[PATCH] drm/amd: SVM flag error added at svm_range flags

[Felix Kuehling]

This flag was never meant for user mode. Alex ended up implementing it 
differently in a way that doesn't need to change the flags exposed to 
user mode. See his patch "drm/amdkfd: flag added to handle errors from 
svm validate and map". This patch is no longer needed.


Regards,
   Felix


Am 2023-05-31 um 10:09 schrieb Deucher, Alexander:
>
> [Public]
>
>
> Where is the userspace code which uses this new interface? Can you add 
> a link to the relevant branch to the commit message?
>
> Alex
> ------------------------------------------------------------------------
> *From:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of 
> Alex Sierra <alex.sierra at amd.com>
> *Sent:* Monday, May 29, 2023 4:09 PM
> *To:* amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; 
> Kuehling, Felix <Felix.Kuehling at amd.com>
> *Cc:* Sierra Guiza, Alejandro (Alex) <Alex.Sierra at amd.com>; Yang, 
> Philip <Philip.Yang at amd.com>
> *Subject:* [PATCH] drm/amd: SVM flag error added at svm_range flags
> If a return error is raised during validation and mapping of a
> prange, this flag is set. It is a rare occurrence, but it could happen
> when `amdgpu_hmm_range_get_pages_done` returns true. In such cases,
> the caller should retry. However, it is important to ensure that the
> prange is updated correctly during the retry.
>
> Signed-off-by: Alex Sierra <alex.sierra at amd.com>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 12 +++++++++++-
>  include/uapi/linux/kfd_ioctl.h       |  2 ++
>  2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
> b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index fcfde9140bce..96abae515bcf 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -756,10 +756,12 @@ svm_range_apply_attrs(struct kfd_process *p, 
> struct svm_range *prange,
>                          break;
>                  case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
>                          *update_mapping = true;
> +                       attrs[i].value &= ~KFD_IOCTL_SVM_FLAG_ERROR;
>                          prange->flags |= attrs[i].value;
>                          break;
>                  case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
>                          *update_mapping = true;
> +                       attrs[i].value &= ~KFD_IOCTL_SVM_FLAG_ERROR;
>                          prange->flags &= ~attrs[i].value;
>                          break;
>                  case KFD_IOCTL_SVM_ATTR_GRANULARITY:
> @@ -778,6 +780,9 @@ svm_range_is_same_attrs(struct kfd_process *p, 
> struct svm_range *prange,
>          uint32_t i;
>          int gpuidx;
>
> +       if (prange->flags & KFD_IOCTL_SVM_FLAG_ERROR)
> +               return false;
> +
>          for (i = 0; i < nattr; i++) {
>                  switch (attrs[i].type) {
>                  case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
> @@ -1657,8 +1662,11 @@ static int svm_range_validate_and_map(struct 
> mm_struct *mm,
>  unreserve_out:
>          svm_range_unreserve_bos(&ctx);
>
> -       if (!r)
> +       prange->flags |= KFD_IOCTL_SVM_FLAG_ERROR;
> +       if (!r) {
> +               prange->flags &= ~KFD_IOCTL_SVM_FLAG_ERROR;
>                  prange->validate_timestamp = ktime_get_boottime();
> +       }
>
>          return r;
>  }
> @@ -3674,9 +3682,11 @@ svm_range_get_attr(struct kfd_process *p, 
> struct mm_struct *mm,
>                          break;
>                  case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
>                          attrs[i].value = flags_and;
> +                       attrs[i].value &= ~KFD_IOCTL_SVM_FLAG_ERROR;
>                          break;
>                  case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
>                          attrs[i].value = ~flags_or;
> +                       attrs[i].value &= ~KFD_IOCTL_SVM_FLAG_ERROR;
>                          break;
>                  case KFD_IOCTL_SVM_ATTR_GRANULARITY:
>                          attrs[i].value = (uint32_t)granularity;
> diff --git a/include/uapi/linux/kfd_ioctl.h 
> b/include/uapi/linux/kfd_ioctl.h
> index 7e19a2d1e907..2b6f68bd06da 100644
> --- a/include/uapi/linux/kfd_ioctl.h
> +++ b/include/uapi/linux/kfd_ioctl.h
> @@ -1125,6 +1125,8 @@ struct kfd_ioctl_cross_memory_copy_deprecated_args {
>  #define KFD_IOCTL_SVM_FLAG_GPU_READ_MOSTLY 0x00000020
>  /* Keep GPU memory mapping always valid as if XNACK is disable */
>  #define KFD_IOCTL_SVM_FLAG_GPU_ALWAYS_MAPPED 0x00000040
> +/* Set during svm validation and map error */
> +#define KFD_IOCTL_SVM_FLAG_ERROR       0x80000000
>
>  /**
>   * kfd_ioctl_svm_op - SVM ioctl operations
> -- 
> 2.32.0
>