[PATCH drm-misc-next v2] drm/nouveau: uapi: don't pass NO_PREFETCH flag implicitly

Faith Ekstrand faith at gfxstrand.net
Wed Aug 23 20:39:13 UTC 2023


On Wed, Aug 23, 2023 at 1:17 PM Danilo Krummrich <dakr at redhat.com> wrote:

> Currently, NO_PREFETCH is passed implicitly through
> drm_nouveau_gem_pushbuf_push::length and drm_nouveau_exec_push::va_len.
>
> Since this is a direct representation of how the HW is programmed it
> isn't really future proof for a uAPI. Hence, fix this up for the new
> uAPI and split up the va_len field of struct drm_nouveau_exec_push,
> such that we keep 32bit for va_len and 32bit for flags.
>
> For drm_nouveau_gem_pushbuf_push::length at least provide
> NOUVEAU_GEM_PUSHBUF_NO_PREFETCH to indicate the bit shift.
>
> While at it, fix up nv50_dma_push() as well, such that the caller
> doesn't need to encode the NO_PREFETCH flag into the length parameter.
>
> Signed-off-by: Danilo Krummrich <dakr at redhat.com>
>

Still

Reviewed-by: Faith Ekstrand <faith.ekstrand at collabora.com>


> ---
> Changes in v2:
>   - dma: rename prefetch to no_prefetch in nv50_dma_push() (Faith)
>   - exec: print error message when pushbuf size larger max pushbuf size
> (Faith)
> ---
>  drivers/gpu/drm/nouveau/nouveau_dma.c  |  7 +++++--
>  drivers/gpu/drm/nouveau/nouveau_dma.h  |  8 ++++++--
>  drivers/gpu/drm/nouveau/nouveau_exec.c | 19 ++++++++++++++++---
>  drivers/gpu/drm/nouveau/nouveau_gem.c  |  6 ++++--
>  include/uapi/drm/nouveau_drm.h         |  8 +++++++-
>  5 files changed, 38 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_dma.c
> b/drivers/gpu/drm/nouveau/nouveau_dma.c
> index b90cac6d5772..b01c029f3a90 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_dma.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_dma.c
> @@ -69,16 +69,19 @@ READ_GET(struct nouveau_channel *chan, uint64_t
> *prev_get, int *timeout)
>  }
>
>  void
> -nv50_dma_push(struct nouveau_channel *chan, u64 offset, int length)
> +nv50_dma_push(struct nouveau_channel *chan, u64 offset, u32 length,
> +             bool no_prefetch)
>  {
>         struct nvif_user *user = &chan->drm->client.device.user;
>         struct nouveau_bo *pb = chan->push.buffer;
>         int ip = (chan->dma.ib_put * 2) + chan->dma.ib_base;
>
>         BUG_ON(chan->dma.ib_free < 1);
> +       WARN_ON(length > NV50_DMA_PUSH_MAX_LENGTH);
>
>         nouveau_bo_wr32(pb, ip++, lower_32_bits(offset));
> -       nouveau_bo_wr32(pb, ip++, upper_32_bits(offset) | length << 8);
> +       nouveau_bo_wr32(pb, ip++, upper_32_bits(offset) | length << 8 |
> +                       (no_prefetch ? (1 << 31) : 0));
>
>         chan->dma.ib_put = (chan->dma.ib_put + 1) & chan->dma.ib_max;
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_dma.h
> b/drivers/gpu/drm/nouveau/nouveau_dma.h
> index 035a709c7be1..1744d95b233e 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_dma.h
> +++ b/drivers/gpu/drm/nouveau/nouveau_dma.h
> @@ -31,7 +31,8 @@
>  #include "nouveau_chan.h"
>
>  int nouveau_dma_wait(struct nouveau_channel *, int slots, int size);
> -void nv50_dma_push(struct nouveau_channel *, u64 addr, int length);
> +void nv50_dma_push(struct nouveau_channel *, u64 addr, u32 length,
> +                  bool no_prefetch);
>
>  /*
>   * There's a hw race condition where you can't jump to your PUT offset,
> @@ -45,6 +46,9 @@ void nv50_dma_push(struct nouveau_channel *, u64 addr,
> int length);
>   */
>  #define NOUVEAU_DMA_SKIPS (128 / 4)
>
> +/* Maximum push buffer size. */
> +#define NV50_DMA_PUSH_MAX_LENGTH 0x7fffff
> +
>  /* Object handles - for stuff that's doesn't use handle == oclass. */
>  enum {
>         NvDmaFB         = 0x80000002,
> @@ -89,7 +93,7 @@ FIRE_RING(struct nouveau_channel *chan)
>
>         if (chan->dma.ib_max) {
>                 nv50_dma_push(chan, chan->push.addr + (chan->dma.put << 2),
> -                             (chan->dma.cur - chan->dma.put) << 2);
> +                             (chan->dma.cur - chan->dma.put) << 2, false);
>         } else {
>                 WRITE_PUT(chan->dma.cur);
>         }
> diff --git a/drivers/gpu/drm/nouveau/nouveau_exec.c
> b/drivers/gpu/drm/nouveau/nouveau_exec.c
> index 0f927adda4ed..a90c4cd8cbb2 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_exec.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_exec.c
> @@ -164,8 +164,10 @@ nouveau_exec_job_run(struct nouveau_job *job)
>         }
>
>         for (i = 0; i < exec_job->push.count; i++) {
> -               nv50_dma_push(chan, exec_job->push.s[i].va,
> -                             exec_job->push.s[i].va_len);
> +               struct drm_nouveau_exec_push *p = &exec_job->push.s[i];
> +               bool no_prefetch = p->flags &
> DRM_NOUVEAU_EXEC_PUSH_NO_PREFETCH;
> +
> +               nv50_dma_push(chan, p->va, p->va_len, no_prefetch);
>         }
>
>         ret = nouveau_fence_emit(fence, chan);
> @@ -223,7 +225,18 @@ nouveau_exec_job_init(struct nouveau_exec_job **pjob,
>  {
>         struct nouveau_exec_job *job;
>         struct nouveau_job_args args = {};
> -       int ret;
> +       int i, ret;
> +
> +       for (i = 0; i < __args->push.count; i++) {
> +               struct drm_nouveau_exec_push *p = &__args->push.s[i];
> +
> +               if (unlikely(p->va_len > NV50_DMA_PUSH_MAX_LENGTH)) {
> +                       NV_PRINTK(err, nouveau_cli(__args->file_priv),
> +                                 "pushbuf size exceeds limit: 0x%x max
> 0x%x\n",
> +                                 p->va_len, NV50_DMA_PUSH_MAX_LENGTH);
> +                       return -EINVAL;
> +               }
> +       }
>
>         job = *pjob = kzalloc(sizeof(*job), GFP_KERNEL);
>         if (!job)
> diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c
> b/drivers/gpu/drm/nouveau/nouveau_gem.c
> index f39360870c70..c0b10d8d3d03 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_gem.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
> @@ -856,9 +856,11 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev,
> void *data,
>                 for (i = 0; i < req->nr_push; i++) {
>                         struct nouveau_vma *vma = (void *)(unsigned long)
>                                 bo[push[i].bo_index].user_priv;
> +                       u64 addr = vma->addr + push[i].offset;
> +                       u32 length = push[i].length &
> ~NOUVEAU_GEM_PUSHBUF_NO_PREFETCH;
> +                       bool no_prefetch = push[i].length &
> NOUVEAU_GEM_PUSHBUF_NO_PREFETCH;
>
> -                       nv50_dma_push(chan, vma->addr + push[i].offset,
> -                                     push[i].length);
> +                       nv50_dma_push(chan, addr, length, no_prefetch);
>                 }
>         } else
>         if (drm->client.device.info.chipset >= 0x25) {
> diff --git a/include/uapi/drm/nouveau_drm.h
> b/include/uapi/drm/nouveau_drm.h
> index b1ad9d5ffce8..8f16724b5d05 100644
> --- a/include/uapi/drm/nouveau_drm.h
> +++ b/include/uapi/drm/nouveau_drm.h
> @@ -138,6 +138,7 @@ struct drm_nouveau_gem_pushbuf_push {
>         __u32 pad;
>         __u64 offset;
>         __u64 length;
> +#define NOUVEAU_GEM_PUSHBUF_NO_PREFETCH (1 << 23)
>  };
>
>  struct drm_nouveau_gem_pushbuf {
> @@ -338,7 +339,12 @@ struct drm_nouveau_exec_push {
>         /**
>          * @va_len: the length of the push buffer mapping
>          */
> -       __u64 va_len;
> +       __u32 va_len;
> +       /**
> +        * flags: the flags for this push buffer mapping
> +        */
> +       __u32 flags;
> +#define DRM_NOUVEAU_EXEC_PUSH_NO_PREFETCH 0x1
>  };
>
>  /**
>
> base-commit: b4e9fa933551e51459c634dc4396171dc65284a6
> --
> 2.41.0
>
>
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