Re: [Qemu-devel] [PATCH v1 1/8] s390x/tcg: factor out and fix DATA exception injection

[David Hildenbrand]

On 22.08.2018 18:52, David Hildenbrand wrote:
> On 22.08.2018 18:31, Richard Henderson wrote:
>> On 08/22/2018 12:57 AM, David Hildenbrand wrote:
>>> The DXC is to be stored in the low core, and only in the FPC in case AFP
>>> is enabled in CR0.
>>>
>>> Signed-off-by: David Hildenbrand <address@hidden>
>>> ---
>>>  target/s390x/cpu.h         |  1 +
>>>  target/s390x/excp_helper.c | 28 ++++++++++++++++++++++++++++
>>>  target/s390x/fpu_helper.c  | 13 +++----------
>>>  target/s390x/helper.h      |  1 +
>>>  target/s390x/tcg_s390x.h   |  2 ++
>>>  target/s390x/translate.c   | 19 +++++++++----------
>>>  6 files changed, 44 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
>>> index 6f8861e554..5e50c3a303 100644
>>> --- a/target/s390x/cpu.h
>>> +++ b/target/s390x/cpu.h
>>> @@ -322,6 +322,7 @@ extern const struct VMStateDescription vmstate_s390_cpu;
>>>  #define CR0_LOWPROT             0x0000000010000000ULL
>>>  #define CR0_SECONDARY           0x0000000004000000ULL
>>>  #define CR0_EDAT                0x0000000000800000ULL
>>> +#define CR0_AFP                 0x0000000000040000ULL
>>>  #define CR0_EMERGENCY_SIGNAL_SC 0x0000000000004000ULL
>>>  #define CR0_EXTERNAL_CALL_SC    0x0000000000002000ULL
>>>  #define CR0_CKC_SC              0x0000000000000800ULL
>>> diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
>>> index f0ce60cff2..f5cab94ec5 100644
>>> --- a/target/s390x/excp_helper.c
>>> +++ b/target/s390x/excp_helper.c
>>> @@ -21,11 +21,13 @@
>>>  #include "qemu/osdep.h"
>>>  #include "cpu.h"
>>>  #include "internal.h"
>>> +#include "exec/helper-proto.h"
>>>  #include "qemu/timer.h"
>>>  #include "exec/exec-all.h"
>>>  #include "exec/cpu_ldst.h"
>>>  #include "hw/s390x/ioinst.h"
>>>  #include "exec/address-spaces.h"
>>> +#include "tcg_s390x.h"
>>>  #ifndef CONFIG_USER_ONLY
>>>  #include "sysemu/sysemu.h"
>>>  #include "hw/s390x/s390_flic.h"
>>> @@ -48,6 +50,32 @@
>>>      do { } while (0)
>>>  #endif
>>>  
>>> +void QEMU_NORETURN tcg_s390_data_exception(CPUS390XState *env, uint32_t 
>>> dxc,
>>> +                                           uintptr_t ra)
>>> +{
>>> +    CPUState *cs = CPU(s390_env_get_cpu(env));
>>> +
>>> +    g_assert(!(dxc & ~0xff));
>>> +#if !defined(CONFIG_USER_ONLY)
>>> +    /* Store the DXC into the lowcore */
>>> +    stw_phys(cs->as, env->psa + offsetof(LowCore, data_exc_code), dxc);
>>> +#endif
>>> +
>>> +    /* Store the DXC into the FPC if AFP is enabled */
>>> +    if (env->cregs[0] & CR0_AFP) {
>>> +        env->fpc = (env->fpc & ~0xff00) | (dxc << 8);
>>> +    }
>>> +    s390_program_interrupt(env, PGM_DATA, ILEN_AUTO, ra);
>>
>> We should probably export tcg_s390_program_interrupt, so ...
>>
>>> +
>>> +    /* the following is not necessary, but allows us to use noreturn */
>>> +    cpu_loop_exit_restore(cs, ra);
>>
>> ... you don't have to do this.
>> But even if not, g_assert_not_reached() is better here.
> 
> If that also works, fine.
> 
>>
>> I'll note that s390_program_interrupt is buggy for tcg, in that it logs
>> env->psw.addr before cpu_loop_restore, and therefore psw.addr is essentially
>> random data.
> 
> Indeed, for that it works fairly reliably.


... just realized that it is really only about logging.

> 
> I'll send a fix with the next version.
> 
> Thanks!
> 
>>
>>
>> r~
>>
> 
> 


-- 

Thanks,

David / dhildenb