[PATCH 3/3] drm/xe/uapi: Introduce VMA bind flag for device atomics
Lionel Landwerlin
lionel.g.landwerlin at intel.com
Thu Apr 11 14:00:32 UTC 2024
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
>
>
> 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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