Re: [Qemu-devel] [PATCH 03/10] S390: Check Bootdevice Type

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 26/04/13 17:22, Alexander Graf wrote:
> 
> On 26.04.2013, at 14:12, Dominik Dingel wrote:
> 
>> Check for a kernel IPL entry and load kernel image if one was
>> specified.
>> If no kernel image was supplied and the first boot device
>> is not a virtio-ccw-blk device, print error message and exit.
>>
>> In case it is a virtio-ccw-blk device store the dev_no in reg[7]
> 
> I thought we want a boot order, not a singular device to boot off of?
> 
> Alex

First of all we want to be able to choose a boot device as a first step.
With this patch the user is able to use libvirt and friends to choose the
disk to boot from.

The nice approach with this bios/ipl device is that we can update both
in lock-step so this reg7 interface is not an ABI.

So in a future version we actually could:
a: implement diag 308 subcode 5/6, which would enable /sys/devices/firmware/[ipl|reipl]
just like on z/VM or LPAR (this allows to reboot from a different device).
b: implement a list.

b looks  nice, but I actually prefer a for two reasons:
1. be closer to the real hw
2. predictability
but we can certainly discuss this.

So I suggest to go with this patch and implement later on what we
agree upon?

Christian

> 
>>
>> Signed-off-by: Christian Paro <cparo@us.ibm.com>
>> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
>>
>> diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
>> index ace5ff5..9758529 100644
>> --- a/hw/s390x/ipl.c
>> +++ b/hw/s390x/ipl.c
>> @@ -16,6 +16,8 @@
>> #include "elf.h"
>> #include "hw/loader.h"
>> #include "hw/sysbus.h"
>> +#include "hw/s390x/virtio-ccw.h"
>> +#include "hw/s390x/css.h"
>>
>> #define KERN_IMAGE_START                0x010000UL
>> #define KERN_PARM_AREA                  0x010480UL
>> @@ -56,14 +58,25 @@ typedef struct S390IPLState {
>>     char *firmware;
>> } S390IPLState;
>>
>> +static void s390_ipl_kernel(uint64_t pswaddr)
>> +{
>> +    S390CPU *cpu = S390_CPU(qemu_get_cpu(0));
>> +    CPUS390XState *env = &cpu->env;
>> +
>> +    env->psw.addr = pswaddr;
>> +    env->psw.mask = IPL_PSW_MASK;
>> +    s390_add_running_cpu(cpu);
>> +}
>>
>> -static void s390_ipl_cpu(uint64_t pswaddr)
>> +static void s390_ipl_from_disk(VirtIOBlkCcw *dev, uint64_t pswaddr)
>> {
>>     S390CPU *cpu = S390_CPU(qemu_get_cpu(0));
>>     CPUS390XState *env = &cpu->env;
>> +    VirtioCcwDevice *ccw_dev = &(dev->parent_obj);
>>
>>     env->psw.addr = pswaddr;
>>     env->psw.mask = IPL_PSW_MASK;
>> +    env->regs[7] = ccw_dev->sch->devno;
>>     s390_add_running_cpu(cpu);
>> }
>>
>> @@ -152,7 +165,18 @@ static void s390_ipl_reset(DeviceState *dev)
>> {
>>     S390IPLState *ipl = S390_IPL(dev);
>>
>> -    s390_ipl_cpu(ipl->start_addr);
>> +    if (ipl->kernel) {
>> +        return s390_ipl_kernel(ipl->start_addr);
>> +    }
>> +
>> +    DeviceState *boot_device = get_boot_device(0);
>> +    if (object_dynamic_cast(OBJECT(boot_device), TYPE_VIRTIO_BLK) != NULL) {
>> +        s390_ipl_from_disk(VIRTIO_BLK_CCW(boot_device->parent_obj.parent),
>> +                           ipl->start_addr);
>> +    } else {
>> +        fprintf(stderr, "qemu: s390x only supports boot from virtio-ccw-blk\n");
>> +        exit(1);
>> +    }
>> }
>>
>> static void s390_ipl_class_init(ObjectClass *klass, void *data)
>> -- 
>> 1.7.9.5
>>
>