[PATCH v5 07/11] drm/gpuvm: Ensure correctness of unmap/remaps of repeated regions

[Adrián Larumbe <adrian.larumbe@collabora.com>]

When an unmap or map operation that leads to a remap intersects with a
GPU VA that spans over a repeated range, the newly spawned VAs must
preserve the repeated property, ie, VA's range must be a multiple of
gem.range, and also the VA's start address must be on a gem.range
boundary. When this doesn't hold, disallow such operations and notify
UM with an invalid argument error.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
---
 drivers/gpu/drm/drm_gpuvm.c | 67 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_gpuvm.h     |  7 +++-
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c
index ca7445f767fc..80750119221d 100644
--- a/drivers/gpu/drm/drm_gpuvm.c
+++ b/drivers/gpu/drm/drm_gpuvm.c
@@ -2462,6 +2462,65 @@ static int validate_map_request(struct drm_gpuvm *gpuvm,
 	return 0;
 }
 
+static int
+validate_repeated_unmap_request(struct drm_gpuvm *gpuvm,
+				u64 req_addr, u64 req_end)
+{
+	struct drm_gpuva *first, *last, *va;
+	u64 multiple;
+
+	if (!(gpuvm->flags & DRM_GPUVM_HAS_REPEAT_MAPS))
+		return 0;
+
+	/* Find the first and last VAs the map request intersects with */
+	first = last = NULL;
+	drm_gpuvm_for_each_va_range(va, gpuvm, req_addr, req_end) {
+		if (!first)
+			first = va;
+		last = va;
+	}
+
+	if (!first)
+		return 0;
+
+	if (first->flags & DRM_GPUVA_REPEAT) {
+		u64 addr = first->va.addr;
+		u64 range = first->va.range;
+		u64 end = addr + range;
+
+		drm_WARN_ON(gpuvm->drm, first->gem.repeat_range == 0);
+
+		if (addr < req_addr) {
+			multiple = req_addr;
+			if (do_div(multiple, first->gem.repeat_range))
+				return -EINVAL;
+		}
+
+		if (end > req_end) {
+			multiple = req_end;
+			if (do_div(multiple, first->gem.repeat_range))
+				return -EINVAL;
+			return 0;
+		}
+	}
+
+	if ((first != last) && (last->flags & DRM_GPUVA_REPEAT)) {
+		u64 addr = last->va.addr;
+		u64 range = last->va.range;
+		u64 end = addr + range;
+
+		drm_WARN_ON(last->vm->drm, last->gem.repeat_range == 0);
+
+		if (end > req_end) {
+			multiple = req_end;
+			if (do_div(multiple, last->gem.repeat_range))
+				return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static int
 __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
 		   const struct drm_gpuvm_ops *ops, void *priv,
@@ -2479,6 +2538,10 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
 	if (unlikely(ret))
 		return -EINVAL;
 
+	ret = validate_repeated_unmap_request(gpuvm, req_addr, req_end);
+	if (ret)
+		return ret;
+
 	drm_gpuvm_for_each_va_range_safe(va, next, gpuvm, req_addr, req_end) {
 		struct drm_gem_object *obj = va->gem.obj;
 		u64 offset = va->gem.offset;
@@ -2653,6 +2716,10 @@ __drm_gpuvm_sm_unmap(struct drm_gpuvm *gpuvm,
 	if (unlikely(!drm_gpuvm_range_valid(gpuvm, req_addr, req_range)))
 		return -EINVAL;
 
+	ret = validate_repeated_unmap_request(gpuvm, req_addr, req_end);
+	if (ret)
+		return ret;
+
 	drm_gpuvm_for_each_va_range_safe(va, next, gpuvm, req_addr, req_end) {
 		struct drm_gpuva_op_map prev = {}, next = {};
 		bool prev_split = false, next_split = false;
diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h
index cd2f55bc1707..61f66dfe4ed7 100644
--- a/include/drm/drm_gpuvm.h
+++ b/include/drm/drm_gpuvm.h
@@ -230,10 +230,15 @@ enum drm_gpuvm_flags {
 	 */
 	DRM_GPUVM_IMMEDIATE_MODE = BIT(1),
 
+	/**
+	 * @DRM_GPUVM_HAS_REPEAT_MAPS: There are repeated VAs in the GPUVM
+	 */
+	DRM_GPUVM_HAS_REPEAT_MAPS = BIT(2),
+
 	/**
 	 * @DRM_GPUVM_USERBITS: user defined bits
 	 */
-	DRM_GPUVM_USERBITS = BIT(2),
+	DRM_GPUVM_USERBITS = BIT(3),
 };
 
 /**
-- 
2.53.0