Mesa (main): radv: Require an alignment of 64 for accel structs

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Module: Mesa
Branch: main
Commit: e8da8fc5b7429e3aa832e1153f900765951470d4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=e8da8fc5b7429e3aa832e1153f900765951470d4

Author: Konstantin Seurer <konstantin.seurer at gmail.com>
Date:   Sat Jun  4 20:50:49 2022 +0200

radv: Require an alignment of 64 for accel structs

Top level acceleration structures need the bottom
6 bits to store the root ids of instances. If we
don't require that alignment, more "advanced"
allocators like VMA may sub allocate a buffer
which can lead to the 6 getting lost.

Fixes the Khronos ray tracing Vulkan samples.

Closes: #6598
Signed-off-by: Konstantin Seurer <konstantin.seurer at gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16870>

---

 src/amd/vulkan/radv_device.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/amd/vulkan/radv_device.c b/src/amd/vulkan/radv_device.c
index 830516c157d..752683075f5 100644
--- a/src/amd/vulkan/radv_device.c
+++ b/src/amd/vulkan/radv_device.c
@@ -5043,9 +5043,8 @@ radv_InvalidateMappedMemoryRanges(VkDevice _device, uint32_t memoryRangeCount,
 }
 
 static void
-radv_get_buffer_memory_requirements(struct radv_device *device,
-                                    VkDeviceSize size,
-                                    VkBufferCreateFlags flags,
+radv_get_buffer_memory_requirements(struct radv_device *device, VkDeviceSize size,
+                                    VkBufferCreateFlags flags, VkBufferCreateFlags usage,
                                     VkMemoryRequirements2 *pMemoryRequirements)
 {
    pMemoryRequirements->memoryRequirements.memoryTypeBits =
@@ -5056,6 +5055,14 @@ radv_get_buffer_memory_requirements(struct radv_device *device,
    else
       pMemoryRequirements->memoryRequirements.alignment = 16;
 
+   /* Top level acceleration structures need the bottom 6 bits to store
+    * the root ids of instances. The hardware also needs bvh nodes to
+    * be 64 byte aligned.
+    */
+   if (usage & VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_STORAGE_BIT_KHR)
+      pMemoryRequirements->memoryRequirements.alignment =
+         MAX2(pMemoryRequirements->memoryRequirements.alignment, 64);
+
    pMemoryRequirements->memoryRequirements.size =
       align64(size, pMemoryRequirements->memoryRequirements.alignment);
 
@@ -5082,7 +5089,7 @@ radv_GetBufferMemoryRequirements2(VkDevice _device, const VkBufferMemoryRequirem
    RADV_FROM_HANDLE(radv_buffer, buffer, pInfo->buffer);
 
    radv_get_buffer_memory_requirements(device, buffer->vk.size, buffer->vk.create_flags,
-                                       pMemoryRequirements);
+                                       buffer->vk.usage, pMemoryRequirements);
 }
 
 VKAPI_ATTR void VKAPI_CALL
@@ -5093,7 +5100,7 @@ radv_GetDeviceBufferMemoryRequirements(VkDevice _device,
    RADV_FROM_HANDLE(radv_device, device, _device);
 
    radv_get_buffer_memory_requirements(device, pInfo->pCreateInfo->size, pInfo->pCreateInfo->flags,
-                                       pMemoryRequirements);
+                                       pInfo->pCreateInfo->usage, pMemoryRequirements);
 }
 
 VKAPI_ATTR void VKAPI_CALL