* [PATCH v2] s390/cpacf: Unpoison instruction results
@ 2026-08-07 12:20 Ilya Leoshkevich
2026-08-13 14:06 ` Harald Freudenberger
0 siblings, 1 reply; 4+ messages in thread
From: Ilya Leoshkevich @ 2026-08-07 12:20 UTC (permalink / raw)
To: Harald Freudenberger, Holger Dengler, Heiko Carstens,
Vasily Gorbik, Alexander Gordeev
Cc: linux-s390, linux-kernel, Ilya Leoshkevich
Stop KMSAN from complaining about CPACF outputs being uninitialized.
Do not unpoison variable-length parameter blocks: mapping function
codes (like CPACF_KIMD_SHA_256) to lengths is ugly. Let the callers
handle this once need arises.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
v1: https://lore.kernel.org/linux-s390/20260806190223.3292580-1-iii@linux.ibm.com/
v1 -> v2: Unpoison outputs of more instructions (Sashiko).
arch/s390/include/asm/cpacf.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/s390/include/asm/cpacf.h b/arch/s390/include/asm/cpacf.h
index a83683169d98d..13d6a6344802a 100644
--- a/arch/s390/include/asm/cpacf.h
+++ b/arch/s390/include/asm/cpacf.h
@@ -301,6 +301,7 @@ static __always_inline void __cpacf_query(unsigned int opcode,
cpacf_mask_t *mask)
{
__cpacf_query_insn(opcode, mask, CPACF_FC_QUERY);
+ kmsan_unpoison_memory(mask, sizeof(*mask));
}
static __always_inline int __cpacf_check_opcode(unsigned int opcode)
@@ -370,6 +371,7 @@ static __always_inline int cpacf_query_func(unsigned int opcode,
static __always_inline void __cpacf_qai(unsigned int opcode, cpacf_qai_t *qai)
{
__cpacf_query_insn(opcode, qai, CPACF_FC_QUERY_AUTH_INFO);
+ kmsan_unpoison_memory(qai, sizeof(*qai));
}
/**
@@ -422,6 +424,7 @@ static inline int cpacf_km(unsigned long func, void *param,
[opc] "i" (CPACF_KM)
: "cc", "memory", "0", "1");
+ kmsan_unpoison_memory(dest, src_len - s.odd);
return src_len - s.odd;
}
@@ -454,6 +457,7 @@ static inline int cpacf_kmc(unsigned long func, void *param,
[opc] "i" (CPACF_KMC)
: "cc", "memory", "0", "1");
+ kmsan_unpoison_memory(dest, src_len - s.odd);
return src_len - s.odd;
}
@@ -587,6 +591,7 @@ static inline int cpacf_kmctr(unsigned long func, void *param, u8 *dest,
[opc] "i" (CPACF_KMCTR)
: "cc", "memory", "0", "1");
+ kmsan_unpoison_memory(dest, src_len - s.odd);
return src_len - s.odd;
}
@@ -619,6 +624,7 @@ static inline void cpacf_prno(unsigned long func, void *param,
: [fc] "d" (func), [pba] "d" ((unsigned long)param),
[seed] "d" (s.pair), [opc] "i" (CPACF_PRNO)
: "cc", "memory", "0", "1");
+ kmsan_unpoison_memory(dest, dest_len);
}
/**
@@ -731,6 +737,7 @@ static inline void cpacf_kma(unsigned long func, void *param, u8 *dest,
: [fc] "d" (func), [pba] "d" ((unsigned long)param),
[opc] "i" (CPACF_KMA)
: "cc", "memory", "0", "1");
+ kmsan_unpoison_memory(dest, src_len);
}
#endif /* _ASM_S390_CPACF_H */
--
2.55.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] s390/cpacf: Unpoison instruction results
2026-08-07 12:20 [PATCH v2] s390/cpacf: Unpoison instruction results Ilya Leoshkevich
@ 2026-08-13 14:06 ` Harald Freudenberger
2026-08-13 14:09 ` Ilya Leoshkevich
0 siblings, 1 reply; 4+ messages in thread
From: Harald Freudenberger @ 2026-08-13 14:06 UTC (permalink / raw)
To: Ilya Leoshkevich
Cc: Holger Dengler, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
linux-s390, linux-kernel
On 2026-08-07 14:20, Ilya Leoshkevich wrote:
> Stop KMSAN from complaining about CPACF outputs being uninitialized.
>
> Do not unpoison variable-length parameter blocks: mapping function
> codes (like CPACF_KIMD_SHA_256) to lengths is ugly. Let the callers
> handle this once need arises.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
> v1:
> https://lore.kernel.org/linux-s390/20260806190223.3292580-1-iii@linux.ibm.com/
> v1 -> v2: Unpoison outputs of more instructions (Sashiko).
>
See my comment below.
> arch/s390/include/asm/cpacf.h | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/s390/include/asm/cpacf.h
> b/arch/s390/include/asm/cpacf.h
> index a83683169d98d..13d6a6344802a 100644
> --- a/arch/s390/include/asm/cpacf.h
> +++ b/arch/s390/include/asm/cpacf.h
> @@ -301,6 +301,7 @@ static __always_inline void __cpacf_query(unsigned
> int opcode,
> cpacf_mask_t *mask)
> {
> __cpacf_query_insn(opcode, mask, CPACF_FC_QUERY);
> + kmsan_unpoison_memory(mask, sizeof(*mask));
> }
>
> static __always_inline int __cpacf_check_opcode(unsigned int opcode)
> @@ -370,6 +371,7 @@ static __always_inline int
> cpacf_query_func(unsigned int opcode,
> static __always_inline void __cpacf_qai(unsigned int opcode,
> cpacf_qai_t *qai)
> {
> __cpacf_query_insn(opcode, qai, CPACF_FC_QUERY_AUTH_INFO);
> + kmsan_unpoison_memory(qai, sizeof(*qai));
> }
>
> /**
> @@ -422,6 +424,7 @@ static inline int cpacf_km(unsigned long func, void
> *param,
> [opc] "i" (CPACF_KM)
> : "cc", "memory", "0", "1");
>
> + kmsan_unpoison_memory(dest, src_len - s.odd);
> return src_len - s.odd;
> }
>
> @@ -454,6 +457,7 @@ static inline int cpacf_kmc(unsigned long func,
> void *param,
> [opc] "i" (CPACF_KMC)
> : "cc", "memory", "0", "1");
>
> + kmsan_unpoison_memory(dest, src_len - s.odd);
> return src_len - s.odd;
> }
>
> @@ -587,6 +591,7 @@ static inline int cpacf_kmctr(unsigned long func,
> void *param, u8 *dest,
> [opc] "i" (CPACF_KMCTR)
> : "cc", "memory", "0", "1");
>
> + kmsan_unpoison_memory(dest, src_len - s.odd);
> return src_len - s.odd;
> }
>
> @@ -619,6 +624,7 @@ static inline void cpacf_prno(unsigned long func,
> void *param,
> : [fc] "d" (func), [pba] "d" ((unsigned long)param),
> [seed] "d" (s.pair), [opc] "i" (CPACF_PRNO)
> : "cc", "memory", "0", "1");
> + kmsan_unpoison_memory(dest, dest_len);
> }
>
> /**
> @@ -731,6 +737,7 @@ static inline void cpacf_kma(unsigned long func,
> void *param, u8 *dest,
> : [fc] "d" (func), [pba] "d" ((unsigned long)param),
> [opc] "i" (CPACF_KMA)
> : "cc", "memory", "0", "1");
> + kmsan_unpoison_memory(dest, src_len);
I am unhappy with this kma thing. This would only work properly with
CC 0. But CC 1 and 2 are not handled properly. However, I had a closer
look onto the AR for kma and ... well this inline function should
handle CC 1 and CC 2 somehow and it should similar to the other inline
functions return the number of bytes processed like for example
cpacf_km().
I'll open up a bugzilla to fix this kma inline function.
If you leave out this kma hunk you can add my R-b.
> }
>
> #endif /* _ASM_S390_CPACF_H */
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] s390/cpacf: Unpoison instruction results
2026-08-13 14:06 ` Harald Freudenberger
@ 2026-08-13 14:09 ` Ilya Leoshkevich
2026-08-13 15:51 ` Harald Freudenberger
0 siblings, 1 reply; 4+ messages in thread
From: Ilya Leoshkevich @ 2026-08-13 14:09 UTC (permalink / raw)
To: freude
Cc: Holger Dengler, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
linux-s390, linux-kernel
On 8/13/26 16:06, Harald Freudenberger wrote:
> On 2026-08-07 14:20, Ilya Leoshkevich wrote:
>> Stop KMSAN from complaining about CPACF outputs being uninitialized.
>>
>> Do not unpoison variable-length parameter blocks: mapping function
>> codes (like CPACF_KIMD_SHA_256) to lengths is ugly. Let the callers
>> handle this once need arises.
>>
>> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
>> ---
>> v1:
>> https://lore.kernel.org/linux-s390/20260806190223.3292580-1-
>> iii@linux.ibm.com/
>> v1 -> v2: Unpoison outputs of more instructions (Sashiko).
>>
>
> See my comment below.
>
>> arch/s390/include/asm/cpacf.h | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/s390/include/asm/cpacf.h b/arch/s390/include/asm/
>> cpacf.h
>> index a83683169d98d..13d6a6344802a 100644
>> --- a/arch/s390/include/asm/cpacf.h
>> +++ b/arch/s390/include/asm/cpacf.h
>> @@ -301,6 +301,7 @@ static __always_inline void __cpacf_query(unsigned
>> int opcode,
>> cpacf_mask_t *mask)
>> {
>> __cpacf_query_insn(opcode, mask, CPACF_FC_QUERY);
>> + kmsan_unpoison_memory(mask, sizeof(*mask));
>> }
>>
>> static __always_inline int __cpacf_check_opcode(unsigned int opcode)
>> @@ -370,6 +371,7 @@ static __always_inline int
>> cpacf_query_func(unsigned int opcode,
>> static __always_inline void __cpacf_qai(unsigned int opcode,
>> cpacf_qai_t *qai)
>> {
>> __cpacf_query_insn(opcode, qai, CPACF_FC_QUERY_AUTH_INFO);
>> + kmsan_unpoison_memory(qai, sizeof(*qai));
>> }
>>
>> /**
>> @@ -422,6 +424,7 @@ static inline int cpacf_km(unsigned long func,
>> void *param,
>> [opc] "i" (CPACF_KM)
>> : "cc", "memory", "0", "1");
>>
>> + kmsan_unpoison_memory(dest, src_len - s.odd);
>> return src_len - s.odd;
>> }
>>
>> @@ -454,6 +457,7 @@ static inline int cpacf_kmc(unsigned long func,
>> void *param,
>> [opc] "i" (CPACF_KMC)
>> : "cc", "memory", "0", "1");
>>
>> + kmsan_unpoison_memory(dest, src_len - s.odd);
>> return src_len - s.odd;
>> }
>>
>> @@ -587,6 +591,7 @@ static inline int cpacf_kmctr(unsigned long func,
>> void *param, u8 *dest,
>> [opc] "i" (CPACF_KMCTR)
>> : "cc", "memory", "0", "1");
>>
>> + kmsan_unpoison_memory(dest, src_len - s.odd);
>> return src_len - s.odd;
>> }
>>
>> @@ -619,6 +624,7 @@ static inline void cpacf_prno(unsigned long func,
>> void *param,
>> : [fc] "d" (func), [pba] "d" ((unsigned long)param),
>> [seed] "d" (s.pair), [opc] "i" (CPACF_PRNO)
>> : "cc", "memory", "0", "1");
>> + kmsan_unpoison_memory(dest, dest_len);
>> }
>>
>> /**
>> @@ -731,6 +737,7 @@ static inline void cpacf_kma(unsigned long func,
>> void *param, u8 *dest,
>> : [fc] "d" (func), [pba] "d" ((unsigned long)param),
>> [opc] "i" (CPACF_KMA)
>> : "cc", "memory", "0", "1");
>> + kmsan_unpoison_memory(dest, src_len);
>
> I am unhappy with this kma thing. This would only work properly with
> CC 0. But CC 1 and 2 are not handled properly. However, I had a closer
> look onto the AR for kma and ... well this inline function should
> handle CC 1 and CC 2 somehow and it should similar to the other inline
> functions return the number of bytes processed like for example cpacf_km().
> I'll open up a bugzilla to fix this kma inline function.
> If you leave out this kma hunk you can add my R-b.
Will do, thanks!
May I ask you to add a proper KMSAN annotation while fixing CC1/CC2
cases? Alternatively I can do it myself afterwards, of course.
>
>> }
>>
>> #endif /* _ASM_S390_CPACF_H */
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] s390/cpacf: Unpoison instruction results
2026-08-13 14:09 ` Ilya Leoshkevich
@ 2026-08-13 15:51 ` Harald Freudenberger
0 siblings, 0 replies; 4+ messages in thread
From: Harald Freudenberger @ 2026-08-13 15:51 UTC (permalink / raw)
To: Ilya Leoshkevich
Cc: Holger Dengler, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
linux-s390, linux-kernel
On 2026-08-13 16:09, Ilya Leoshkevich wrote:
> On 8/13/26 16:06, Harald Freudenberger wrote:
>> On 2026-08-07 14:20, Ilya Leoshkevich wrote:
>>> Stop KMSAN from complaining about CPACF outputs being uninitialized.
>>>
>>> Do not unpoison variable-length parameter blocks: mapping function
>>> codes (like CPACF_KIMD_SHA_256) to lengths is ugly. Let the callers
>>> handle this once need arises.
>>>
>>> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
>>> ---
>>> v1:
>>> https://lore.kernel.org/linux-s390/20260806190223.3292580-1-
>>> iii@linux.ibm.com/
>>> v1 -> v2: Unpoison outputs of more instructions (Sashiko).
>>>
>>
>> See my comment below.
>>
>>> arch/s390/include/asm/cpacf.h | 7 +++++++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git a/arch/s390/include/asm/cpacf.h b/arch/s390/include/asm/
>>> cpacf.h
>>> index a83683169d98d..13d6a6344802a 100644
>>> --- a/arch/s390/include/asm/cpacf.h
>>> +++ b/arch/s390/include/asm/cpacf.h
>>> @@ -301,6 +301,7 @@ static __always_inline void
>>> __cpacf_query(unsigned
>>> int opcode,
>>> cpacf_mask_t *mask)
>>> {
>>> __cpacf_query_insn(opcode, mask, CPACF_FC_QUERY);
>>> + kmsan_unpoison_memory(mask, sizeof(*mask));
>>> }
>>>
>>> static __always_inline int __cpacf_check_opcode(unsigned int opcode)
>>> @@ -370,6 +371,7 @@ static __always_inline int
>>> cpacf_query_func(unsigned int opcode,
>>> static __always_inline void __cpacf_qai(unsigned int opcode,
>>> cpacf_qai_t *qai)
>>> {
>>> __cpacf_query_insn(opcode, qai, CPACF_FC_QUERY_AUTH_INFO);
>>> + kmsan_unpoison_memory(qai, sizeof(*qai));
>>> }
>>>
>>> /**
>>> @@ -422,6 +424,7 @@ static inline int cpacf_km(unsigned long func,
>>> void *param,
>>> [opc] "i" (CPACF_KM)
>>> : "cc", "memory", "0", "1");
>>>
>>> + kmsan_unpoison_memory(dest, src_len - s.odd);
>>> return src_len - s.odd;
>>> }
>>>
>>> @@ -454,6 +457,7 @@ static inline int cpacf_kmc(unsigned long func,
>>> void *param,
>>> [opc] "i" (CPACF_KMC)
>>> : "cc", "memory", "0", "1");
>>>
>>> + kmsan_unpoison_memory(dest, src_len - s.odd);
>>> return src_len - s.odd;
>>> }
>>>
>>> @@ -587,6 +591,7 @@ static inline int cpacf_kmctr(unsigned long func,
>>> void *param, u8 *dest,
>>> [opc] "i" (CPACF_KMCTR)
>>> : "cc", "memory", "0", "1");
>>>
>>> + kmsan_unpoison_memory(dest, src_len - s.odd);
>>> return src_len - s.odd;
>>> }
>>>
>>> @@ -619,6 +624,7 @@ static inline void cpacf_prno(unsigned long func,
>>> void *param,
>>> : [fc] "d" (func), [pba] "d" ((unsigned long)param),
>>> [seed] "d" (s.pair), [opc] "i" (CPACF_PRNO)
>>> : "cc", "memory", "0", "1");
>>> + kmsan_unpoison_memory(dest, dest_len);
>>> }
>>>
>>> /**
>>> @@ -731,6 +737,7 @@ static inline void cpacf_kma(unsigned long func,
>>> void *param, u8 *dest,
>>> : [fc] "d" (func), [pba] "d" ((unsigned long)param),
>>> [opc] "i" (CPACF_KMA)
>>> : "cc", "memory", "0", "1");
>>> + kmsan_unpoison_memory(dest, src_len);
>>
>> I am unhappy with this kma thing. This would only work properly with
>> CC 0. But CC 1 and 2 are not handled properly. However, I had a closer
>> look onto the AR for kma and ... well this inline function should
>> handle CC 1 and CC 2 somehow and it should similar to the other inline
>> functions return the number of bytes processed like for example
>> cpacf_km().
>> I'll open up a bugzilla to fix this kma inline function.
>> If you leave out this kma hunk you can add my R-b.
>
> Will do, thanks!
>
> May I ask you to add a proper KMSAN annotation while fixing CC1/CC2
> cases? Alternatively I can do it myself afterwards, of course.
>
Yes, I'll do that.
>>
>>> }
>>>
>>> #endif /* _ASM_S390_CPACF_H */
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-08-13 15:51 ` Harald Freudenberger
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