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

["Christian König" <christian.koenig@amd.com>]

Am 07.07.23 um 12:02 schrieb Shashank Sharma:
>
> 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@amd.com>
>>>>> Cc: Christian Koenig <christian.koenig@amd.com>
>>>>> Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
>>>>> Signed-off-by: Arvind Yadav <arvind.yadav@amd.com>
>>>>> ---
>>>>>   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 ?

memdup_user() already takes care of that (has a maximum of 2MiB IIRC) 
and the hw specific function should still validate the size to filter 
out 0 and other invalid values.

Christian.

>
> - 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 {
>>>>
>>