qxl-wddm-dod: Prepare system thread for rendering

Create rendering thread upon device start and terminate it upon
stop. The dedicated thread is normally pending for display commands
to be sent to the host. Currently only single NULL (termination)
command is placed to the ring where the thread consumes events from.

Signed-off-by: Javier Celaya <javier.celaya@flexvdi.com>
Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Acked-by: Frediano Ziglio <fziglio@redhat.com>

qxldod/QxlDod.cpp

@@ -3062,6 +3062,7 @@ QxlDevice::QxlDevice(_In_ QxlDod* pQxlDod)
     m_CustomMode = 0;
     m_FreeOutputs = 0;
     m_Pending = 0;
+    m_PresentThread = NULL;
 }
 
 QxlDevice::~QxlDevice(void)
@@ -3441,6 +3442,25 @@ NTSTATUS QxlDevice::HWInit(PCM_RESOURCE_LIST pResList, DXGK_DISPLAY_INFORMATION*
     return QxlInit(pDispInfo);
 }
 
+NTSTATUS QxlDevice::StartPresentThread()
+{
+    PAGED_CODE();
+    OBJECT_ATTRIBUTES ObjectAttributes;
+    NTSTATUS Status;
+
+    InitializeObjectAttributes(&ObjectAttributes, NULL, OBJ_KERNEL_HANDLE, NULL, NULL);
+    Status = PsCreateSystemThread(
+        &m_PresentThread,
+        THREAD_ALL_ACCESS,
+        &ObjectAttributes,
+        NULL,
+        NULL,
+        PresentThreadRoutineWrapper,
+        this);
+
+    return Status;
+}
+
 NTSTATUS QxlDevice::QxlInit(DXGK_DISPLAY_INFORMATION* pDispInfo)
 {
     PAGED_CODE();
@@ -3467,12 +3487,17 @@ NTSTATUS QxlDevice::QxlInit(DXGK_DISPLAY_INFORMATION* pDispInfo)
     InitDeviceMemoryResources();
     InitMonitorConfig();
     Status = AcquireDisplayInfo(*(pDispInfo));
+    if (NT_SUCCESS(Status))
+    {
+        Status = StartPresentThread();
+    }
     return Status;
 }
 
 void QxlDevice::QxlClose()
 {
     PAGED_CODE();
+    StopPresentThread();
     DestroyMemSlots();
 }
 
@@ -3609,6 +3634,12 @@ BOOL QxlDevice::CreateEvents()
     KeInitializeEvent(&m_IoCmdEvent,
                       SynchronizationEvent,
                       FALSE);
+    KeInitializeEvent(&m_PresentEvent,
+                      SynchronizationEvent,
+                      FALSE);
+    KeInitializeEvent(&m_PresentThreadReadyEvent,
+                      SynchronizationEvent,
+                      FALSE);
     KeInitializeMutex(&m_MemLock,1);
     KeInitializeMutex(&m_CmdLock,1);
     KeInitializeMutex(&m_IoLock,1);
@@ -3625,6 +3656,7 @@ BOOL QxlDevice::CreateRings()
     m_CommandRing = &(m_RamHdr->cmd_ring);
     m_CursorRing = &(m_RamHdr->cursor_ring);
     m_ReleaseRing = &(m_RamHdr->release_ring);
+    SPICE_RING_INIT(m_PresentRing);
     DbgPrint(TRACE_LEVEL_VERBOSE, ("<--- %s\n", __FUNCTION__));
     return TRUE;
 }
@@ -4907,6 +4939,7 @@ UINT SpiceFromPixelFormat(D3DDDIFORMAT Format)
 
 NTSTATUS HwDeviceInterface::AcquireDisplayInfo(DXGK_DISPLAY_INFORMATION& DispInfo)
 {
+    PAGED_CODE();
     NTSTATUS Status = STATUS_SUCCESS;
     if (GetId() == 0)
     {
@@ -4996,3 +5029,78 @@ QXL_NON_PAGED VOID QxlDod::VsyncTimerProcGate(_In_ _KDPC *dpc, _In_ PVOID contex
     QxlDod* pQxl = reinterpret_cast<QxlDod*>(context);
     pQxl->VsyncTimerProc();
 }
+
+void QxlDevice::StopPresentThread()
+{
+    PAGED_CODE();
+    PVOID pDispatcherObject;
+    if (m_PresentThread)
+    {
+        DbgPrint(TRACE_LEVEL_INFORMATION, ("---> %s\n", __FUNCTION__));
+        PostToWorkerThread(NULL);
+        NTSTATUS Status = ObReferenceObjectByHandle(
+            m_PresentThread, 0, NULL, KernelMode, &pDispatcherObject, NULL);
+        if (NT_SUCCESS(Status))
+        {
+            WaitForObject(pDispatcherObject, NULL);
+            ObDereferenceObject(pDispatcherObject);
+        }
+        ZwClose(m_PresentThread);
+        m_PresentThread = NULL;
+        DbgPrint(TRACE_LEVEL_INFORMATION, ("<--- %s\n", __FUNCTION__));
+    }
+}
+
+void QxlDevice::PresentThreadRoutine()
+{
+    PAGED_CODE();
+    int wait;
+    int notify;
+    QXLDrawable** drawables;
+
+    DbgPrint(TRACE_LEVEL_INFORMATION, ("--->%s\n", __FUNCTION__));
+
+    while (1)
+    {
+        // Pop a drawables list from the ring
+        // No need for a mutex, only one consumer thread
+        SPICE_RING_CONS_WAIT(m_PresentRing, wait);
+        while (wait) {
+            WaitForObject(&m_PresentEvent, NULL);
+            SPICE_RING_CONS_WAIT(m_PresentRing, wait);
+        }
+        drawables = *SPICE_RING_CONS_ITEM(m_PresentRing);
+        SPICE_RING_POP(m_PresentRing, notify);
+        if (notify) {
+            KeSetEvent(&m_PresentThreadReadyEvent, 0, FALSE);
+        }
+
+        if (drawables) {
+            for (UINT i = 0; drawables[i]; ++i)
+                PushDrawable(drawables[i]);
+            delete[] drawables;
+        }
+        else {
+            DbgPrint(TRACE_LEVEL_WARNING, ("%s is being terminated\n", __FUNCTION__));
+            break;
+        }
+    }
+}
+
+void QxlDevice::PostToWorkerThread(QXLDrawable** drawables)
+{
+    PAGED_CODE();
+    // Push drawables into PresentRing and notify worker thread
+    int notify, wait;
+    SPICE_RING_PROD_WAIT(m_PresentRing, wait);
+    while (wait) {
+        WaitForObject(&m_PresentThreadReadyEvent, NULL);
+        SPICE_RING_PROD_WAIT(m_PresentRing, wait);
+    }
+    *SPICE_RING_PROD_ITEM(m_PresentRing) = drawables;
+    SPICE_RING_PUSH(m_PresentRing, notify);
+    if (notify) {
+        KeSetEvent(&m_PresentEvent, 0, FALSE);
+    }
+    DbgPrint(TRACE_LEVEL_INFORMATION, ("<--- %s\n", __FUNCTION__));
+}

qxldod/QxlDod.h

@@ -456,6 +456,10 @@ typedef struct DpcCbContext {
 #define MAX(x, y) (((x) >= (y)) ? (x) : (y))
 #define ALIGN(a, b) (((a) + ((b) - 1)) & ~((b) - 1))
 
+#include "start-packed.h"
+SPICE_RING_DECLARE(QXLPresentOnlyRing, QXLDrawable**, 1024);
+#include "end-packed.h"
+
 class QxlDevice  :
     public HwDeviceInterface
 {
@@ -559,6 +563,13 @@ private:
     NTSTATUS UpdateChildStatus(BOOLEAN connect);
     NTSTATUS SetCustomDisplay(QXLEscapeSetCustomDisplay* custom_display);
     void SetMonitorConfig(QXLHead* monitor_config);
+    NTSTATUS StartPresentThread();
+    void StopPresentThread();
+    void PresentThreadRoutine();
+    static void PresentThreadRoutineWrapper(HANDLE dev) {
+        ((QxlDevice *)dev)->PresentThreadRoutine();
+    }
+    void PostToWorkerThread(QXLDrawable** drawables);
 
     static LONG GetMaxSourceMappingHeight(RECT* DirtyRects, ULONG NumDirtyRects);
 
@@ -594,6 +605,8 @@ private:
     KEVENT m_DisplayEvent;
     KEVENT m_CursorEvent;
     KEVENT m_IoCmdEvent;
+    KEVENT m_PresentEvent;
+    KEVENT m_PresentThreadReadyEvent;
 
     PUCHAR m_LogPort;
     PUCHAR m_LogBuf;
@@ -609,6 +622,9 @@ private:
 
     QXLMonitorsConfig* m_monitor_config;
     QXLPHYSICAL* m_monitor_config_pa;
+
+    QXLPresentOnlyRing m_PresentRing[1];
+    HANDLE m_PresentThread;
 };
 
 class QxlDod {