Re: [PATCH v4 04/10] drm/amdgpu: create GFX-gen11 MQD for userqueue

[Christian König <christian.koenig@xxxxxxx>]

Am 25.04.23 um 15:10 schrieb Shashank Sharma:
> On 25/04/2023 14:27, Christian König wrote:
> > Am 24.04.23 um 19:38 schrieb Shashank Sharma:
> > > A Memory queue descriptor (MQD) of a userqueue defines it in
> > > the hw's context. As MQD format can vary between different
> > > graphics IPs, we need gfx GEN specific handlers to create MQDs.
> > >
> > > This patch:
> > > - Introduces MQD handler functions for the usermode queues.
> > > - Adds new functions to create and destroy userqueue MQD for
> > >    GFX-GEN-11 IP
> > >
> > > V1: Worked on review comments from Alex:
> > >      - Make MQD functions GEN and IP specific
> > >
> > > V2: Worked on review comments from Alex:
> > >      - Reuse the existing adev->mqd[ip] for MQD creation
> > >      - Formatting and arrangement of code
> > >
> > > V3:
> > >      - Integration with doorbell manager
> > >
> > > V4: Review comments addressed:
> > >      - Do not create a new file for userq, reuse gfx_v11_0.c (Alex)
> > >      - Align name of structure members (Luben)
> > >      - Don't break up the Cc tag list and the Sob tag list in commit
> > >        message (Luben)
> > >
> > > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > > Cc: Christian Koenig <christian.koenig@xxxxxxx>
> > > Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxx>
> > > Signed-off-by: Arvind Yadav <arvind.yadav@xxxxxxx>
> > > ---
> > >   drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c | 25 ++++++++
> > >   drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c        | 57 
> > > +++++++++++++++++++
> > >   .../gpu/drm/amd/include/amdgpu_userqueue.h    |  7 +++
> > >   3 files changed, 89 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c 
> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > > index 333f31efbe7b..e95fb35b0cb5 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > > @@ -81,6 +81,14 @@ static int amdgpu_userqueue_create_gfx(struct 
> > > drm_file *filp, union drm_amdgpu_u
> > >           goto free_queue;
> > >       }
> > >   +    if (uq_mgr->userq_funcs[queue->queue_type]->mqd_create) {
> > > +        r = 
> > > uq_mgr->userq_funcs[queue->queue_type]->mqd_create(uq_mgr, queue);
> > > +        if (r) {
> > > +            DRM_ERROR("Failed to create/map userqueue MQD\n");
> > > +            goto free_queue;
> > > +        }
> > > +    }
> > > +
> > >       args->out.queue_id = queue->queue_id;
> > >       args->out.flags = 0;
> > >       mutex_unlock(&uq_mgr->userq_mutex);
> > > @@ -119,6 +127,8 @@ static void amdgpu_userqueue_destroy(struct 
> > > drm_file *filp, int queue_id)
> > >       }
> > >         mutex_lock(&uq_mgr->userq_mutex);
> > > +    if (uq_mgr->userq_funcs[queue->queue_type]->mqd_destroy)
> > > + uq_mgr->userq_funcs[queue->queue_type]->mqd_destroy(uq_mgr, queue);
> > >       amdgpu_userqueue_free_index(uq_mgr, queue->queue_id);
> > >       mutex_unlock(&uq_mgr->userq_mutex);
> > >       kfree(queue);
> > > @@ -149,6 +159,20 @@ int amdgpu_userq_ioctl(struct drm_device *dev, 
> > > void *data,
> > >       return r;
> > >   }
> > >   +extern const struct amdgpu_userq_funcs userq_gfx_v11_funcs;
> > > +
> > > +static void
> > > +amdgpu_userqueue_setup_ip_funcs(struct amdgpu_userq_mgr *uq_mgr)
> > > +{
> > > +    int maj;
> > > +    struct amdgpu_device *adev = uq_mgr->adev;
> > > +    uint32_t version = adev->ip_versions[GC_HWIP][0];
> > > +
> > > +    /* We support usermode queue only for GFX IP as of now */
> > > +    maj = IP_VERSION_MAJ(version);
> > > +    if (maj == 11)
> > > +        uq_mgr->userq_funcs[AMDGPU_HW_IP_GFX] = &userq_gfx_v11_funcs;
> > > +}
> > >     int amdgpu_userq_mgr_init(struct amdgpu_userq_mgr *userq_mgr, 
> > > struct amdgpu_device *adev)
> > >   {
> > > @@ -156,6 +180,7 @@ int amdgpu_userq_mgr_init(struct 
> > > amdgpu_userq_mgr *userq_mgr, struct amdgpu_devi
> > >       idr_init_base(&userq_mgr->userq_idr, 1);
> > >       userq_mgr->adev = adev;
> > >   +    amdgpu_userqueue_setup_ip_funcs(userq_mgr);
> > >       return 0;
> > >   }
> > >   diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c 
> > > b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> > > index a56c6e106d00..9f7b14966ac8 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> > > @@ -30,6 +30,7 @@
> > >   #include "amdgpu_psp.h"
> > >   #include "amdgpu_smu.h"
> > >   #include "amdgpu_atomfirmware.h"
> > > +#include "amdgpu_userqueue.h"
> > >   #include "imu_v11_0.h"
> > >   #include "soc21.h"
> > >   #include "nvd.h"
> > > @@ -6404,3 +6405,59 @@ const struct amdgpu_ip_block_version 
> > > gfx_v11_0_ip_block =
> > >       .rev = 0,
> > >       .funcs = &gfx_v11_0_ip_funcs,
> > >   };
> > > +
> > > +static int
> > > +gfx_v11_userq_mqd_create(struct amdgpu_userq_mgr *uq_mgr, struct 
> > > amdgpu_usermode_queue *queue)
> > > +{
> > > +    struct amdgpu_device *adev = uq_mgr->adev;
> > > +    struct amdgpu_userq_ctx_space *mqd = &queue->mqd;
> > > +    struct amdgpu_mqd *gfx_v11_mqd = &adev->mqds[queue->queue_type];
> > > +    int size = gfx_v11_mqd->mqd_size;
> > > +    int r;
> > > +
> > > +    r = amdgpu_bo_create_kernel(adev, size, PAGE_SIZE,
> > > +                    AMDGPU_GEM_DOMAIN_GTT,
> > > +                    &mqd->obj,
> > > +                    &mqd->gpu_addr,
> > > +                    &mqd->cpu_ptr);
> > > +    if (r) {
> > > +        DRM_ERROR("Failed to allocate bo for userqueue (%d)", r);
> > > +        return r;
> > > +    }
> > > +
> > > +    memset(mqd->cpu_ptr, 0, size);
> > > +    r = amdgpu_bo_reserve(mqd->obj, false);
> > > +    if (unlikely(r != 0)) {
> > > +        DRM_ERROR("Failed to reserve mqd for userqueue (%d)", r);
> > > +        goto free_mqd;
> > > +    }
> >
> > This reserve/unreserve dance here doesn't seem to make much sense. 
> > Why do you do that?
> We wanted to make sure that the MQD buffer is reserved until we fill 
> it. Does it sound incorrect ?

Yeah, that sounds strongly like we have some misunderstanding.

Reserving a buffer is needed for two thing:
1. Prevent that it moves around.
2. Change some parameters of the BO.

Since the BO is a pinned kernel BO neither of those two use cases seems 
to be the case here.

So why do you reserve the BO here?

> > Christian.
> >
> > > +
> > > +    queue->userq_prop.use_doorbell = true;
> > > +    queue->userq_prop.mqd_gpu_addr = mqd->gpu_addr;
> >
> > Are those the only two parameters needed? If yes we should probably 
> > drop the userq_prop structure and give them directly.
> In patch set 1 and 2, everything was getting stored directly in the 
> queue, but then we decided to re-use the existing init_mqd() functions 
> from each of the IP engines.
>
> If you see the prototype of mqd->init_mqd(), it expects userq_prop 
> structure as input parameters, so we encapsulated a subset of queue to 
> this structure.

Yeah, the question is if the init_mqd() interface is a good idea or if 
we should re-work that as well?

Christian.

> - Shashank
>
> > Christian.
> >
> > > +    r = gfx_v11_mqd->init_mqd(adev, (void *)mqd->cpu_ptr, 
> > > &queue->userq_prop);
> > > +    amdgpu_bo_unreserve(mqd->obj);
> > > +    if (r) {
> > > +        DRM_ERROR("Failed to init MQD for queue\n");
> > > +        goto free_mqd;
> > > +    }
> > > +
> > > +    DRM_DEBUG_DRIVER("MQD for queue %d created\n", queue->queue_id);
> > > +    return 0;
> > > +
> > > +free_mqd:
> > > +    amdgpu_bo_free_kernel(&mqd->obj, &mqd->gpu_addr, &mqd->cpu_ptr);
> > > +    return r;
> > > +}
> > > +
> > > +static void
> > > +gfx_v11_userq_mqd_destroy(struct amdgpu_userq_mgr *uq_mgr, struct 
> > > amdgpu_usermode_queue *queue)
> > > +{
> > > +    struct amdgpu_userq_ctx_space *mqd = &queue->mqd;
> > > +
> > > +    amdgpu_bo_free_kernel(&mqd->obj, &mqd->gpu_addr, &mqd->cpu_ptr);
> > > +}
> > > +
> > > +const struct amdgpu_userq_funcs userq_gfx_v11_funcs = {
> > > +    .mqd_create = gfx_v11_userq_mqd_create,
> > > +    .mqd_destroy = gfx_v11_userq_mqd_destroy,
> > > +};
> > > diff --git a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h 
> > > b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > > index 8d8f6b3bcda5..e7da27918bd2 100644
> > > --- a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > > +++ b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > > @@ -28,6 +28,12 @@
> > >   #include "amdgpu.h"
> > >   #define AMDGPU_MAX_USERQ 512
> > >   +struct amdgpu_userq_ctx_space {
> > > +    uint64_t     gpu_addr;
> > > +    void         *cpu_ptr;
> > > +    struct amdgpu_bo *obj;
> > > +};
> > > +
> > >   struct amdgpu_usermode_queue {
> > >       int            queue_id;
> > >       int            queue_type;
> > > @@ -36,6 +42,7 @@ struct amdgpu_usermode_queue {
> > >       struct amdgpu_mqd_prop    userq_prop;
> > >       struct amdgpu_userq_mgr *userq_mgr;
> > >       struct amdgpu_vm    *vm;
> > > +    struct amdgpu_userq_ctx_space mqd;
> > >   };
> > >     struct amdgpu_userq_funcs {