1 files changed, 465 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/misc/reqqueue.cpp b/src/VBox/Runtime/common/misc/reqqueue.cpp
new file mode 100644
index 00000000..c0c89e1a
--- /dev/null
+++ b/src/VBox/Runtime/common/misc/reqqueue.cpp
@@ -0,0 +1,465 @@
+/* $Id: reqqueue.cpp $ */
+/** @file
+ * IPRT - Request Queue.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/req.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/asm.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#include <iprt/semaphore.h>
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+
+#include "internal/req.h"
+#include "internal/magics.h"
+
+
+
+RTDECL(int) RTReqQueueCreate(RTREQQUEUE *phQueue)
+{
+    PRTREQQUEUEINT pQueue = (PRTREQQUEUEINT)RTMemAllocZ(sizeof(RTREQQUEUEINT));
+    if (!pQueue)
+        return VERR_NO_MEMORY;
+    int rc = RTSemEventCreate(&pQueue->EventSem);
+    if (RT_SUCCESS(rc))
+    {
+        pQueue->u32Magic = RTREQQUEUE_MAGIC;
+
+        *phQueue = pQueue;
+        return VINF_SUCCESS;
+    }
+
+    RTMemFree(pQueue);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueCreate);
+
+
+RTDECL(int) RTReqQueueDestroy(RTREQQUEUE hQueue)
+{
+    /*
+     * Check input.
+     */
+    if (hQueue == NIL_RTREQQUEUE)
+        return VINF_SUCCESS;
+    PRTREQQUEUEINT pQueue = hQueue;
+    AssertPtrReturn(pQueue, VERR_INVALID_HANDLE);
+    AssertReturn(ASMAtomicCmpXchgU32(&pQueue->u32Magic, RTREQQUEUE_MAGIC_DEAD, RTREQQUEUE_MAGIC), VERR_INVALID_HANDLE);
+
+    RTSemEventDestroy(pQueue->EventSem);
+    pQueue->EventSem = NIL_RTSEMEVENT;
+
+    for (unsigned i = 0; i < RT_ELEMENTS(pQueue->apReqFree); i++)
+    {
+        PRTREQ pReq = (PRTREQ)ASMAtomicXchgPtr((void **)&pQueue->apReqFree[i], NULL);
+        while (pReq)
+        {
+            PRTREQ pNext = pReq->pNext;
+            rtReqFreeIt(pReq);
+            pReq = pNext;
+        }
+    }
+
+    RTMemFree(pQueue);
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTReqQueueDestroy);
+
+
+RTDECL(int) RTReqQueueProcess(RTREQQUEUE hQueue, RTMSINTERVAL cMillies)
+{
+    LogFlow(("RTReqQueueProcess %x\n", hQueue));
+
+    /*
+     * Check input.
+     */
+    PRTREQQUEUEINT pQueue = hQueue;
+    AssertPtrReturn(pQueue, VERR_INVALID_HANDLE);
+    AssertReturn(pQueue->u32Magic == RTREQQUEUE_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Process loop.  Stop (break) after the first non-VINF_SUCCESS status code.
+     */
+    int rc = VINF_SUCCESS;
+    for (;;)
+    {
+        /*
+         * Get pending requests.
+         */
+        PRTREQ pReqs = ASMAtomicXchgPtrT(&pQueue->pAlreadyPendingReqs, NULL, PRTREQ);
+        if (RT_LIKELY(!pReqs))
+        {
+            pReqs = ASMAtomicXchgPtrT(&pQueue->pReqs, NULL, PRTREQ);
+            if (!pReqs)
+            {
+                /* We do not adjust cMillies (documented behavior). */
+                ASMAtomicWriteBool(&pQueue->fBusy, false); /* this aint 100% perfect, but it's good enough for now... */
+                rc = RTSemEventWait(pQueue->EventSem, cMillies);
+                if (rc != VINF_SUCCESS)
+                    break;
+                continue;
+            }
+
+            ASMAtomicWriteBool(&pQueue->fBusy, true);
+
+            /*
+             * Reverse the list to process it in FIFO order.
+             */
+            PRTREQ pReq = pReqs;
+            if (pReq->pNext)
+                Log2(("RTReqQueueProcess: 2+ requests: %p %p %p\n", pReq, pReq->pNext, pReq->pNext->pNext));
+            pReqs = NULL;
+            while (pReq)
+            {
+                Assert(pReq->enmState == RTREQSTATE_QUEUED);
+                Assert(pReq->uOwner.hQueue == pQueue);
+                PRTREQ pCur = pReq;
+                pReq = pReq->pNext;
+                pCur->pNext = pReqs;
+                pReqs = pCur;
+            }
+
+        }
+        else
+            ASMAtomicWriteBool(&pQueue->fBusy, true);
+
+        /*
+         * Process the requests.
+         */
+        while (pReqs)
+        {
+            /* Unchain the first request and advance the list. */
+            PRTREQ pReq = pReqs;
+            pReqs = pReqs->pNext;
+            pReq->pNext = NULL;
+
+            /* Process the request. */
+            rc = rtReqProcessOne(pReq);
+            if (rc != VINF_SUCCESS)
+            {
+                /* Propagate the return code to caller.  If more requests pending, queue them for later. */
+                if (pReqs)
+                {
+                    pReqs = ASMAtomicXchgPtrT(&pQueue->pAlreadyPendingReqs, pReqs, PRTREQ);
+                    Assert(!pReqs);
+                }
+                break;
+            }
+        }
+        if (rc != VINF_SUCCESS)
+            break;
+    }
+
+    LogFlow(("RTReqQueueProcess: returns %Rrc\n", rc));
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueProcess);
+
+
+RTDECL(int) RTReqQueueCall(RTREQQUEUE hQueue, PRTREQ *ppReq, RTMSINTERVAL cMillies, PFNRT pfnFunction, unsigned cArgs, ...)
+{
+    va_list va;
+    va_start(va, cArgs);
+    int rc = RTReqQueueCallV(hQueue, ppReq, cMillies, RTREQFLAGS_IPRT_STATUS, pfnFunction, cArgs, va);
+    va_end(va);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueCall);
+
+
+RTDECL(int) RTReqQueueCallVoid(RTREQQUEUE hQueue, PRTREQ *ppReq, RTMSINTERVAL cMillies, PFNRT pfnFunction, unsigned cArgs, ...)
+{
+    va_list va;
+    va_start(va, cArgs);
+    int rc = RTReqQueueCallV(hQueue, ppReq, cMillies, RTREQFLAGS_VOID, pfnFunction, cArgs, va);
+    va_end(va);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueCallVoid);
+
+
+RTDECL(int) RTReqQueueCallEx(RTREQQUEUE hQueue, PRTREQ *ppReq, RTMSINTERVAL cMillies, unsigned fFlags, PFNRT pfnFunction, unsigned cArgs, ...)
+{
+    va_list va;
+    va_start(va, cArgs);
+    int rc = RTReqQueueCallV(hQueue, ppReq, cMillies, fFlags, pfnFunction, cArgs, va);
+    va_end(va);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueCallEx);
+
+
+RTDECL(int) RTReqQueueCallV(RTREQQUEUE hQueue, PRTREQ *ppReq, RTMSINTERVAL cMillies, unsigned fFlags, PFNRT pfnFunction, unsigned cArgs, va_list Args)
+{
+    LogFlow(("RTReqQueueCallV: cMillies=%d fFlags=%#x pfnFunction=%p cArgs=%d\n", cMillies, fFlags, pfnFunction, cArgs));
+
+    /*
+     * Check input.
+     */
+    PRTREQQUEUEINT pQueue = hQueue;
+    AssertPtrReturn(pQueue, VERR_INVALID_HANDLE);
+    AssertReturn(pQueue->u32Magic == RTREQQUEUE_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfnFunction, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~(RTREQFLAGS_RETURN_MASK | RTREQFLAGS_NO_WAIT)), VERR_INVALID_PARAMETER);
+
+    if (!(fFlags & RTREQFLAGS_NO_WAIT) || ppReq)
+    {
+        AssertPtrReturn(ppReq, VERR_INVALID_POINTER);
+        *ppReq = NIL_RTREQ;
+    }
+
+    PRTREQ pReq = NULL;
+    AssertMsgReturn(cArgs * sizeof(uintptr_t) <= sizeof(pReq->u.Internal.aArgs), ("cArgs=%u\n", cArgs), VERR_TOO_MUCH_DATA);
+
+    /*
+     * Allocate request
+     */
+    int rc = RTReqQueueAlloc(pQueue, RTREQTYPE_INTERNAL, &pReq);
+    if (rc != VINF_SUCCESS)
+        return rc;
+
+    /*
+     * Initialize the request data.
+     */
+    pReq->fFlags         = fFlags;
+    pReq->u.Internal.pfn = pfnFunction;
+    pReq->u.Internal.cArgs = cArgs;
+    for (unsigned iArg = 0; iArg < cArgs; iArg++)
+        pReq->u.Internal.aArgs[iArg] = va_arg(Args, uintptr_t);
+
+    /*
+     * Queue the request and return.
+     */
+    rc = RTReqSubmit(pReq, cMillies);
+    if (   rc != VINF_SUCCESS
+        && rc != VERR_TIMEOUT)
+    {
+        RTReqRelease(pReq);
+        pReq = NULL;
+    }
+    if (ppReq)
+    {
+        *ppReq = pReq;
+        LogFlow(("RTReqQueueCallV: returns %Rrc *ppReq=%p\n", rc, pReq));
+    }
+    else
+    {
+        RTReqRelease(pReq);
+        LogFlow(("RTReqQueueCallV: returns %Rrc\n", rc));
+    }
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueCallV);
+
+
+RTDECL(bool) RTReqQueueIsBusy(RTREQQUEUE hQueue)
+{
+    PRTREQQUEUEINT pQueue = hQueue;
+    AssertPtrReturn(pQueue, false);
+
+    if (ASMAtomicReadBool(&pQueue->fBusy))
+        return true;
+    if (ASMAtomicReadPtrT(&pQueue->pReqs, PRTREQ) != NULL)
+        return true;
+    if (ASMAtomicReadBool(&pQueue->fBusy))
+        return true;
+    return false;
+}
+RT_EXPORT_SYMBOL(RTReqQueueIsBusy);
+
+
+/**
+ * Joins the list pList with whatever is linked up at *pHead.
+ */
+static void vmr3ReqJoinFreeSub(volatile PRTREQ *ppHead, PRTREQ pList)
+{
+    for (unsigned cIterations = 0;; cIterations++)
+    {
+        PRTREQ pHead = ASMAtomicXchgPtrT(ppHead, pList, PRTREQ);
+        if (!pHead)
+            return;
+        PRTREQ pTail = pHead;
+        while (pTail->pNext)
+            pTail = pTail->pNext;
+        pTail->pNext = pList;
+        if (ASMAtomicCmpXchgPtr(ppHead, pHead, pList))
+            return;
+        pTail->pNext = NULL;
+        if (ASMAtomicCmpXchgPtr(ppHead, pHead, NULL))
+            return;
+        pList = pHead;
+        Assert(cIterations != 32);
+        Assert(cIterations != 64);
+    }
+}
+
+
+/**
+ * Joins the list pList with whatever is linked up at *pHead.
+ */
+static void vmr3ReqJoinFree(PRTREQQUEUEINT pQueue, PRTREQ pList)
+{
+    /*
+     * Split the list if it's too long.
+     */
+    unsigned cReqs = 1;
+    PRTREQ pTail = pList;
+    while (pTail->pNext)
+    {
+        if (cReqs++ > 25)
+        {
+            const uint32_t i = pQueue->iReqFree;
+            vmr3ReqJoinFreeSub(&pQueue->apReqFree[(i + 2) % RT_ELEMENTS(pQueue->apReqFree)], pTail->pNext);
+
+            pTail->pNext = NULL;
+            vmr3ReqJoinFreeSub(&pQueue->apReqFree[(i + 2 + (i == pQueue->iReqFree)) % RT_ELEMENTS(pQueue->apReqFree)], pTail->pNext);
+            return;
+        }
+        pTail = pTail->pNext;
+    }
+    vmr3ReqJoinFreeSub(&pQueue->apReqFree[(pQueue->iReqFree + 2) % RT_ELEMENTS(pQueue->apReqFree)], pList);
+}
+
+
+RTDECL(int) RTReqQueueAlloc(RTREQQUEUE hQueue, RTREQTYPE enmType, PRTREQ *phReq)
+{
+    /*
+     * Validate input.
+     */
+    PRTREQQUEUEINT pQueue = hQueue;
+    AssertPtrReturn(pQueue, VERR_INVALID_HANDLE);
+    AssertReturn(pQueue->u32Magic == RTREQQUEUE_MAGIC, VERR_INVALID_HANDLE);
+    AssertMsgReturn(enmType > RTREQTYPE_INVALID && enmType < RTREQTYPE_MAX, ("%d\n", enmType), VERR_RT_REQUEST_INVALID_TYPE);
+
+    /*
+     * Try get a recycled packet.
+     *
+     * While this could all be solved with a single list with a lock, it's a sport
+     * of mine to avoid locks.
+     */
+    int cTries = RT_ELEMENTS(pQueue->apReqFree) * 2;
+    while (--cTries >= 0)
+    {
+        PRTREQ volatile *ppHead = &pQueue->apReqFree[ASMAtomicIncU32(&pQueue->iReqFree) % RT_ELEMENTS(pQueue->apReqFree)];
+        PRTREQ pReq = ASMAtomicXchgPtrT(ppHead, NULL, PRTREQ);
+        if (pReq)
+        {
+            PRTREQ pNext = pReq->pNext;
+            if (    pNext
+                &&  !ASMAtomicCmpXchgPtr(ppHead, pNext, NULL))
+                vmr3ReqJoinFree(pQueue, pReq->pNext);
+            ASMAtomicDecU32(&pQueue->cReqFree);
+
+            Assert(pReq->uOwner.hQueue == pQueue);
+            Assert(!pReq->fPoolOrQueue);
+
+            int rc = rtReqReInit(pReq, enmType);
+            if (RT_SUCCESS(rc))
+            {
+                *phReq = pReq;
+                LogFlow(("RTReqQueueAlloc: returns VINF_SUCCESS *phReq=%p recycled\n", pReq));
+                return VINF_SUCCESS;
+            }
+        }
+    }
+
+    /*
+     * Ok, allocate a new one.
+     */
+    int rc = rtReqAlloc(enmType, false /*fPoolOrQueue*/, pQueue, phReq);
+    LogFlow(("RTReqQueueAlloc: returns %Rrc *phReq=%p\n", rc, *phReq));
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTReqQueueAlloc);
+
+
+/**
+ * Recycles a requst.
+ *
+ * @returns true if recycled, false if it should be freed.
+ * @param   pQueue              The queue.
+ * @param   pReq                The request.
+ */
+DECLHIDDEN(bool) rtReqQueueRecycle(PRTREQQUEUEINT pQueue, PRTREQINT pReq)
+{
+    if (   !pQueue
+        || pQueue->cReqFree >= 128)
+        return false;
+
+    ASMAtomicIncU32(&pQueue->cReqFree);
+    PRTREQ volatile *ppHead = &pQueue->apReqFree[ASMAtomicIncU32(&pQueue->iReqFree) % RT_ELEMENTS(pQueue->apReqFree)];
+    PRTREQ pNext;
+    do
+    {
+        pNext = *ppHead;
+        ASMAtomicWritePtr(&pReq->pNext, pNext);
+    } while (!ASMAtomicCmpXchgPtr(ppHead, pReq, pNext));
+
+    return true;
+}
+
+
+/**
+ * Submits a request to the queue.
+ *
+ * @param   pQueue              The queue.
+ * @param   pReq                The request.
+ */
+DECLHIDDEN(void) rtReqQueueSubmit(PRTREQQUEUEINT pQueue, PRTREQINT pReq)
+{
+    PRTREQ pNext;
+    do
+    {
+        pNext = pQueue->pReqs;
+        pReq->pNext = pNext;
+        ASMAtomicWriteBool(&pQueue->fBusy, true);
+    } while (!ASMAtomicCmpXchgPtr(&pQueue->pReqs, pReq, pNext));
+
+    /*
+     * Notify queue thread.
+     */
+    RTSemEventSignal(pQueue->EventSem);
+}
+