Re: [kvm-unit-tests PATCH 1/2] s390x: smp: Use full PSW to bringup new cpu

Janosch Frank
2019-12-11T12:35:10Z

[-- Attachment #1.1: Type: text/plain, Size: 1671 bytes --]

On 12/11/19 1:31 PM, David Hildenbrand wrote:
> On 11.12.19 12:59, Janosch Frank wrote:
>> Up to now we ignored the psw mask and only used the psw address when
>> bringing up a new cpu. For DAT we need to also load the mask, so let's
>> do that.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>> lib/s390x/smp.c | 2 ++
>> s390x/cstart64.S | 2 +-
>> 2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
>> index f57f420..e17751a 100644
>> --- a/lib/s390x/smp.c
>> +++ b/lib/s390x/smp.c
>> @@ -185,6 +185,8 @@ int smp_cpu_setup(uint16_t addr, struct psw psw)
>> cpu->stack = (uint64_t *)alloc_pages(2);
>>
>> /* Start without DAT and any other mask bits. */
>> + cpu->lowcore->sw_int_psw.mask = psw.mask;
>> + cpu->lowcore->sw_int_psw.addr = psw.addr;
>> cpu->lowcore->sw_int_grs[14] = psw.addr;
>
> Not looking at the code (sorry :D ), do we still need this then? (you
> drop the br bewlo)

r14 is the return address, saving/initialising it doesn't sound like a
bad idea to me. If we ever have stack traces, it might show up, or won't it?

>
>> cpu->lowcore->sw_int_grs[15] = (uint64_t)cpu->stack + (PAGE_SIZE * 4);
>> lc->restart_new_psw.mask = 0x0000000180000000UL;
>> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
>> index 86dd4c4..e6a6bdb 100644
>> --- a/s390x/cstart64.S
>> +++ b/s390x/cstart64.S
>> @@ -159,7 +159,7 @@ smp_cpu_setup_state:
>> xgr %r1, %r1
>> lmg %r0, %r15, GEN_LC_SW_INT_GRS
>> lctlg %c0, %c0, GEN_LC_SW_INT_CRS
>> - br %r14
>> + lpswe GEN_LC_SW_INT_PSW
>>
>> pgm_int:
>> SAVE_REGS
>>
>
>

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]