[RFC 10/29] drm/xe/svm: Refactor usage of drm_gpusvm* function in xe_svm
Ghimiray, Himal Prasad
himal.prasad.ghimiray at intel.com
Mon Apr 7 06:15:04 UTC 2025
On 04-04-2025 02:24, Matthew Brost wrote:
> On Fri, Mar 14, 2025 at 01:32:07PM +0530, Himal Prasad Ghimiray wrote:
>> Define xe_svm_range_find_or_insert function wrapping
>> drm_gpusvm_range_find_or_insert for reusing in prefetch.
>>
>> Define xe_svm_range_get_pages function wrapping
>> drm_gpusvm_range_get_pages for reusing in prefetch.
>>
>> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
>> ---
>> drivers/gpu/drm/xe/xe_svm.c | 73 +++++++++++++++++++++++++++++++------
>> drivers/gpu/drm/xe/xe_svm.h | 20 ++++++++++
>> 2 files changed, 81 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
>> index 07511011aba6..5a4cb14d608e 100644
>> --- a/drivers/gpu/drm/xe/xe_svm.c
>> +++ b/drivers/gpu/drm/xe/xe_svm.c
>> @@ -714,7 +714,6 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
>> IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR) ? SZ_64K : 0,
>> };
>> struct xe_svm_range *range;
>> - struct drm_gpusvm_range *r;
>> struct drm_exec exec;
>> struct dma_fence *fence;
>> ktime_t end = 0;
>> @@ -729,13 +728,11 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
>> if (err)
>> return err;
>>
>> - r = drm_gpusvm_range_find_or_insert(&vm->svm.gpusvm, fault_addr,
>> - xe_vma_start(vma), xe_vma_end(vma),
>> - &ctx);
>> - if (IS_ERR(r))
>> - return PTR_ERR(r);
>> + range = xe_svm_range_find_or_insert(vm, fault_addr, vma);
>> +
>> + if (IS_ERR(range))
>> + return PTR_ERR(range);
>>
>> - range = to_xe_range(r);
>> if (xe_svm_range_is_valid(range, tile))
>> return 0;
>>
>> @@ -757,13 +754,9 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
>> }
>>
>> range_debug(range, "GET PAGES");
>> - err = drm_gpusvm_range_get_pages(&vm->svm.gpusvm, r, &ctx);
>> + err = xe_svm_range_get_pages(vm, range, &ctx);
>> /* Corner where CPU mappings have changed */
>> if (err == -EOPNOTSUPP || err == -EFAULT || err == -EPERM) {
>> - if (err == -EOPNOTSUPP) {
>> - range_debug(range, "PAGE FAULT - EVICT PAGES");
>> - drm_gpusvm_range_evict(&vm->svm.gpusvm, &range->base);
>> - }
>> drm_dbg(&vm->xe->drm,
>> "Get pages failed, falling back to retrying, asid=%u, gpusvm=%p, errno=%pe\n",
>> vm->usm.asid, &vm->svm.gpusvm, ERR_PTR(err));
>> @@ -842,6 +835,62 @@ int xe_svm_bo_evict(struct xe_bo *bo)
>> return drm_gpusvm_evict_to_ram(&bo->devmem_allocation);
>> }
>>
>> +/**
>> + * xe_svm_range_find_or_insert- Find or insert GPU SVM range
>> + * @vm: xe_vm pointer
>> + * @addr: address for which range needs to be found/inserted
>> + * @vma: Pointer to struct xe_vma which mirrors CPU
>> + *
>> + * This function finds or inserts a newly allocated a SVM range based on the
>> + * address.
>> + *
>> + * Return: Pointer to the SVM range on success, ERR_PTR() on failure.
>> + */
>> +struct xe_svm_range *xe_svm_range_find_or_insert(struct xe_vm *vm, u64 addr,
>> + struct xe_vma *vma)
>
> I think you want a drm_gpusvm_ctx argument here. It is odd to duplicate
> the context locally when the page fault handler has already set one up.
Makes sense. will fix in next version.
>
> Matt
>
>> +{
>> + struct drm_gpusvm_range *r;
>> +
>> + struct drm_gpusvm_ctx ctx = {
>> + .read_only = xe_vma_read_only(vma),
>> + .devmem_possible = IS_DGFX(vm->xe) && IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR),
>> + .check_pages_threshold = IS_DGFX(vm->xe) &&
>> + IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR) ? SZ_64K : 0,
>> + };
>> +
>> + r = drm_gpusvm_range_find_or_insert(&vm->svm.gpusvm, max(addr, xe_vma_start(vma)),
>> + xe_vma_start(vma), xe_vma_end(vma), &ctx);
>> + if (IS_ERR(r))
>> + return ERR_PTR(PTR_ERR(r));
>> +
>> + return to_xe_range(r);
>> +}
>> +
>> +/**
>> + * xe_svm_range_get_pages() - Get pages for a SVM range
>> + * @vm: Pointer to the struct xe_vm
>> + * @range: Pointer to the xe SVM range structure
>> + * @ctx: GPU SVM context
>> + *
>> + * This function gets pages for a SVM range and ensures they are mapped for
>> + * DMA access. In case of failure with -EOPNOTSUPP, it evicts the range.
>> + *
>> + * Return: 0 on success, negative error code on failure.
>> + */
>> +int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range,
>> + struct drm_gpusvm_ctx *ctx)
>> +{
>> + int err = 0;
>> +
>> + err = drm_gpusvm_range_get_pages(&vm->svm.gpusvm, &range->base, ctx);
>> + if (err == -EOPNOTSUPP) {
>> + range_debug(range, "PAGE FAULT - EVICT PAGES");
>> + drm_gpusvm_range_evict(&vm->svm.gpusvm, &range->base);
>> + }
>> +
>> + return err;
>> +}
>> +
>> #if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
>> static struct drm_pagemap_device_addr
>> xe_drm_pagemap_device_map(struct drm_pagemap *dpagemap,
>> diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
>> index c8add37614ec..6bb358bf62ad 100644
>> --- a/drivers/gpu/drm/xe/xe_svm.h
>> +++ b/drivers/gpu/drm/xe/xe_svm.h
>> @@ -76,6 +76,12 @@ void xe_svm_range_debug(struct xe_svm_range *range, const char *operation);
>> int xe_svm_alloc_vram(struct xe_vm *vm, struct xe_tile *tile,
>> struct xe_svm_range *range,
>> const struct drm_gpusvm_ctx *ctx);
>> +
>> +struct xe_svm_range *xe_svm_range_find_or_insert(struct xe_vm *vm, u64 addr,
>> + struct xe_vma *vma);
>> +
>> +int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range,
>> + struct drm_gpusvm_ctx *ctx);
>> #else
>> static inline bool xe_svm_range_pages_valid(struct xe_svm_range *range)
>> {
>> @@ -137,6 +143,20 @@ int xe_svm_alloc_vram(struct xe_vm *vm, struct xe_tile *tile,
>> return 0;
>> }
>>
>> +static inline
>> +struct xe_svm_range *xe_svm_range_find_or_insert(struct xe_vm *vm, u64 addr,
>> + struct xe_vma *vma)
>> +{
>> + return ERR_PTR(-EINVAL);
>> +}
>> +
>> +static inline
>> +int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range,
>> + struct drm_gpusvm_ctx *ctx)
>> +{
>> + return -EINVAL;
>> +}
>> +
>> #endif
>>
>> /**
>> --
>> 2.34.1
>>
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