[PATCH v4 17/33] drm/xe: Do not allow CPU address mirror VMA unbind if the GPU has bindings

[Matthew Brost <matthew.brost@intel.com>]

uAPI is designed with the use case that only mapping a BO to a malloc'd
address will unbind a CPU-address mirror VMA. Therefore, allowing a
CPU-address mirror VMA to unbind when the GPU has bindings in the range
being unbound does not make much sense. This behavior is not supported,
as it simplifies the code. This decision can always be revisited if a
use case arises.

v3:
 - s/arrises/arises (Thomas)
 - s/system allocator/GPU address mirror (Thomas)
 - Kernel doc (Thomas)
 - Newline between function defs (Thomas)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_svm.c |  5 +++++
 drivers/gpu/drm/xe/xe_svm.h |  2 ++
 drivers/gpu/drm/xe/xe_vm.c  | 16 ++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index 03c5cbcacb0e..56ece53b2069 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -428,3 +428,8 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 
 	return err;
 }
+
+bool xe_svm_has_mapping(struct xe_vm *vm, u64 start, u64 end)
+{
+	return drm_gpusvm_has_mapping(&vm->svm.gpusvm, start, end);
+}
diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
index ef5bc4e919e8..b181c174ca61 100644
--- a/drivers/gpu/drm/xe/xe_svm.h
+++ b/drivers/gpu/drm/xe/xe_svm.h
@@ -46,6 +46,8 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 			    struct xe_tile *tile, u64 fault_addr,
 			    bool atomic);
 
+bool xe_svm_has_mapping(struct xe_vm *vm, u64 start, u64 end);
+
 static inline bool xe_svm_range_pages_valid(struct xe_svm_range *range)
 {
 	return drm_gpusvm_range_pages_valid(range->base.gpusvm, &range->base);
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 6fa446884955..d8c78ecd54ec 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2398,6 +2398,17 @@ static int vm_bind_ioctl_ops_parse(struct xe_vm *vm, struct drm_gpuva_ops *ops,
 			struct xe_vma *old =
 				gpuva_to_vma(op->base.remap.unmap->va);
 			bool skip = xe_vma_is_cpu_addr_mirror(old);
+			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))
+				return -EBUSY;
 
 			op->remap.start = xe_vma_start(old);
 			op->remap.range = xe_vma_size(old);
@@ -2480,6 +2491,11 @@ static int vm_bind_ioctl_ops_parse(struct xe_vm *vm, struct drm_gpuva_ops *ops,
 		{
 			struct xe_vma *vma = gpuva_to_vma(op->base.unmap.va);
 
+			if (xe_vma_is_cpu_addr_mirror(vma) &&
+			    xe_svm_has_mapping(vm, xe_vma_start(vma),
+					       xe_vma_end(vma)))
+				return -EBUSY;
+
 			if (!xe_vma_is_cpu_addr_mirror(vma))
 				xe_vma_ops_incr_pt_update_ops(vops, op->tile_mask);
 			break;
-- 
2.34.1