage works for you as a workaround?
Something like this in QEMU
diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index f278036fa7..14153ce880 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -187,11 +187,13 @@ static void s390_ipl_realize(DeviceState *dev, Error **errp)
*/
if (pentry == KERN_IMAGE_START || pentry == 0x800) {
ipl->start_addr = KERN_IMAGE_START;
- /* Overwrite parameters in the kernel image, which are "rom" */
- strcpy(rom_ptr(KERN_PARM_AREA), ipl->cmdline);
} else {
ipl->start_addr = pentry;
}
+ if (ipl->cmdline) {
+ /* If there is a command line, put it in the right place */
+ strcpy(rom_ptr(KERN_PARM_AREA), ipl->cmdline);
+ }
if (ipl->initrd) {
ram_addr_t initrd_offset;
would put the command line in no matter what the start address is.
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