3 files changed, 200 insertions, 1 deletions

diff --git a/src/video_core/CMakeLists.txt b/src/video_core/CMakeLists.txt
index 6036d6ed3..60529323e 100644
--- a/src/video_core/CMakeLists.txt
+++ b/src/video_core/CMakeLists.txt
@@ -111,7 +111,9 @@ if (ENABLE_VULKAN)
         renderer_vulkan/vk_resource_manager.cpp
         renderer_vulkan/vk_resource_manager.h
         renderer_vulkan/vk_scheduler.cpp
-        renderer_vulkan/vk_scheduler.h)
+        renderer_vulkan/vk_scheduler.h
+        renderer_vulkan/vk_stream_buffer.cpp
+        renderer_vulkan/vk_stream_buffer.h)
 
     target_include_directories(video_core PRIVATE ../../externals/Vulkan-Headers/include)
     target_compile_definitions(video_core PRIVATE HAS_VULKAN)
diff --git a/src/video_core/renderer_vulkan/vk_stream_buffer.cpp b/src/video_core/renderer_vulkan/vk_stream_buffer.cpp
new file mode 100644
index 000000000..1c5aefaec
--- /dev/null
+++ b/src/video_core/renderer_vulkan/vk_stream_buffer.cpp
@@ -0,0 +1,124 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <memory>
+#include <optional>
+#include <vector>
+
+#include "common/assert.h"
+#include "video_core/renderer_vulkan/declarations.h"
+#include "video_core/renderer_vulkan/vk_device.h"
+#include "video_core/renderer_vulkan/vk_memory_manager.h"
+#include "video_core/renderer_vulkan/vk_resource_manager.h"
+#include "video_core/renderer_vulkan/vk_scheduler.h"
+#include "video_core/renderer_vulkan/vk_stream_buffer.h"
+
+namespace Vulkan {
+
+constexpr u64 WATCHES_INITIAL_RESERVE = 0x4000;
+constexpr u64 WATCHES_RESERVE_CHUNK = 0x1000;
+
+VKStreamBuffer::VKStreamBuffer(const VKDevice& device, VKMemoryManager& memory_manager,
+                               VKScheduler& scheduler, u64 size, vk::BufferUsageFlags usage,
+                               vk::AccessFlags access, vk::PipelineStageFlags pipeline_stage)
+    : device{device}, scheduler{scheduler},
+      has_device_exclusive_memory{!memory_manager.IsMemoryUnified()},
+      buffer_size{size}, access{access}, pipeline_stage{pipeline_stage} {
+    CreateBuffers(memory_manager, usage);
+    ReserveWatches(WATCHES_INITIAL_RESERVE);
+}
+
+VKStreamBuffer::~VKStreamBuffer() = default;
+
+std::tuple<u8*, u64, vk::Buffer, bool> VKStreamBuffer::Reserve(u64 size, bool keep_in_host) {
+    ASSERT(size <= buffer_size);
+    mapped_size = size;
+
+    if (offset + size > buffer_size) {
+        // The buffer would overflow, save the amount of used buffers, signal an invalidation and
+        // reset the state.
+        invalidation_mark = used_watches;
+        used_watches = 0;
+        offset = 0;
+    }
+
+    use_device = has_device_exclusive_memory && !keep_in_host;
+
+    const vk::Buffer buffer = use_device ? *device_buffer : *mappable_buffer;
+    return {mapped_pointer + offset, offset, buffer, invalidation_mark.has_value()};
+}
+
+VKExecutionContext VKStreamBuffer::Send(VKExecutionContext exctx, u64 size) {
+    ASSERT_MSG(size <= mapped_size, "Reserved size is too small");
+
+    if (invalidation_mark) {
+        // TODO(Rodrigo): Find a better way to invalidate than waiting for all watches to finish.
+        exctx = scheduler.Flush();
+        std::for_each(watches.begin(), watches.begin() + *invalidation_mark,
+                      [&](auto& resource) { resource->Wait(); });
+        invalidation_mark = std::nullopt;
+    }
+
+    // Only copy to VRAM when requested.
+    if (use_device) {
+        const auto& dld = device.GetDispatchLoader();
+        const u32 graphics_family = device.GetGraphicsFamily();
+        const auto cmdbuf = exctx.GetCommandBuffer();
+
+        // Buffers are mirrored, that's why the copy is done with the same offset on both buffers.
+        const vk::BufferCopy copy_region(offset, offset, size);
+        cmdbuf.copyBuffer(*mappable_buffer, *device_buffer, {copy_region}, dld);
+
+        // Protect the buffer from GPU usage until the copy has finished.
+        const vk::BufferMemoryBarrier barrier(vk::AccessFlagBits::eTransferWrite, access,
+                                              graphics_family, graphics_family, *device_buffer,
+                                              offset, size);
+        cmdbuf.pipelineBarrier(vk::PipelineStageFlagBits::eTransfer, pipeline_stage, {}, {},
+                               {barrier}, {}, dld);
+    }
+
+    if (used_watches + 1 >= watches.size()) {
+        // Ensure that there are enough watches.
+        ReserveWatches(WATCHES_RESERVE_CHUNK);
+    }
+    // Add a watch for this allocation.
+    watches[used_watches++]->Watch(exctx.GetFence());
+
+    offset += size;
+
+    return exctx;
+}
+
+void VKStreamBuffer::CreateBuffers(VKMemoryManager& memory_manager, vk::BufferUsageFlags usage) {
+    vk::BufferUsageFlags mappable_usage = usage;
+    if (has_device_exclusive_memory) {
+        mappable_usage |= vk::BufferUsageFlagBits::eTransferSrc;
+    }
+    const vk::BufferCreateInfo buffer_ci({}, buffer_size, mappable_usage,
+                                         vk::SharingMode::eExclusive, 0, nullptr);
+
+    const auto dev = device.GetLogical();
+    const auto& dld = device.GetDispatchLoader();
+    mappable_buffer = dev.createBufferUnique(buffer_ci, nullptr, dld);
+    mappable_commit = memory_manager.Commit(*mappable_buffer, true);
+    mapped_pointer = mappable_commit->GetData();
+
+    if (has_device_exclusive_memory) {
+        const vk::BufferCreateInfo buffer_ci({}, buffer_size,
+                                             usage | vk::BufferUsageFlagBits::eTransferDst,
+                                             vk::SharingMode::eExclusive, 0, nullptr);
+        device_buffer = dev.createBufferUnique(buffer_ci, nullptr, dld);
+        device_commit = memory_manager.Commit(*device_buffer, false);
+    }
+}
+
+void VKStreamBuffer::ReserveWatches(std::size_t grow_size) {
+    const std::size_t previous_size = watches.size();
+    watches.resize(previous_size + grow_size);
+    std::generate(watches.begin() + previous_size, watches.end(),
+                  []() { return std::make_unique<VKFenceWatch>(); });
+}
+
+} // namespace Vulkan
diff --git a/src/video_core/renderer_vulkan/vk_stream_buffer.h b/src/video_core/renderer_vulkan/vk_stream_buffer.h
new file mode 100644
index 000000000..8c00d383a
--- /dev/null
+++ b/src/video_core/renderer_vulkan/vk_stream_buffer.h
@@ -0,0 +1,73 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <optional>
+#include <tuple>
+#include <vector>
+
+#include "common/common_types.h"
+#include "video_core/renderer_vulkan/declarations.h"
+#include "video_core/renderer_vulkan/vk_memory_manager.h"
+
+namespace Vulkan {
+
+class VKDevice;
+class VKFence;
+class VKFenceWatch;
+class VKResourceManager;
+class VKScheduler;
+
+class VKStreamBuffer {
+public:
+    explicit VKStreamBuffer(const VKDevice& device, VKMemoryManager& memory_manager,
+                            VKScheduler& scheduler, u64 size, vk::BufferUsageFlags usage,
+                            vk::AccessFlags access, vk::PipelineStageFlags pipeline_stage);
+    ~VKStreamBuffer();
+
+    /**
+     * Reserves a region of memory from the stream buffer.
+     * @param size Size to reserve.
+     * @param keep_in_host Mapped buffer will be in host memory, skipping the copy to device local.
+     * @returns A tuple in the following order: Raw memory pointer (with offset added), buffer
+     * offset, Vulkan buffer handle, buffer has been invalited.
+     */
+    std::tuple<u8*, u64, vk::Buffer, bool> Reserve(u64 size, bool keep_in_host);
+
+    /// Ensures that "size" bytes of memory are available to the GPU, potentially recording a copy.
+    [[nodiscard]] VKExecutionContext Send(VKExecutionContext exctx, u64 size);
+
+private:
+    /// Creates Vulkan buffer handles committing the required the required memory.
+    void CreateBuffers(VKMemoryManager& memory_manager, vk::BufferUsageFlags usage);
+
+    /// Increases the amount of watches available.
+    void ReserveWatches(std::size_t grow_size);
+
+    const VKDevice& device;                      ///< Vulkan device manager.
+    VKScheduler& scheduler;                      ///< Command scheduler.
+    const u64 buffer_size;                       ///< Total size of the stream buffer.
+    const bool has_device_exclusive_memory;      ///< True if the streaming buffer will use VRAM.
+    const vk::AccessFlags access;                ///< Access usage of this stream buffer.
+    const vk::PipelineStageFlags pipeline_stage; ///< Pipeline usage of this stream buffer.
+
+    UniqueBuffer mappable_buffer;   ///< Mapped buffer.
+    UniqueBuffer device_buffer;     ///< Buffer exclusive to the GPU.
+    VKMemoryCommit mappable_commit; ///< Commit visible from the CPU.
+    VKMemoryCommit device_commit;   ///< Commit stored in VRAM.
+    u8* mapped_pointer{};           ///< Pointer to the host visible commit
+
+    u64 offset{};      ///< Buffer iterator.
+    u64 mapped_size{}; ///< Size reserved for the current copy.
+    bool use_device{}; ///< True if the current uses VRAM.
+
+    std::vector<std::unique_ptr<VKFenceWatch>> watches; ///< Total watches
+    std::size_t used_watches{}; ///< Count of watches, reset on invalidation.
+    std::optional<std::size_t>
+        invalidation_mark{}; ///< Number of watches used in the current invalidation.
+};
+
+} // namespace Vulkan