On 22.02.2018 05:40, Thomas Huth wrote:
> On 21.02.2018 20:35, Collin L. Walling wrote:
>> The s390-ccw firmware needs some information in support of the
>> boot process which is not available on the native machine.
>> Examples are the netboot firmware load address and now the
>> boot menu parameters.
>>
>> While storing that data in unused fields of the IPL parameter block
>> works, that approach could create problems if the parameter block
>> definition should change in the future. Because then a guest could
>> overwrite these fields using the set IPLB diagnose.
>>
>> In fact the data in question is of more global nature and not really
>> tied to an IPL device, so separating it is rather logical.
>>
>> This commit introduces a new structure to hold firmware relevant
>> IPL parameters set by QEMU. The data is stored at location 204 (dec)
>> and can contain up to 7 32-bit words. This area is available to
>> programming in the z/Architecture Principles of Operation and
>> can thus safely be used by the firmware until the IPL has completed.
>>
>> Signed-off-by: Viktor Mihajlovski
>> Signed-off-by: Collin L. Walling
>> ---
>> hw/s390x/ipl.c | 18 +-
>> hw/s390x/ipl.h | 25 +++--
>> pc-bios/s390-ccw/iplb.h | 18 --
>> pc-bios/s390-ccw/main.c | 6 +-
>> 4 files changed, 61 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
>> index 0d06fc1..79f5a58 100644
>> --- a/hw/s390x/ipl.c
>> +++ b/hw/s390x/ipl.c
>> @@ -399,6 +399,21 @@ void s390_reipl_request(void)
>> qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
>> }
>>
>> +static void s390_ipl_prepare_qipl(S390CPU *cpu)
>> +{
>> +S390IPLState *ipl = get_ipl_device();
>> +uint8_t *addr;
>> +uint64_t len = 4096;
>> +
>> +addr = cpu_physical_memory_map(cpu->env.psa, &len, 1);
>> +if (!addr || len < QIPL_ADDRESS + sizeof(QemuIplParameters)) {
>> +error_report("Cannot set QEMU IPL parameters");
>> +return;
>> +}
>> +memcpy(addr + QIPL_ADDRESS, &ipl->qipl, sizeof(QemuIplParameters));
>> +cpu_physical_memory_unmap(addr, len, 1, len);
>> +}
>> +
>> void s390_ipl_prepare_cpu(S390CPU *cpu)
>> {
>> S390IPLState *ipl = get_ipl_device();
>> @@ -418,8 +433,9 @@ void s390_ipl_prepare_cpu(S390CPU *cpu)
>> error_report_err(err);
>> vm_stop(RUN_STATE_INTERNAL_ERROR);
>> }
>> -ipl->iplb.ccw.netboot_start_addr = cpu_to_be64(ipl->start_addr);
>> +ipl->qipl.netboot_start_addr = cpu_to_be64(ipl->start_addr);
>> }
>> +s390_ipl_prepare_qipl(cpu);
>> }
>>
>> static void s390_ipl_reset(DeviceState *dev)
>> diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
>> index 8a705e0..08926a3 100644
>> --- a/hw/s390x/ipl.h
>> +++ b/hw/s390x/ipl.h
>> @@ -16,8 +16,7 @@
>> #include "cpu.h"
>>
>> struct IplBlockCcw {
>> -uint64_t netboot_start_addr;
>> -uint8_t reserved0[77];
>> +uint8_t reserved0[85];
>> uint8_t ssid;
>> uint16_t devno;
>> uint8_t vm_flags;
>> @@ -90,6 +89,27 @@ void s390_ipl_prepare_cpu(S390CPU *cpu);
>> IplParameterBlock *s390_ipl_get_iplb(void);
>> void s390_reipl_request(void);
>>
>> +#define QIPL_ADDRESS 0xcc
>> +
>> +/*
>> + * The QEMU IPL Parameters will be stored at absolute address
>> + * 204 (0xcc) which means it is 32-bit word aligned but not
>> + * double-word aligned.
>> + * Placement of data fields in this area must account for
>> + * their alignment needs. E.g., netboot_start_address must
>> + * have an offset of n * 8 bytes within the struct in order
>> + * to keep it double-word aligned.
>
> Should that rather be "4 + n * 8" instead of "n * 8" ?
I wonder if I ever get that comment right. You're correct of course.
>
> Apart from that, patch looks good to me now, so once you've fixed the
> comment (if necessary):
>
> Reviewed-by: Thomas Huth
>
--
Regards,
Viktor Mihajlovski