[PATCH 1/1] drm/amdgpu: add helper function for vm pasid

Christian König ckoenig.leichtzumerken at gmail.com
Mon Jun 21 11:13:52 UTC 2021



Am 21.06.21 um 13:07 schrieb Das, Nirmoy:
>
> On 6/21/2021 12:59 PM, Christian König wrote:
>> Am 21.06.21 um 12:56 schrieb Das, Nirmoy:
>>>
>>> On 6/21/2021 12:26 PM, Christian König wrote:
>>>> Well you completely break the handling in amdgpu_vm_handle_fault() 
>>>> with this.
>>>
>>>
>>> I see one issue with:  if (!vm || (vm && vm->root.bo != root)) . I 
>>> will split it and resend.
>>>
>>> Am I missing something else ?
>>
>> The problem is you drop and re-take the lock now at the wrong time.
>
>
> The original code is also dropping and retaking the lock.  I don't 
> understand the difference.

> spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
> vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
> if (vm) {
>     root = amdgpu_bo_ref(vm->root.bo);
>     is_compute_context = vm->is_compute_context;
> } else {
>     root = NULL;
> }
> spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);

What this code does is not only looking up the VM, but also taking a 
reference to the root PD.

This must both be done while holding the lock.

Christian.

>
>
> Regards,
>
> Nirmoy
>
>>
>> I don't think what you try to do here is possible at all.
>>
>> Christian.
>>
>>>
>>>
>>> Regards,
>>>
>>> Nirmoy
>>>
>>>
>>>
>>>>
>>>> Christian.
>>>>
>>>> Am 21.06.21 um 11:47 schrieb Das, Nirmoy:
>>>>> ping.
>>>>>
>>>>> On 6/17/2021 3:03 PM, Nirmoy Das wrote:
>>>>>> Cleanup code related to vm pasid by adding helper function.
>>>>>> This reduces lots code duplication.
>>>>>>
>>>>>> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
>>>>>> ---
>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c |  17 +--
>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 176 
>>>>>> ++++++++++++------------
>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h  |   2 +-
>>>>>>   3 files changed, 96 insertions(+), 99 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c 
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
>>>>>> index cbb932f97355..27851fb0e25b 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
>>>>>> @@ -1149,7 +1149,7 @@ int amdgpu_driver_open_kms(struct 
>>>>>> drm_device *dev, struct drm_file *file_priv)
>>>>>>   {
>>>>>>       struct amdgpu_device *adev = drm_to_adev(dev);
>>>>>>       struct amdgpu_fpriv *fpriv;
>>>>>> -    int r, pasid;
>>>>>> +    int r;
>>>>>>         /* Ensure IB tests are run on ring */
>>>>>> flush_delayed_work(&adev->delayed_init_work);
>>>>>> @@ -1172,15 +1172,9 @@ int amdgpu_driver_open_kms(struct 
>>>>>> drm_device *dev, struct drm_file *file_priv)
>>>>>>           goto out_suspend;
>>>>>>       }
>>>>>>   -    pasid = amdgpu_pasid_alloc(16);
>>>>>> -    if (pasid < 0) {
>>>>>> -        dev_warn(adev->dev, "No more PASIDs available!");
>>>>>> -        pasid = 0;
>>>>>> -    }
>>>>>> -
>>>>>> -    r = amdgpu_vm_init(adev, &fpriv->vm, pasid);
>>>>>> +    r = amdgpu_vm_init(adev, &fpriv->vm);
>>>>>>       if (r)
>>>>>> -        goto error_pasid;
>>>>>> +        goto free_fpriv;
>>>>>>         fpriv->prt_va = amdgpu_vm_bo_add(adev, &fpriv->vm, NULL);
>>>>>>       if (!fpriv->prt_va) {
>>>>>> @@ -1208,10 +1202,7 @@ int amdgpu_driver_open_kms(struct 
>>>>>> drm_device *dev, struct drm_file *file_priv)
>>>>>>   error_vm:
>>>>>>       amdgpu_vm_fini(adev, &fpriv->vm);
>>>>>>   -error_pasid:
>>>>>> -    if (pasid)
>>>>>> -        amdgpu_pasid_free(pasid);
>>>>>> -
>>>>>> +free_fpriv:
>>>>>>       kfree(fpriv);
>>>>>>     out_suspend:
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> index 63975bda8e76..562c2c48a3a3 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>>>> @@ -87,6 +87,69 @@ struct amdgpu_prt_cb {
>>>>>>       struct dma_fence_cb cb;
>>>>>>   };
>>>>>>   +static int amdgpu_vm_pasid_alloc(struct amdgpu_device *adev,
>>>>>> +                 struct amdgpu_vm *vm, unsigned int pasid)
>>>>>> +{
>>>>>> +    unsigned long flags;
>>>>>> +    int r;
>>>>>> +
>>>>>> +    if (!pasid)
>>>>>> +        return 0;
>>>>>> +
>>>>>> + spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> +    r = idr_alloc(&adev->vm_manager.pasid_idr, vm, pasid, pasid 
>>>>>> + 1,
>>>>>> +              GFP_ATOMIC);
>>>>>> + spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> +    if (r < 0)
>>>>>> +        return r;
>>>>>> +
>>>>>> +    vm->pasid = pasid;
>>>>>> +    return 0;
>>>>>> +}
>>>>>> +static void amdgpu_vm_pasid_remove_id(struct amdgpu_device *adev,
>>>>>> +                      unsigned int pasid)
>>>>>> +{
>>>>>> +    unsigned long flags;
>>>>>> +
>>>>>> +    if (!pasid)
>>>>>> +        return;
>>>>>> +
>>>>>> + spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> +    idr_remove(&adev->vm_manager.pasid_idr, pasid);
>>>>>> + spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> +
>>>>>> +}
>>>>>> +
>>>>>> +static void amdgpu_vm_pasid_remove(struct amdgpu_device *adev,
>>>>>> +                   struct amdgpu_vm *vm)
>>>>>> +{
>>>>>> +    amdgpu_vm_pasid_remove_id(adev, vm->pasid);
>>>>>> +    vm->pasid = 0;
>>>>>> +}
>>>>>> +
>>>>>> +static void amdgpu_vm_pasid_free(struct amdgpu_device *adev,
>>>>>> +                 struct amdgpu_vm *vm)
>>>>>> +{
>>>>>> +    if (!vm->pasid)
>>>>>> +        return;
>>>>>> +
>>>>>> +    amdgpu_pasid_free(vm->pasid);
>>>>>> +    amdgpu_vm_pasid_remove(adev, vm);
>>>>>> +}
>>>>>> +
>>>>>> +static struct amdgpu_vm *amdgpu_vm_pasid_find(struct 
>>>>>> amdgpu_device *adev,
>>>>>> +                          unsigned int pasid)
>>>>>> +{
>>>>>> +    struct amdgpu_vm *vm;
>>>>>> +    unsigned long flags;
>>>>>> +
>>>>>> + spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> +    vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>>>>>> + spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> +
>>>>>> +    return vm;
>>>>>> +}
>>>>>> +
>>>>>>   /*
>>>>>>    * vm eviction_lock can be taken in MMU notifiers. Make sure no 
>>>>>> reclaim-FS
>>>>>>    * happens while holding this lock anywhere to prevent 
>>>>>> deadlocks when
>>>>>> @@ -2859,17 +2922,17 @@ long amdgpu_vm_wait_idle(struct amdgpu_vm 
>>>>>> *vm, long timeout)
>>>>>>    *
>>>>>>    * @adev: amdgpu_device pointer
>>>>>>    * @vm: requested vm
>>>>>> - * @pasid: Process address space identifier
>>>>>>    *
>>>>>>    * Init @vm fields.
>>>>>>    *
>>>>>>    * Returns:
>>>>>>    * 0 for success, error for failure.
>>>>>>    */
>>>>>> -int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm 
>>>>>> *vm, u32 pasid)
>>>>>> +int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm 
>>>>>> *vm)
>>>>>>   {
>>>>>>       struct amdgpu_bo *root_bo;
>>>>>>       struct amdgpu_bo_vm *root;
>>>>>> +    unsigned int pasid;
>>>>>>       int r, i;
>>>>>>         vm->va = RB_ROOT_CACHED;
>>>>>> @@ -2940,19 +3003,15 @@ int amdgpu_vm_init(struct amdgpu_device 
>>>>>> *adev, struct amdgpu_vm *vm, u32 pasid)
>>>>>>         amdgpu_bo_unreserve(vm->root.bo);
>>>>>>   -    if (pasid) {
>>>>>> -        unsigned long flags;
>>>>>> -
>>>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        r = idr_alloc(&adev->vm_manager.pasid_idr, vm, pasid, 
>>>>>> pasid + 1,
>>>>>> -                  GFP_ATOMIC);
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        if (r < 0)
>>>>>> -            goto error_free_root;
>>>>>> -
>>>>>> -        vm->pasid = pasid;
>>>>>> +    pasid = amdgpu_pasid_alloc(16);
>>>>>> +    if (pasid < 0) {
>>>>>> +        dev_warn(adev->dev, "No more PASIDs available!");
>>>>>> +        pasid = 0;
>>>>>>       }
>>>>>>   +    if (amdgpu_vm_pasid_alloc(adev, vm, pasid))
>>>>>> +        goto error_free_pasid;
>>>>>> +
>>>>>>       INIT_KFIFO(vm->faults);
>>>>>>         return 0;
>>>>>> @@ -2960,6 +3019,10 @@ int amdgpu_vm_init(struct amdgpu_device 
>>>>>> *adev, struct amdgpu_vm *vm, u32 pasid)
>>>>>>   error_unreserve:
>>>>>>       amdgpu_bo_unreserve(vm->root.bo);
>>>>>>   +error_free_pasid:
>>>>>> +    if (pasid)
>>>>>> +        amdgpu_pasid_free(pasid);
>>>>>> +
>>>>>>   error_free_root:
>>>>>>       amdgpu_bo_unref(&root->shadow);
>>>>>>       amdgpu_bo_unref(&root_bo);
>>>>>> @@ -3039,18 +3102,11 @@ int amdgpu_vm_make_compute(struct 
>>>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>>>>       if (r)
>>>>>>           goto unreserve_bo;
>>>>>>   -    if (pasid) {
>>>>>> -        unsigned long flags;
>>>>>> -
>>>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        r = idr_alloc(&adev->vm_manager.pasid_idr, vm, pasid, 
>>>>>> pasid + 1,
>>>>>> -                  GFP_ATOMIC);
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> +    r = amdgpu_vm_pasid_alloc(adev, vm, pasid);
>>>>>> +    if (r ==  -ENOSPC)
>>>>>> +        goto unreserve_bo;
>>>>>>   -        if (r == -ENOSPC)
>>>>>> -            goto unreserve_bo;
>>>>>> -        r = 0;
>>>>>> -    }
>>>>>> +    r = 0;
>>>>>>         /* Check if PD needs to be reinitialized and do it before
>>>>>>        * changing any other state, in case it fails.
>>>>>> @@ -3088,19 +3144,7 @@ int amdgpu_vm_make_compute(struct 
>>>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>>>>       vm->last_update = NULL;
>>>>>>       vm->is_compute_context = true;
>>>>>>   -    if (vm->pasid) {
>>>>>> -        unsigned long flags;
>>>>>> -
>>>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> -
>>>>>> -        /* Free the original amdgpu allocated pasid
>>>>>> -         * Will be replaced with kfd allocated pasid
>>>>>> -         */
>>>>>> -        amdgpu_pasid_free(vm->pasid);
>>>>>> -        vm->pasid = 0;
>>>>>> -    }
>>>>>> +    amdgpu_vm_pasid_free(adev, vm);
>>>>>>         /* Free the shadow bo for compute VM */
>>>>>> amdgpu_bo_unref(&to_amdgpu_bo_vm(vm->root.bo)->shadow);
>>>>>> @@ -3111,13 +3155,8 @@ int amdgpu_vm_make_compute(struct 
>>>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>>>>       goto unreserve_bo;
>>>>>>     free_idr:
>>>>>> -    if (pasid) {
>>>>>> -        unsigned long flags;
>>>>>> +    amdgpu_vm_pasid_remove_id(adev, pasid);
>>>>>>   - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        idr_remove(&adev->vm_manager.pasid_idr, pasid);
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> -    }
>>>>>>   unreserve_bo:
>>>>>>       amdgpu_bo_unreserve(vm->root.bo);
>>>>>>       return r;
>>>>>> @@ -3133,14 +3172,7 @@ int amdgpu_vm_make_compute(struct 
>>>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>>>>    */
>>>>>>   void amdgpu_vm_release_compute(struct amdgpu_device *adev, 
>>>>>> struct amdgpu_vm *vm)
>>>>>>   {
>>>>>> -    if (vm->pasid) {
>>>>>> -        unsigned long flags;
>>>>>> -
>>>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> -    }
>>>>>> -    vm->pasid = 0;
>>>>>> +    amdgpu_vm_pasid_remove(adev, vm);
>>>>>>       vm->is_compute_context = false;
>>>>>>   }
>>>>>>   @@ -3164,15 +3196,7 @@ void amdgpu_vm_fini(struct amdgpu_device 
>>>>>> *adev, struct amdgpu_vm *vm)
>>>>>>         root = amdgpu_bo_ref(vm->root.bo);
>>>>>>       amdgpu_bo_reserve(root, true);
>>>>>> -    if (vm->pasid) {
>>>>>> -        unsigned long flags;
>>>>>> -
>>>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>> -        vm->pasid = 0;
>>>>>> -    }
>>>>>> -
>>>>>> +    amdgpu_vm_pasid_remove(adev, vm);
>>>>>>       dma_fence_wait(vm->last_unlocked, false);
>>>>>>       dma_fence_put(vm->last_unlocked);
>>>>>>   @@ -3334,16 +3358,10 @@ int amdgpu_vm_ioctl(struct drm_device 
>>>>>> *dev, void *data, struct drm_file *filp)
>>>>>>   void amdgpu_vm_get_task_info(struct amdgpu_device *adev, u32 
>>>>>> pasid,
>>>>>>                struct amdgpu_task_info *task_info)
>>>>>>   {
>>>>>> -    struct amdgpu_vm *vm;
>>>>>> -    unsigned long flags;
>>>>>> +    struct amdgpu_vm *vm = amdgpu_vm_pasid_find(adev, pasid);
>>>>>>   - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>>>> -
>>>>>> -    vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>>>>>>       if (vm)
>>>>>>           *task_info = vm->task_info;
>>>>>> -
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>>>>   }
>>>>>>     /**
>>>>>> @@ -3380,24 +3398,16 @@ bool amdgpu_vm_handle_fault(struct 
>>>>>> amdgpu_device *adev, u32 pasid,
>>>>>>   {
>>>>>>       bool is_compute_context = false;
>>>>>>       struct amdgpu_bo *root;
>>>>>> -    unsigned long irqflags;
>>>>>>       uint64_t value, flags;
>>>>>>       struct amdgpu_vm *vm;
>>>>>>       int r;
>>>>>>   - spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
>>>>>> -    vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>>>>>> -    if (vm) {
>>>>>> -        root = amdgpu_bo_ref(vm->root.bo);
>>>>>> -        is_compute_context = vm->is_compute_context;
>>>>>> -    } else {
>>>>>> -        root = NULL;
>>>>>> -    }
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);
>>>>>> -
>>>>>> -    if (!root)
>>>>>> +    vm = amdgpu_vm_pasid_find(adev, pasid);
>>>>>> +    if (!vm)
>>>>>>           return false;
>>>>>>   +    root = amdgpu_bo_ref(vm->root.bo);
>>>>>> +        is_compute_context = vm->is_compute_context;
>>>>>>       addr /= AMDGPU_GPU_PAGE_SIZE;
>>>>>>         if (is_compute_context &&
>>>>>> @@ -3411,12 +3421,8 @@ bool amdgpu_vm_handle_fault(struct 
>>>>>> amdgpu_device *adev, u32 pasid,
>>>>>>           goto error_unref;
>>>>>>         /* Double check that the VM still exists */
>>>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
>>>>>> -    vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>>>>>> -    if (vm && vm->root.bo != root)
>>>>>> -        vm = NULL;
>>>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);
>>>>>> -    if (!vm)
>>>>>> +    vm = amdgpu_vm_pasid_find(adev, pasid);
>>>>>> +    if (!vm || (vm && vm->root.bo != root))
>>>>>>           goto error_unlock;
>>>>>>         flags = AMDGPU_PTE_VALID | AMDGPU_PTE_SNOOPED |
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h 
>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>>>>>> index ddb85a85cbba..ee994e21dffa 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>>>>>> @@ -376,7 +376,7 @@ void amdgpu_vm_manager_init(struct 
>>>>>> amdgpu_device *adev);
>>>>>>   void amdgpu_vm_manager_fini(struct amdgpu_device *adev);
>>>>>>     long amdgpu_vm_wait_idle(struct amdgpu_vm *vm, long timeout);
>>>>>> -int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm 
>>>>>> *vm, u32 pasid);
>>>>>> +int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm 
>>>>>> *vm);
>>>>>>   int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct 
>>>>>> amdgpu_vm *vm, u32 pasid);
>>>>>>   void amdgpu_vm_release_compute(struct amdgpu_device *adev, 
>>>>>> struct amdgpu_vm *vm);
>>>>>>   void amdgpu_vm_fini(struct amdgpu_device *adev, struct 
>>>>>> amdgpu_vm *vm);
>>>>
>>
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