Re: [PATCH v5 04/10] drm/amdgpu: create GFX-gen11 usermode queue

[Shashank Sharma <shashank.sharma@xxxxxxx>]

On 07/07/2023 10:37, Christian König wrote:
> Am 07.07.23 um 09:46 schrieb Shashank Sharma:
> > On 07/07/2023 09:24, Christian König wrote:
> > > Am 06.07.23 um 14:35 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)
> > > > V5:
> > > >     - No need to reserve the bo for MQD (Christian).
> > > >     - Some more changes to support IP specific MQD creation.
> > > >
> > > > 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 | 16 ++++
> > > >   drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c        | 73 
> > > > +++++++++++++++++++
> > > >   .../gpu/drm/amd/include/amdgpu_userqueue.h    |  7 ++
> > > >   3 files changed, 96 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c 
> > > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > > > index e37b5da5a0d0..bb774144c372 100644
> > > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
> > > > @@ -134,12 +134,28 @@ 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_gfx(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 V11 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)
> > > >   {
> > > >       mutex_init(&userq_mgr->userq_mutex);
> > > >       idr_init_base(&userq_mgr->userq_idr, 1);
> > > >       userq_mgr->adev = adev;
> > > >   +    amdgpu_userqueue_setup_gfx(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 c4940b6ea1c4..e76e1b86b434 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"
> > > > @@ -6486,3 +6487,75 @@ const struct amdgpu_ip_block_version 
> > > > gfx_v11_0_ip_block =
> > > >       .rev = 0,
> > > >       .funcs = &gfx_v11_0_ip_funcs,
> > > >   };
> > > > +
> > > > +static int gfx_v11_0_userq_mqd_create(struct amdgpu_userq_mgr 
> > > > *uq_mgr,
> > > > +                      struct drm_amdgpu_userq_in *args_in,
> > > > +                      struct amdgpu_usermode_queue *queue)
> > > > +{
> > > > +    struct amdgpu_device *adev = uq_mgr->adev;
> > > > +    struct amdgpu_mqd *mqd_gfx_generic = 
> > > > &adev->mqds[AMDGPU_HW_IP_GFX];
> > > > +    struct drm_amdgpu_userq_mqd_gfx_v11_0 mqd_user;
> > > > +    struct amdgpu_mqd_prop userq_props;
> > > > +    int r;
> > > > +
> > > > +    /* Incoming MQD parameters from userspace to be saved here */
> > > > +    memset(&mqd_user, 0, sizeof(mqd_user));
> > > > +
> > > > +    /* Structure to initialize MQD for userqueue using generic MQD 
> > > > init function */
> > > > +    memset(&userq_props, 0, sizeof(userq_props));
> > > > +
> > > > +    if (args_in->mqd_size != sizeof(struct 
> > > > drm_amdgpu_userq_mqd_gfx_v11_0)) {
> > > > +        DRM_ERROR("MQD size mismatch\n");
> > > > +        return -EINVAL;
> > > > +    }
> > > > +
> > > > +    if (copy_from_user(&mqd_user, u64_to_user_ptr(args_in->mqd), 
> > > > args_in->mqd_size)) {
> > > > +        DRM_ERROR("Failed to get user MQD\n");
> > > > +        return -EFAULT;
> > > > +    }
> > >
> > > Sorry, I've just seen that now. Please don't have a copy_from_user() 
> > > in the backend!
> > >
> > > This is pure front end stuff which we shouldn't do in hw generation 
> > > specific code.
> > This is a bit difficult to achieve, as you know:
> >
> > - the whole reason we moved to ptr/size based approach from 
> > fix-mqd-structure approach is so that we can support multiple MQD 
> > structures using the same UAPI.
> >
> > - which means that in file amdgpu_userqueue.c layer (say front-end) I 
> > do not know what is the right size of MQD, its independent of IP.
> >
> > - the correct size of MQD can only be known in IP specific functions 
> > which are in gfx_v11.c (back end).
> >
> > - I may be able to achieve it by adding a new fptr get_mqd_size() 
> > which can return the right MQD size for me from backend IP function, 
> > and then I can move this copy from user to front-end. Does it sound 
> > like a good idea to you ?
>
> Just use memdup_user() in the frontend. Allocating structures which 
> are copied from userspace on the stack is usually a bad idea as well.
>
> Then pass in the kernel ptr and size as argument here and validate if 
> what userspace gave us is correct.
This can still allow the user to pass invalid size (0 or too big), how 
to prevent that ? I can still add a check for 0 size, but how about a 
very big but invalid size for MQD ?

- Shashank

> Regards,
> Christian.
>
> > - Shashank
> >
> > > Regards,
> > > Christian.
> > >
> > > > +
> > > > +    /* Create BO for actual Userqueue MQD now */
> > > > +    r = amdgpu_bo_create_kernel(adev, mqd_gfx_generic->mqd_size, 
> > > > PAGE_SIZE,
> > > > +                    AMDGPU_GEM_DOMAIN_GTT,
> > > > +                    &queue->mqd.obj,
> > > > +                    &queue->mqd.gpu_addr,
> > > > +                    &queue->mqd.cpu_ptr);
> > > > +    if (r) {
> > > > +        DRM_ERROR("Failed to allocate BO for userqueue (%d)", r);
> > > > +        return -ENOMEM;
> > > > +    }
> > > > +    memset(queue->mqd.cpu_ptr, 0, mqd_gfx_generic->mqd_size);
> > > > +
> > > > +    /* Initialize the MQD BO with user given values */
> > > > +    userq_props.wptr_gpu_addr = mqd_user.wptr_va;
> > > > +    userq_props.rptr_gpu_addr = mqd_user.rptr_va;
> > > > +    userq_props.queue_size = mqd_user.queue_size;
> > > > +    userq_props.hqd_base_gpu_addr = mqd_user.queue_va;
> > > > +    userq_props.mqd_gpu_addr = queue->mqd.gpu_addr;
> > > > +    userq_props.use_doorbell = true;
> > > > +
> > > > +    r = mqd_gfx_generic->init_mqd(adev, (void 
> > > > *)queue->mqd.cpu_ptr, &userq_props);
> > > > +    if (r) {
> > > > +        DRM_ERROR("Failed to initialize MQD for userqueue\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
> > > > +gfx_v11_0_userq_mqd_destroy(struct amdgpu_userq_mgr *uq_mgr, 
> > > > struct amdgpu_usermode_queue *queue)
> > > > +{
> > > > +    struct amdgpu_userq_obj *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_0_userq_mqd_create,
> > > > +    .mqd_destroy = gfx_v11_0_userq_mqd_destroy,
> > > > +};
> > > > diff --git a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h 
> > > > b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > > > index 55ed6512a565..240f92796f00 100644
> > > > --- a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > > > +++ b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
> > > > @@ -29,6 +29,12 @@
> > > >     struct amdgpu_mqd_prop;
> > > >   +struct amdgpu_userq_obj {
> > > > +    void         *cpu_ptr;
> > > > +    uint64_t     gpu_addr;
> > > > +    struct amdgpu_bo *obj;
> > > > +};
> > > > +
> > > >   struct amdgpu_usermode_queue {
> > > >       int            queue_type;
> > > >       uint64_t        doorbell_handle;
> > > > @@ -37,6 +43,7 @@ struct amdgpu_usermode_queue {
> > > >       struct amdgpu_mqd_prop    *userq_prop;
> > > >       struct amdgpu_userq_mgr *userq_mgr;
> > > >       struct amdgpu_vm    *vm;
> > > > +    struct amdgpu_userq_obj mqd;
> > > >   };
> > > >     struct amdgpu_userq_funcs {