Re: [PATCH v5 03/18] hw/arm/smmuv3: Fix encoding of CLASS in events

[Eric Auger]

Hi Jean,

On 7/15/24 10:45, Mostafa Saleh wrote:
> The SMMUv3 spec (ARM IHI 0070 F.b - 7.3 Event records) defines the
> class of events faults as:
>
> CLASS: The class of the operation that caused the fault:
> - 0b00: CD, CD fetch.
> - 0b01: TTD, Stage 1 translation table fetch.
> - 0b10: IN, Input address
>
> However, this value was not set and left as 0 which means CD and not
> IN (0b10).
>
> Another problem was that stage-2 class is considered IN not TT for
> EABT, according to the spec:
>     Translation of an IPA after successful stage 1 translation (or,
>     in stage 2-only configuration, an input IPA)
>     - S2 == 1 (stage 2), CLASS == IN (Input to stage)
>
> This would change soon when nested translations are supported.
>
> While at it, add an enum for class as it would be used for nesting.
> However, at the moment stage-1 and stage-2 use the same class values,
> except for EABT.
>
> Fixes: 9bde7f0674 “hw/arm/smmuv3: Implement translate callback”
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
> ---
>  hw/arm/smmuv3-internal.h | 6 ++++++
>  hw/arm/smmuv3.c          | 8 +++++++-
>  2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/smmuv3-internal.h b/hw/arm/smmuv3-internal.h
> index e4dd11e1e6..0f3ecec804 100644
> --- a/hw/arm/smmuv3-internal.h
> +++ b/hw/arm/smmuv3-internal.h
> @@ -32,6 +32,12 @@ typedef enum SMMUTranslationStatus {
>      SMMU_TRANS_SUCCESS,
>  } SMMUTranslationStatus;
>  
> +typedef enum SMMUTranslationClass {
> +    SMMU_CLASS_CD,
> +    SMMU_CLASS_TT,
> +    SMMU_CLASS_IN,
> +} SMMUTranslationClass;
> +
>  /* MMIO Registers */
>  
>  REG32(IDR0,                0x0)
> diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
> index 9dd3ea48e4..3d214c9f57 100644
> --- a/hw/arm/smmuv3.c
> +++ b/hw/arm/smmuv3.c
> @@ -942,7 +942,9 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion 
> *mr, hwaddr addr,
>              event.type = SMMU_EVT_F_WALK_EABT;
>              event.u.f_walk_eabt.addr = addr;
>              event.u.f_walk_eabt.rnw = flag & 0x1;
> -            event.u.f_walk_eabt.class = 0x1;
> +            /* Stage-2 (only) is class IN while stage-1 is class TT */
> +            event.u.f_walk_eabt.class = (ptw_info.stage == 2) ?
> +                                         SMMU_CLASS_IN : SMMU_CLASS_TT;
does it match your expectations. While reading your previous comment I
have the impression what you had in mind was more complicated than that

* s2 walk that encounters EABT on S2 descriptor while translating
  non-descriptor IPA is reported as class=IN, even when doing s2-only.

Thanks

Eric

>              event.u.f_walk_eabt.addr2 = ptw_info.addr;
>              break;
>          case SMMU_PTW_ERR_TRANSLATION:
> @@ -950,6 +952,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion 
> *mr, hwaddr addr,
>                  event.type = SMMU_EVT_F_TRANSLATION;
>                  event.u.f_translation.addr = addr;
>                  event.u.f_translation.addr2 = ptw_info.addr;
> +                event.u.f_translation.class = SMMU_CLASS_IN;
>                  event.u.f_translation.rnw = flag & 0x1;
>              }
>              break;
> @@ -958,6 +961,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion 
> *mr, hwaddr addr,
>                  event.type = SMMU_EVT_F_ADDR_SIZE;
>                  event.u.f_addr_size.addr = addr;
>                  event.u.f_addr_size.addr2 = ptw_info.addr;
> +                event.u.f_translation.class = SMMU_CLASS_IN;
>                  event.u.f_addr_size.rnw = flag & 0x1;
>              }
>              break;
> @@ -966,6 +970,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion 
> *mr, hwaddr addr,
>                  event.type = SMMU_EVT_F_ACCESS;
>                  event.u.f_access.addr = addr;
>                  event.u.f_access.addr2 = ptw_info.addr;
> +                event.u.f_translation.class = SMMU_CLASS_IN;
>                  event.u.f_access.rnw = flag & 0x1;
>              }
>              break;
> @@ -974,6 +979,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion 
> *mr, hwaddr addr,
>                  event.type = SMMU_EVT_F_PERMISSION;
>                  event.u.f_permission.addr = addr;
>                  event.u.f_permission.addr2 = ptw_info.addr;
> +                event.u.f_translation.class = SMMU_CLASS_IN;
>                  event.u.f_permission.rnw = flag & 0x1;
>              }
>              break;