[PATCH 3/3] drm/xe/uapi: Introduce VMA bind flag for device atomics
Nirmoy Das
nirmoy.das at intel.com
Thu Apr 11 14:54:30 UTC 2024
Hi Jose,
On 4/11/2024 4:40 PM, Souza, Jose wrote:
> On Thu, 2024-04-11 at 16:32 +0200, Nirmoy Das wrote:
>> Hi Jose,
>>
>> On 4/11/2024 4:07 PM, Souza, Jose wrote:
>>> On Thu, 2024-04-11 at 17:00 +0300, Lionel Landwerlin wrote:
>>>> On 11/04/2024 16:42, Nirmoy Das wrote:
>>>>> Hi Lionel,
>>>>>
>>>>> On 4/11/2024 3:14 PM, Lionel Landwerlin wrote:
>>>>>> On 10/04/2024 20:03, Nirmoy Das wrote:
>>>>>>> Adds a new VMA bind flag to enable device atomics on SMEM only buffers.
>>>>>>>
>>>>>>> Given that simultaneous usage of device atomics and CPU atomics on
>>>>>>> the same SMEM buffer is not guaranteed to function without migration,
>>>>>>> and UMD expects no migration for SMEM-only buffer objects, so this
>>>>>>> provide
>>>>>>> a way to set device atomics when UMD is certain to use the buffer only
>>>>>>> for device atomics.
>>>>>>>
>>>>>>> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
>>>>>>> ---
>>>>>>> drivers/gpu/drm/xe/xe_vm.c | 27 +++++++++++++++++++++++++--
>>>>>>> drivers/gpu/drm/xe/xe_vm_types.h | 2 ++
>>>>>>> include/uapi/drm/xe_drm.h | 9 +++++----
>>>>>>> 3 files changed, 32 insertions(+), 6 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
>>>>>>> index 8f3474c5f480..530b4bbc186c 100644
>>>>>>> --- a/drivers/gpu/drm/xe/xe_vm.c
>>>>>>> +++ b/drivers/gpu/drm/xe/xe_vm.c
>>>>>>> @@ -851,6 +851,7 @@ static void xe_vma_free(struct xe_vma *vma)
>>>>>>> #define VMA_CREATE_FLAG_READ_ONLY BIT(0)
>>>>>>> #define VMA_CREATE_FLAG_IS_NULL BIT(1)
>>>>>>> #define VMA_CREATE_FLAG_DUMPABLE BIT(2)
>>>>>>> +#define VMA_CREATE_FLAG_DEVICE_ATOMICS BIT(3)
>>>>>>> static struct xe_vma *xe_vma_create(struct xe_vm *vm,
>>>>>>> struct xe_bo *bo,
>>>>>>> @@ -864,6 +865,7 @@ static struct xe_vma *xe_vma_create(struct xe_vm
>>>>>>> *vm,
>>>>>>> bool read_only = (flags & VMA_CREATE_FLAG_READ_ONLY);
>>>>>>> bool is_null = (flags & VMA_CREATE_FLAG_IS_NULL);
>>>>>>> bool dumpable = (flags & VMA_CREATE_FLAG_DUMPABLE);
>>>>>>> + bool enable_atomics = (flags & VMA_CREATE_FLAG_IS_NULL);
>>>>>>> xe_assert(vm->xe, start < end);
>>>>>>> xe_assert(vm->xe, end < vm->size);
>>>>>>> @@ -912,7 +914,7 @@ static struct xe_vma *xe_vma_create(struct xe_vm
>>>>>>> *vm,
>>>>>>> xe_bo_assert_held(bo);
>>>>>>> if (GRAPHICS_VER(vm->xe) >= 20 || xe_bo_is_vram(bo) ||
>>>>>>> - !IS_DGFX(vm->xe))
>>>>>>> + !IS_DGFX(vm->xe) || enable_atomics)
>>>>>>> vma->gpuva.flags |= XE_VMA_ATOMIC_PTE_BIT;
>>>>>>> vm_bo = drm_gpuvm_bo_obtain(vma->gpuva.vm, &bo->ttm.base);
>>>>>>> @@ -2174,6 +2176,18 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm,
>>>>>>> struct xe_bo *bo,
>>>>>>> operation, (ULL)addr, (ULL)range,
>>>>>>> (ULL)bo_offset_or_userptr);
>>>>>>> + if (bo && (flags & DRM_XE_VM_BIND_FLAG_DEVICE_ATOMICS) &&
>>>>>>> + (vm->xe->info.platform == XE_PVC && !xe_bo_is_vram(bo))) {
>>>>>>> + drm_warn(&vm->xe->drm, "Setting device atomics on SMEM is
>>>>>>> not supported for this platform");
>>>>>>> + return ERR_PTR(-EINVAL);
>>>>>>> + }
>>>>>>> +
>>>>>>> + if (bo && (flags & DRM_XE_VM_BIND_FLAG_DEVICE_ATOMICS) &&
>>>>>>> + !xe_bo_has_single_placement(bo))
>>>>>>> + drm_warn(&vm->xe->drm, "DRM_XE_VM_BIND_FLAG_DEVICE_ATOMICS
>>>>>>> can be only set if the BO has single placement");
>>>>>>> + return ERR_PTR(-EINVAL);
>>>>>>> + }
>>>>>>> +
>>>>>>> switch (operation) {
>>>>>>> case DRM_XE_VM_BIND_OP_MAP:
>>>>>>> case DRM_XE_VM_BIND_OP_MAP_USERPTR:
>>>>>>> @@ -2216,6 +2230,7 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm,
>>>>>>> struct xe_bo *bo,
>>>>>>> if (__op->op == DRM_GPUVA_OP_MAP) {
>>>>>>> op->map.is_null = flags & DRM_XE_VM_BIND_FLAG_NULL;
>>>>>>> op->map.dumpable = flags & DRM_XE_VM_BIND_FLAG_DUMPABLE;
>>>>>>> + op->map.enable_device_atomics = flags &
>>>>>>> DRM_XE_VM_BIND_FLAG_DEVICE_ATOMICS;
>>>>>>> op->map.pat_index = pat_index;
>>>>>>> } else if (__op->op == DRM_GPUVA_OP_PREFETCH) {
>>>>>>> op->prefetch.region = prefetch_region;
>>>>>>> @@ -2412,6 +2427,8 @@ static int vm_bind_ioctl_ops_parse(struct
>>>>>>> xe_vm *vm, struct xe_exec_queue *q,
>>>>>>> VMA_CREATE_FLAG_IS_NULL : 0;
>>>>>>> flags |= op->map.dumpable ?
>>>>>>> VMA_CREATE_FLAG_DUMPABLE : 0;
>>>>>>> + flags |= op->map.enable_device_atomics ?
>>>>>>> + VMA_CREATE_FLAG_DEVICE_ATOMICS : 0;
>>>>>>> vma = new_vma(vm, &op->base.map, op->map.pat_index,
>>>>>>> flags);
>>>>>>> @@ -2439,6 +2456,8 @@ static int vm_bind_ioctl_ops_parse(struct
>>>>>>> xe_vm *vm, struct xe_exec_queue *q,
>>>>>>> flags |= op->base.remap.unmap->va->flags &
>>>>>>> XE_VMA_DUMPABLE ?
>>>>>>> VMA_CREATE_FLAG_DUMPABLE : 0;
>>>>>>> + flags |= op->base.remap.unmap->va->flags ?
>>>>>>> + VMA_CREATE_FLAG_DEVICE_ATOMICS : 0;
>>>>>>> vma = new_vma(vm, op->base.remap.prev,
>>>>>>> old->pat_index, flags);
>>>>>>> @@ -2476,6 +2495,9 @@ static int vm_bind_ioctl_ops_parse(struct
>>>>>>> xe_vm *vm, struct xe_exec_queue *q,
>>>>>>> flags |= op->base.remap.unmap->va->flags &
>>>>>>> XE_VMA_DUMPABLE ?
>>>>>>> VMA_CREATE_FLAG_DUMPABLE : 0;
>>>>>>> + flags |= op->base.remap.unmap->va->flags ?
>>>>>>> + VMA_CREATE_FLAG_DEVICE_ATOMICS : 0;
>>>>>>> +
>>>>>>> vma = new_vma(vm, op->base.remap.next,
>>>>>>> old->pat_index, flags);
>>>>>>> @@ -2831,7 +2853,8 @@ static int vm_bind_ioctl_ops_execute(struct
>>>>>>> xe_vm *vm,
>>>>>>> (DRM_XE_VM_BIND_FLAG_READONLY | \
>>>>>>> DRM_XE_VM_BIND_FLAG_IMMEDIATE | \
>>>>>>> DRM_XE_VM_BIND_FLAG_NULL | \
>>>>>>> - DRM_XE_VM_BIND_FLAG_DUMPABLE)
>>>>>>> + DRM_XE_VM_BIND_FLAG_DUMPABLE | \
>>>>>>> + DRM_XE_VM_BIND_FLAG_DEVICE_ATOMICS)
>>>>>>> #define XE_64K_PAGE_MASK 0xffffull
>>>>>>> #define ALL_DRM_XE_SYNCS_FLAGS (DRM_XE_SYNCS_FLAG_WAIT_FOR_OP)
>>>>>>> diff --git a/drivers/gpu/drm/xe/xe_vm_types.h
>>>>>>> b/drivers/gpu/drm/xe/xe_vm_types.h
>>>>>>> index badf3945083d..7b9c68909c78 100644
>>>>>>> --- a/drivers/gpu/drm/xe/xe_vm_types.h
>>>>>>> +++ b/drivers/gpu/drm/xe/xe_vm_types.h
>>>>>>> @@ -282,6 +282,8 @@ struct xe_vma_op_map {
>>>>>>> bool dumpable;
>>>>>>> /** @pat_index: The pat index to use for this operation. */
>>>>>>> u16 pat_index;
>>>>>>> + /** @enable_device_atomics: Whether the VMA will allow device
>>>>>>> atomics */
>>>>>>> + bool enable_device_atomics;
>>>>>>> };
>>>>>>> /** struct xe_vma_op_remap - VMA remap operation */
>>>>>>> diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
>>>>>>> index 1446c3bae515..bffe8b1c040c 100644
>>>>>>> --- a/include/uapi/drm/xe_drm.h
>>>>>>> +++ b/include/uapi/drm/xe_drm.h
>>>>>>> @@ -969,10 +969,11 @@ struct drm_xe_vm_bind_op {
>>>>>>> /** @op: Bind operation to perform */
>>>>>>> __u32 op;
>>>>>>> -#define DRM_XE_VM_BIND_FLAG_READONLY (1 << 0)
>>>>>>> -#define DRM_XE_VM_BIND_FLAG_IMMEDIATE (1 << 1)
>>>>>>> -#define DRM_XE_VM_BIND_FLAG_NULL (1 << 2)
>>>>>>> -#define DRM_XE_VM_BIND_FLAG_DUMPABLE (1 << 3)
>>>>>>> +#define DRM_XE_VM_BIND_FLAG_READONLY (1 << 0)
>>>>>>> +#define DRM_XE_VM_BIND_FLAG_IMMEDIATE (1 << 1)
>>>>>>> +#define DRM_XE_VM_BIND_FLAG_NULL (1 << 2)
>>>>>>> +#define DRM_XE_VM_BIND_FLAG_DUMPABLE (1 << 3)
>>>>>> We should probably document that it's an error to add this flag if
>>>>>> the BO has a single memory region.
>>>>> It is an error if this flag is set on non single memory region as
>>>>> atomics on SMEM+LMEM buffer will be handled with migration.
>>>>>
>>>>> Let me know if I got that wrong.
>>>>>
>>>>>> Are we supposed to the ability to set that flag or is there going to
>>>>>> be a query?
>>>>>>
>>>>>> A query might make sense since it's going to be rejected for some
>>>>>> platform.
>>>>> Can we use the rejection as a query ? I am using it in a IGT test
>>>>> https://patchwork.freedesktop.org/patch/588759/?series=132289&rev=1
>>>>>
>>>>>
>>> That was not acceptable for DRM_XE_VM_BIND_FLAG_DUMPABLE. At the end we were able to land DRM_XE_VM_BIND_FLAG_DUMPABLE in Linux 6.8 so we did not
>>> needed the query. But for this one will be needed.
>> If the rejection can't work as query, I can add one. Would
>> adding(DRM_XE_QUERY_CONFIG_SUPP_DEV_ATOMIC_ON_SMEM) a new flag into
>> 'struct drm_xe_query_config' work ?
> As another bit after DRM_XE_QUERY_CONFIG_FLAG_HAS_VRAM?
Yes.
> That lgtm but even better would be add a new category like
> DRM_XE_QUERY_CONFIG_SUPPORTED_FEATURES and then DRM_XE_QUERY_CONFIG_SUPPORTED_FEATURES_ATOMIC_ON_SMEM (1 << 0).
> So we have a u64 just to check for features supported by different KMD versions.
>
> But ask the opinion of other engineers in Xe chat.
Done. Let's see what others prefer.
Thanks,
Nirmoy
>
>>
>> Regards,
>>
>> Nirmoy
>>
>>>
>>>>> Regards,
>>>>>
>>>>> Nirmoy
>>>> Okay, sounds doable.
>>>>
>>>> Will try to put up an MR for Mesa soon.
>>>>
>>>>
>>>> -Lionel
>>>>
>>>>
>>>>>> -Lionel
>>>>>>
>>>>>>
>>>>>>> +#define DRM_XE_VM_BIND_FLAG_DEVICE_ATOMICS (1 << 4)
>>>>>>> /** @flags: Bind flags */
>>>>>>> __u32 flags;
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