Add support for virgl in GLPlatform

Summary:
This change adds detection support for virgl (Mesa gallium virtio guest driver).
Results in proper detection in supportInformation and debug console.

Test Plan: Modified test passes, run KWin_Wayland in kvm with virgl and verified supportInformation

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D25056

autotests/libkwineffects/data/glplatform/virgl-3.1

@@ -0,0 +1,22 @@
+[Driver]
+Vendor=Red Hat
+Renderer=virgl
+Version=3.1 Mesa 19.0.8
+ShadingLanguageVersion=1.40
+
+[Settings]
+LooseBinding=true
+GLSL=true
+TextureNPOT=true
+Mesa=true
+Gallium=true
+Virgl=true
+VirtualMachine=true
+GLVersion=3,1
+GLSLVersion=1,40
+MesaVersion=19,0,8
+GalliumVersion=0,4
+DriverVersion=19,0,8
+Driver=17
+ChipClass=99999
+Compositor=9

autotests/libkwineffects/kwinglplatformtest.cpp

@@ -78,6 +78,7 @@ void GLPlatformTest::testDriverToString_data()
     QTest::newRow("VirtualBox") << Driver_VirtualBox << QStringLiteral("VirtualBox (Chromium)");
     QTest::newRow("VMware") << Driver_VMware << QStringLiteral("VMware (SVGA3D)");
     QTest::newRow("Qualcomm") << Driver_Qualcomm << QStringLiteral("Qualcomm");
+    QTest::newRow("Virgl") << Driver_Virgl << QStringLiteral("Virgl (virtio-gpu, Qemu/KVM guest)");
     QTest::newRow("Unknown") << Driver_Unknown << QStringLiteral("Unknown");
 }
 
@@ -262,6 +263,7 @@ void GLPlatformTest::testDetect()
     QCOMPARE(gl->isVirtualBox(), settingsGroup.readEntry("VirtualBox", false));
     QCOMPARE(gl->isVMware(), settingsGroup.readEntry("VMware", false));
     QCOMPARE(gl->isAdreno(), settingsGroup.readEntry("Adreno", false));
+    QCOMPARE(gl->isVirgl(), settingsGroup.readEntry("Virgl", false));
 
     QCOMPARE(gl->isSoftwareEmulation(), settingsGroup.readEntry("SoftwareEmulation", false));
     QCOMPARE(gl->isVirtualMachine(), settingsGroup.readEntry("VirtualMachine", false));

libkwineffects/kwinglplatform.cpp

@@ -524,6 +524,8 @@ QByteArray GLPlatform::driverToString8(Driver driver)
         return QByteArrayLiteral("VMware (SVGA3D)");
     case Driver_Qualcomm:
         return QByteArrayLiteral("Qualcomm");
+    case Driver_Virgl:
+        return QByteArrayLiteral("Virgl (virtio-gpu, Qemu/KVM guest)");
 
     default:
         return QByteArrayLiteral("Unknown");
@@ -899,6 +901,11 @@ void GLPlatform::detect(OpenGLPlatformInterface platformInterface)
         else if (m_vendor == "VMware, Inc." && m_chipset.contains("SVGA3D")) {
             m_driver = Driver_VMware;
         }
+
+        // virgl
+        else if (m_renderer == "virgl") {
+            m_driver = Driver_Virgl;
+        }
     }
 
     // Driver/GPU specific features
@@ -1017,6 +1024,11 @@ void GLPlatform::detect(OpenGLPlatformInterface platformInterface)
         m_recommendedCompositor = OpenGL2Compositing;
     }
 
+    if (m_driver == Driver_Virgl) {
+        m_virtualMachine = true;
+        m_recommendedCompositor = OpenGL2Compositing;
+    }
+
     // and force back to shader supported on gles, we wouldn't have got a context if not supported
     if (isGLES()) {
         m_supportsGLSL = true;
@@ -1171,6 +1183,11 @@ bool GLPlatform::isVMware() const
     return m_driver == Driver_VMware;
 }
 
+bool GLPlatform::isVirgl() const
+{
+    return m_driver == Driver_Virgl;
+}
+
 bool GLPlatform::isSoftwareEmulation() const
 {
     return m_driver == Driver_Softpipe || m_driver == Driver_Swrast || m_driver == Driver_Llvmpipe;

libkwineffects/kwinglplatform.h

@@ -103,6 +103,7 @@ enum Driver {
     Driver_VMware,
     Driver_Qualcomm,
     Driver_RadeonSI,
+    Driver_Virgl,
     Driver_Unknown
 };
 
@@ -289,6 +290,12 @@ public:
      */
     bool isAdreno() const;
 
+    /**
+     * @returns @c true if the "GPU" is a virtio-gpu (Qemu/KVM)
+     * @since 5.18
+     **/
+    bool isVirgl() const;
+
     /**
      * @returns the GL_VERSION string as provided by the driver.
      * @since 4.9