[PATCH v2 24/32] drm/xe: Allow CPU address mirror VMA unbind with gpu bindings for madvise

[Matthew Brost]

On Mon, Apr 07, 2025 at 03:47:11PM +0530, Himal Prasad Ghimiray wrote:
> In the case of the MADVISE ioctl, if the start or end addresses fall
> within a VMA and existing SVM ranges are present, remove the existing
> SVM mappings. Then, continue with ops_parse to create new VMAs by REMAP
> unmapping of old one.
> 

I'm quite confused why this patch is needed. Why is invalidating the
ranges not sufficient?

Matt

> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_svm.c | 25 +++++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_svm.h |  7 +++++++
>  drivers/gpu/drm/xe/xe_vm.c  | 18 +++++++++++++++++-
>  3 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
> index 7ec7ecd7eb1f..efcba4b77250 100644
> --- a/drivers/gpu/drm/xe/xe_svm.c
> +++ b/drivers/gpu/drm/xe/xe_svm.c
> @@ -903,6 +903,31 @@ bool xe_svm_has_mapping(struct xe_vm *vm, u64 start, u64 end)
>  	return drm_gpusvm_has_mapping(&vm->svm.gpusvm, start, end);
>  }
>  
> +/**
> + * xe_svm_range_clean_if_addr_within - Clean SVM mappings and ranges
> + * @start: start addr
> + * @end: end addr
> + *
> + * This function cleans up svm ranges if start or end address are inside them.
> + */
> +void xe_svm_range_clean_if_addr_within(struct xe_vm *vm, u64 start, u64 end)
> +{
> +	struct drm_gpusvm_notifier *notifier, *next;
> +
> +	drm_gpusvm_for_each_notifier_safe(notifier, next, &vm->svm.gpusvm, start, end) {
> +		struct drm_gpusvm_range *range, *__next;
> +
> +		drm_gpusvm_for_each_range_safe(range, __next, notifier, start, end) {
> +			if (start > drm_gpusvm_range_start(range) ||
> +			    end < drm_gpusvm_range_end(range)) {
> +				if (IS_DGFX(vm->xe) && xe_svm_range_in_vram(to_xe_range(range)))
> +					drm_gpusvm_range_evict(&vm->svm.gpusvm, range);
> +				__xe_svm_garbage_collector(vm, to_xe_range(range));
> +			}
> +		}
> +	}
> +}
> +
>  /**
>   * xe_svm_bo_evict() - SVM evict BO to system memory
>   * @bo: BO to evict
> diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
> index d5be8229ca7e..d00ba6d6ba53 100644
> --- a/drivers/gpu/drm/xe/xe_svm.h
> +++ b/drivers/gpu/drm/xe/xe_svm.h
> @@ -98,6 +98,8 @@ int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range,
>  bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vma *vma,
>  					u32 region);
>  
> +void xe_svm_range_clean_if_addr_within(struct xe_vm *vm, u64 start, u64 end);
> +
>  /**
>   * xe_svm_range_has_dma_mapping() - SVM range has DMA mapping
>   * @range: SVM range
> @@ -291,6 +293,11 @@ bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vm
>  	return false;
>  }
>  
> +static inline
> +void xe_svm_range_clean_if_addr_within(struct xe_vm *vm, u64 start, u64 end)
> +{
> +}
> +
>  #define xe_svm_assert_in_notifier(...) do {} while (0)
>  #define xe_svm_range_has_dma_mapping(...) false
>  
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index c7c012afe9eb..92b8e0cac063 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -2362,6 +2362,22 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct xe_vma_ops *vops,
>  			op->map.pat_index = pat_index;
>  			op->map.invalidate_on_bind =
>  				__xe_vm_needs_clear_scratch_pages(vm, flags);
> +		} else if (__op->op == DRM_GPUVA_OP_REMAP) {
> +			struct xe_vma *old =
> +				gpuva_to_vma(op->base.remap.unmap->va);
> +			u64 start = xe_vma_start(old), end = xe_vma_end(old);
> +
> +			if (op->base.remap.prev)
> +				start = op->base.remap.prev->va.addr +
> +					op->base.remap.prev->va.range;
> +			if (op->base.remap.next)
> +				end = op->base.remap.next->va.addr;
> +
> +			if (xe_vma_is_cpu_addr_mirror(old) &&
> +			    xe_svm_has_mapping(vm, start, end)) {
> +				drm_gpuva_ops_free(&vm->gpuvm, ops);
> +				return ERR_PTR(-EBUSY);
> +			}
>  		} else if (__op->op == DRM_GPUVA_OP_PREFETCH) {
>  			struct xe_vma *vma = gpuva_to_vma(op->base.prefetch.va);
>  
> @@ -2653,7 +2669,7 @@ static int vm_bind_ioctl_ops_parse(struct xe_vm *vm, struct drm_gpuva_ops *ops,
>  
>  			if (xe_vma_is_cpu_addr_mirror(old) &&
>  			    xe_svm_has_mapping(vm, start, end))
> -				return -EBUSY;
> +				xe_svm_range_clean_if_addr_within(vm, start, end);
>  
>  			op->remap.start = xe_vma_start(old);
>  			op->remap.range = xe_vma_size(old);
> -- 
> 2.34.1
>