Re: [PATCH 3/8] drm/amdgpu: introduce userqueue MQD handlers

[Shashank Sharma <shashank.sharma@xxxxxxx>]

On 07/02/2023 08:11, Christian König wrote:
> Am 03.02.23 um 22:54 schrieb Shashank Sharma:
> > From: Shashank Sharma <contactshashanksharma@xxxxxxxxx>
> >
> > A Memory queue descriptor (MQD) of a userqueue defines it in the 
> > harware's
> > context. As the method of formation of a MQD, and its format can vary 
> > between
> > different graphics IPs, we need gfx GEN specific handlers to create 
> > MQDs.
> >
> > This patch:
> > - Introduces MQD hander functions for the usermode queues
> > - A general function to create and destroy MQD for a userqueue.
> >
> > V1: Worked on review comments from Alex on RFC patches:
> >      MQD creation should be gen and IP specific.
> >
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > Cc: Christian Koenig <christian.koenig@xxxxxxx>
> > Signed-off-by: Shashank Sharma <contactshashanksharma@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c | 64 +++++++++++++++++++
> >   .../gpu/drm/amd/include/amdgpu_userqueue.h    |  9 +++
> >   2 files changed, 73 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > index d5bc7fe81750..625c2fe1e84a 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > @@ -42,6 +42,60 @@ static struct amdgpu_usermode_queue
> >       return idr_find(&uq_mgr->userq_idr, qid);
> >   }
> >   +static int
> > +amdgpu_userqueue_create_mqd(struct amdgpu_userq_mgr *uq_mgr, struct 
> > amdgpu_usermode_queue *queue)
> > +{
> > +    int r;
> > +    int size;
> > +    struct amdgpu_device *adev = uq_mgr->adev;
> > +
> > +    if (!uq_mgr->userq_mqd_funcs) {
> > +        DRM_ERROR("Userqueue not initialized\n");
> > +        return -EINVAL;
> > +    }
> > +
> > +    size = uq_mgr->userq_mqd_funcs->mqd_size(uq_mgr);
> > +    r = amdgpu_bo_create_kernel(adev, size, PAGE_SIZE,
> > +                                AMDGPU_GEM_DOMAIN_VRAM,
> > +                                &queue->mqd_obj,
> > +                                &queue->mqd_gpu_addr,
> > +                                &queue->mqd_cpu_ptr);
>
> We can't use amdgpu_bo_create_kernel() here, this pins the BO.
>
> Instead all BOs of the process must be fenced with some eviction fence.


Noted,

- Shashank

> Christian.
>
> > +    if (r) {
> > +        DRM_ERROR("Failed to allocate bo for userqueue (%d)", r);
> > +        return r;
> > +    }
> > +
> > +    memset(queue->mqd_cpu_ptr, 0, size);
> > +    r = amdgpu_bo_reserve(queue->mqd_obj, false);
> > +    if (unlikely(r != 0)) {
> > +        DRM_ERROR("Failed to reserve mqd for userqueue (%d)", r);
> > +        goto free_mqd;
> > +    }
> > +
> > +    r = uq_mgr->userq_mqd_funcs->mqd_create(uq_mgr, queue);
> > +    amdgpu_bo_unreserve(queue->mqd_obj);
> > +    if (r) {
> > +        DRM_ERROR("Failed to create MQD for queue\n");
> > +        goto free_mqd;
> > +    }
> > +    return 0;
> > +
> > +free_mqd:
> > +    amdgpu_bo_free_kernel(&queue->mqd_obj,
> > +               &queue->mqd_gpu_addr,
> > +               &queue->mqd_cpu_ptr);
> > +   return r;
> > +}
> > +
> > +static void
> > +amdgpu_userqueue_destroy_mqd(struct amdgpu_userq_mgr *uq_mgr, struct 
> > amdgpu_usermode_queue *queue)
> > +{
> > +    uq_mgr->userq_mqd_funcs->mqd_destroy(uq_mgr, queue);
> > +    amdgpu_bo_free_kernel(&queue->mqd_obj,
> > +               &queue->mqd_gpu_addr,
> > +               &queue->mqd_cpu_ptr);
> > +}
> > +
> >   static int amdgpu_userqueue_create(struct drm_file *filp, union 
> > drm_amdgpu_userq *args)
> >   {
> >       int r, pasid;
> > @@ -82,12 +136,21 @@ static int amdgpu_userqueue_create(struct 
> > drm_file *filp, union drm_amdgpu_userq
> >           goto free_queue;
> >       }
> >   +    r = amdgpu_userqueue_create_mqd(uq_mgr, queue);
> > +    if (r) {
> > +        DRM_ERROR("Failed to create MQD\n");
> > +        goto free_qid;
> > +    }
> > +
> >       list_add_tail(&queue->userq_node, &uq_mgr->userq_list);
> >       args->out.q_id = queue->queue_id;
> >       args->out.flags = 0;
> >       mutex_unlock(&uq_mgr->userq_mutex);
> >       return 0;
> >   +free_qid:
> > +    amdgpu_userqueue_free_index(uq_mgr, queue->queue_id);
> > +
> >   free_queue:
> >       mutex_unlock(&uq_mgr->userq_mutex);
> >       kfree(queue);
> > @@ -107,6 +170,7 @@ static void amdgpu_userqueue_destroy(struct 
> > drm_file *filp, int queue_id)
> >       }
> >         mutex_lock(&uq_mgr->userq_mutex);
> > +    amdgpu_userqueue_destroy_mqd(uq_mgr, queue);
> >       amdgpu_userqueue_free_index(uq_mgr, queue->queue_id);
> >       list_del(&queue->userq_node);
> >       mutex_unlock(&uq_mgr->userq_mutex);
> > diff --git a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h 
> > b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > index 9557588fe34f..a6abdfd5cb74 100644
> > --- a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > +++ b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > @@ -26,10 +26,13 @@
> >     #define AMDGPU_MAX_USERQ 512
> >   +struct amdgpu_userq_mqd_funcs;
> > +
> >   struct amdgpu_userq_mgr {
> >       struct idr userq_idr;
> >       struct mutex userq_mutex;
> >       struct list_head userq_list;
> > +    const struct amdgpu_userq_mqd_funcs *userq_mqd_funcs;
> >       struct amdgpu_device *adev;
> >   };
> >   @@ -57,6 +60,12 @@ struct amdgpu_usermode_queue {
> >     int amdgpu_userq_ioctl(struct drm_device *dev, void *data, struct 
> > drm_file *filp);
> >   +struct amdgpu_userq_mqd_funcs {
> > +    int (*mqd_size)(struct amdgpu_userq_mgr *);
> > +    int (*mqd_create)(struct amdgpu_userq_mgr *, struct 
> > amdgpu_usermode_queue *);
> > +    void (*mqd_destroy)(struct amdgpu_userq_mgr *, struct 
> > amdgpu_usermode_queue *);
> > +};
> > +
> >   int amdgpu_userq_mgr_init(struct amdgpu_userq_mgr *userq_mgr, 
> > struct amdgpu_device *adev);
> >     void amdgpu_userq_mgr_fini(struct amdgpu_userq_mgr *userq_mgr);