feat: 가상화 문서들 추가

2026-09-10 08:54:05 +09:00
parent e9f6a93327
commit 43e1aadef0
695 changed files with 153404 additions and 12754 deletions
@@ -0,0 +1,32 @@
+# 게스트의 write() 가 virtqueue 에 실리기까지
+
+## Alternative text
+
+게스트 사용자 공간의 PostgreSQL/Keycloak 에서 시작한 write() 가 게스트 커널의 VFS, ext4/XFS, Guest Page Cache, Guest Block Layer, /dev/vda, virtio-blk Frontend 를 거쳐 virtqueue 에 도달하는 위에서 아래로 읽는 흐름도.
+
+## Long description
+
+위에서 아래로 읽는다. 맨 위 Guest Userspace 구역에 PostgreSQL / Keycloak 이 있고 write() 가 게스트 커널로 내려간다. Guest Kernel 구역 안에서 VFS 가 먼저 받고, ext4 / XFS 가 파일을 block 공간에 배치하고, Guest Page Cache 가 그 내용을 dirty page 로 받아 두었다가 writeback 으로 Guest Block Layer 에 내려보낸다. Guest Block Layer 는 그것을 WRITE 나 FLUSH 요청으로 바꿔 /dev/vda 에 걸고, virtio-blk Frontend 가 그 요청을 virtqueue 에 게시한다. virtqueue 아래의 VM Boundary 부터는 QEMU 와 호스트 계층이라 이 그림에서 잘랐다. 완료가 같은 virtqueue 로 되돌아오는 역방향은 SSOT 의 다른 절이 대는 사실이라 이 그림에 넣지 않았고 본문 문단이 맡는다.
+
+## Elements and evidence
+
+- **Boundary: Guest Userspace** (boundary): 게스트 사용자 공간. 저장장치를 직접 다루지 않는다. Evidence: L5807–L5809.
+- **Boundary: Guest Kernel** (boundary): 게스트 커널 공간. VM Boundary 위쪽 계층이 전부 여기 있다. Evidence: L5815–L5833.
+- **PostgreSQL / Keycloak** (service): 파일 연산을 요청하는 게스트 프로세스. Evidence: L5807–L5809, L5885–L5885, L5811–L5813.
+- **VFS** (service): 열린 파일이 어느 filesystem 구현에 속하는지 보고 연산을 넘기는 공통 계층. Evidence: L5815–L5817, L5905–L5905.
+- **ext4 / XFS** (service): 파일과 디렉터리를 block 공간에 배치하는 게스트 filesystem. Evidence: L5819–L5819.
+- **Guest Page Cache** (store): 게스트 RAM 에 있는 cache. write() 가 성공해도 데이터는 아직 여기까지만 확정된다. Evidence: L5821–L5821.
+- **Guest Block Layer** (service): 파일 세계의 요청을 block device 세계의 요청으로 바꾸는 계층. Evidence: L5825–L5825.
+- **/dev/vda** (device): 게스트 Linux 가 하나의 block device 로 인식하는 이름. Evidence: L5829–L5829, L5879–L5879.
+- **virtio-blk Frontend** (service): 그 가상 block device 를 제어하는 게스트 커널 driver. Evidence: L5831–L5831, L5789–L5789.
+- **virtqueue** (queue): 요청이 실리는 자리. 바로 아래가 VM Boundary 다. Evidence: L5833–L5835.
+
+## Relationships
+
+- **PostgreSQL / Keycloak → VFS:** data. Evidence: L5811–L5813, L5890–L5890.
+- **VFS → ext4 / XFS:** data. Evidence: L5817–L5819.
+- **ext4 / XFS → Guest Page Cache:** data. Evidence: L5819–L5821.
+- **Guest Page Cache → Guest Block Layer:** writeback. Evidence: L5823–L5825.
+- **Guest Block Layer → /dev/vda:** WRITE / FLUSH. Evidence: L5827–L5829.
+- **/dev/vda → virtio-blk Frontend:** data. Evidence: L5829–L5831.
+- **virtio-blk Frontend → virtqueue:** Virtio block request. Evidence: L5831–L5833.
@@ -0,0 +1,38 @@
+# 게스트의 write() 가 virtqueue 에 실리기까지
+# Question: 게스트 애플리케이션의 write() 는 virtqueue 에 실리기 전에 게스트의 어느 계층을 어떤 순서로 지나는가
+direction: down
+g0: "Guest Userspace" {
+  n0: "PostgreSQL / Keycloak" {
+    shape: rectangle
+  }
+}
+g1: "Guest Kernel" {
+  n1: "VFS" {
+    shape: rectangle
+  }
+  n2: "ext4 / XFS" {
+    shape: rectangle
+  }
+  n3: "Guest Page Cache" {
+    shape: rectangle
+  }
+  n4: "Guest Block Layer" {
+    shape: rectangle
+  }
+  n5: "/dev/vda" {
+    shape: rectangle
+  }
+  n6: "virtio-blk Frontend" {
+    shape: rectangle
+  }
+  n7: "virtqueue" {
+    shape: queue
+  }
+}
+g0.n0 -> g1.n1
+g1.n1 -> g1.n2
+g1.n2 -> g1.n3
+g1.n3 -> g1.n4: "writeback"
+g1.n4 -> g1.n5: "WRITE / FLUSH"
+g1.n5 -> g1.n6
+g1.n6 -> g1.n7: "Virtio block request"
@@ -0,0 +1,76 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<mxfile host="app.diagrams.net" modified="2026-07-23T00:00:00.000Z" agent="techviz-harness" version="24.7.17" type="device">
+  <diagram id="guest-block-io-to-virtqueue" name="게스트의 write() 가 virtqueue 에 실리기까지">
+    <mxGraphModel dx="680" dy="1360" grid="1" gridSize="10" guides="1" tooltips="1" connect="1" arrows="1" fold="1" page="1" pageScale="1" pageWidth="827" pageHeight="1360" math="0" shadow="0">
+      <root>
+        <mxCell id="0"/>
+        <mxCell id="1" parent="0"/>
+        <mxCell id="g_guest-userspace" value="Guest Userspace" style="swimlane;html=1;rounded=1;startSize=30;horizontal=1;dashed=1;strokeWidth=1.5;fillColor=#f7f9fb;strokeColor=#66788a;fontStyle=1;fontSize=13;" vertex="1" parent="1">
+          <mxGeometry x="40.0" y="35.0" width="241.0" height="160.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="g_guest-kernel" value="Guest Kernel" style="swimlane;html=1;rounded=1;startSize=30;horizontal=1;dashed=1;strokeWidth=1.5;fillColor=#f7f9fb;strokeColor=#66788a;fontStyle=1;fontSize=13;" vertex="1" parent="1">
+          <mxGeometry x="47.0" y="219.0" width="227.0" height="1096.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_app" value="PostgreSQL / Keycloak&lt;br/&gt;read / write&lt;br/&gt;fsync / sync" tooltip="파일 연산을 요청하는 게스트 프로세스. | Evidence: L5807-L5809, L5885-L5885, L5811-L5813" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="70.0" y="81.0" width="181.0" height="88.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_vfs" value="VFS" tooltip="열린 파일이 어느 filesystem 구현에 속하는지 보고 연산을 넘기는 공통 계층. | Evidence: L5815-L5817, L5905-L5905" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="85.5" y="265.0" width="150.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_fs" value="ext4 / XFS" tooltip="파일과 디렉터리를 block 공간에 배치하는 게스트 filesystem. | Evidence: L5819-L5819" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="85.5" y="425.0" width="150.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_page-cache" value="Guest Page Cache" tooltip="게스트 RAM 에 있는 cache. write() 가 성공해도 데이터는 아직 여기까지만 확정된다. | Evidence: L5821-L5821" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="85.5" y="585.0" width="150.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_block-layer" value="Guest Block Layer" tooltip="파일 세계의 요청을 block device 세계의 요청으로 바꾸는 계층. | Evidence: L5825-L5825" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="84.0" y="745.0" width="153.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_vda" value="/dev/vda" tooltip="게스트 Linux 가 하나의 block device 로 인식하는 이름. | Evidence: L5829-L5829, L5879-L5879" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="85.5" y="905.0" width="150.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_virtio-blk" value="virtio-blk Frontend" tooltip="그 가상 block device 를 제어하는 게스트 커널 driver. | Evidence: L5831-L5831, L5789-L5789" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;" vertex="1" parent="1">
+          <mxGeometry x="77.0" y="1065.0" width="167.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="n_virtqueue" value="virtqueue" tooltip="요청이 실리는 자리. 바로 아래가 VM Boundary 다. | Evidence: L5833-L5835" style="whiteSpace=wrap;html=1;rounded=1;strokeWidth=2;fontSize=14;fontStyle=1;fillColor=#ffffff;strokeColor=#2d4357;verticalAlign=middle;strokeColor=#2563eb;strokeWidth=2;" vertex="1" parent="1">
+          <mxGeometry x="85.5" y="1225.0" width="150.0" height="64.0" as="geometry"/>
+        </mxCell>
+        <mxCell id="e_app-to-vfs" value="" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_app" target="n_vfs">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="217.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+        <mxCell id="e_vfs-to-fs" value="" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_vfs" target="n_fs">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="377.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+        <mxCell id="e_fs-to-page-cache" value="" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_fs" target="n_page-cache">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="537.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+        <mxCell id="e_page-cache-to-block-layer" value="writeback" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_page-cache" target="n_block-layer">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="697.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+        <mxCell id="e_block-layer-to-vda" value="WRITE / FLUSH" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_block-layer" target="n_vda">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="857.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+        <mxCell id="e_vda-to-virtio-blk" value="" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_vda" target="n_virtio-blk">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="1017.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+        <mxCell id="e_virtio-blk-to-virtqueue" value="Virtio block request" style="edgeStyle=orthogonalEdgeStyle;rounded=0;orthogonalLoop=1;jettySize=auto;html=1;strokeWidth=2;endArrow=block;endFill=1;" edge="1" parent="1" source="n_virtio-blk" target="n_virtqueue">
+          <mxGeometry relative="1" as="geometry">
+            <mxPoint x="184.5" y="1177.0" as="offset"/>
+          </mxGeometry>
+        </mxCell>
+      </root>
+    </mxGraphModel>
+  </diagram>
+</mxfile>
@@ -0,0 +1,31 @@
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+    "anchor": {
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+      "value": "128. 전체 구조",
+      "line": 5804
+    }
+  },
+  "outputs": [
+    "guest-block-io-to-virtqueue.svg",
+    "guest-block-io-to-virtqueue.drawio",
+    "guest-block-io-to-virtqueue.mmd",
+    "guest-block-io-to-virtqueue.d2",
+    "guest-block-io-to-virtqueue.excalidraw",
+    "guest-block-io-to-virtqueue.alt.md"
+  ],
+  "lint_issue_count": 5,
+  "assumption_count": 0,
+  "assumptions_allowed": false,
+  "composition_profile": "component-flow",
+  "reference_ids": [
+    "payment-event-flow"
+  ],
+  "diagram_only": true
+}
@@ -0,0 +1,22 @@
+%% 게스트의 write() 가 virtqueue 에 실리기까지
+%% question: 게스트 애플리케이션의 write() 는 virtqueue 에 실리기 전에 게스트의 어느 계층을 어떤 순서로 지나는가
+flowchart TB
+    subgraph g_guest_userspace["Guest Userspace"]
+        n0["PostgreSQL / Keycloak"]
+    end
+    subgraph g_guest_kernel["Guest Kernel"]
+        n1["VFS"]
+        n2["ext4 / XFS"]
+        n3["Guest Page Cache"]
+        n4["Guest Block Layer"]
+        n5["/dev/vda"]
+        n6["virtio-blk Frontend"]
+        n7(["virtqueue"])
+    end
+    n0 --> n1
+    n1 --> n2
+    n2 --> n3
+    n3 -->|"writeback"| n4
+    n4 -->|"WRITE / FLUSH"| n5
+    n5 --> n6
+    n6 -->|"Virtio block request"| n7
@@ -0,0 +1,107 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="680" height="1360" viewBox="0 0 680 1360" role="img" aria-labelledby="diagram-title diagram-description">
+<title id="diagram-title">게스트의 write() 가 virtqueue 에 실리기까지</title>
+<desc id="diagram-description">위에서 아래로 읽는다. 맨 위 Guest Userspace 구역에 PostgreSQL / Keycloak 이 있고 write() 가 게스트 커널로 내려간다. Guest Kernel 구역 안에서 VFS 가 먼저 받고, ext4 / XFS 가 파일을 block 공간에 배치하고, Guest Page Cache 가 그 내용을 dirty page 로 받아 두었다가 writeback 으로 Guest Block Layer 에 내려보낸다. Guest Block Layer 는 그것을 WRITE 나 FLUSH 요청으로 바꿔 /dev/vda 에 걸고, virtio-blk Frontend 가 그 요청을 virtqueue 에 게시한다. virtqueue 아래의 VM Boundary 부터는 QEMU 와 호스트 계층이라 이 그림에서 잘랐다. 완료가 같은 virtqueue 로 되돌아오는 역방향은 SSOT 의 다른 절이 대는 사실이라 이 그림에 넣지 않았고 본문 문단이 맡는다.</desc>
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