qemu

win32-aio.c
218 строк · 5.9 Кб
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/*
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 * Block driver for RAW files (win32)
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 *
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 * Copyright (c) 2006 Fabrice Bellard
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to deal
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 * in the Software without restriction, including without limitation the rights
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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 * THE SOFTWARE.
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 */
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#include "qemu/osdep.h"
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#include "qemu/timer.h"
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#include "block/block-io.h"
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#include "block/block_int.h"
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#include "block/aio.h"
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#include "block/raw-aio.h"
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#include "qemu/event_notifier.h"
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#include "qemu/iov.h"
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#include "qemu/memalign.h"
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#include <windows.h>
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#include <winioctl.h>
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#define FTYPE_FILE 0
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#define FTYPE_CD     1
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#define FTYPE_HARDDISK 2
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struct QEMUWin32AIOState {
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    HANDLE hIOCP;
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    EventNotifier e;
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    int count;
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    AioContext *aio_ctx;
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};
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typedef struct QEMUWin32AIOCB {
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    BlockAIOCB common;
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    struct QEMUWin32AIOState *ctx;
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    int nbytes;
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    OVERLAPPED ov;
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    QEMUIOVector *qiov;
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    void *buf;
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    bool is_read;
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    bool is_linear;
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} QEMUWin32AIOCB;
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/*
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 * Completes an AIO request (calls the callback and frees the ACB).
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 */
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static void win32_aio_process_completion(QEMUWin32AIOState *s,
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    QEMUWin32AIOCB *waiocb, DWORD count)
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{
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    int ret;
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    s->count--;
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    if (waiocb->ov.Internal != 0) {
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        ret = -EIO;
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    } else {
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        ret = 0;
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        if (count < waiocb->nbytes) {
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            /* Short reads mean EOF, pad with zeros. */
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            if (waiocb->is_read) {
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                qemu_iovec_memset(waiocb->qiov, count, 0,
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                    waiocb->qiov->size - count);
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            } else {
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                ret = -EINVAL;
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            }
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       }
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    }
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    if (!waiocb->is_linear) {
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        if (ret == 0 && waiocb->is_read) {
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            QEMUIOVector *qiov = waiocb->qiov;
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            iov_from_buf(qiov->iov, qiov->niov, 0, waiocb->buf, qiov->size);
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        }
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        qemu_vfree(waiocb->buf);
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    }
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    waiocb->common.cb(waiocb->common.opaque, ret);
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    qemu_aio_unref(waiocb);
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}
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static void win32_aio_completion_cb(EventNotifier *e)
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{
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    QEMUWin32AIOState *s = container_of(e, QEMUWin32AIOState, e);
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    DWORD count;
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    ULONG_PTR key;
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    OVERLAPPED *ov;
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    event_notifier_test_and_clear(&s->e);
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    while (GetQueuedCompletionStatus(s->hIOCP, &count, &key, &ov, 0)) {
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        QEMUWin32AIOCB *waiocb = container_of(ov, QEMUWin32AIOCB, ov);
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        win32_aio_process_completion(s, waiocb, count);
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    }
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}
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static const AIOCBInfo win32_aiocb_info = {
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    .aiocb_size         = sizeof(QEMUWin32AIOCB),
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};
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BlockAIOCB *win32_aio_submit(BlockDriverState *bs,
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        QEMUWin32AIOState *aio, HANDLE hfile,
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        uint64_t offset, uint64_t bytes, QEMUIOVector *qiov,
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        BlockCompletionFunc *cb, void *opaque, int type)
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{
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    struct QEMUWin32AIOCB *waiocb;
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    DWORD rc;
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    waiocb = qemu_aio_get(&win32_aiocb_info, bs, cb, opaque);
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    waiocb->nbytes = bytes;
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    waiocb->qiov = qiov;
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    waiocb->is_read = (type == QEMU_AIO_READ);
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    if (qiov->niov > 1) {
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        waiocb->buf = qemu_try_blockalign(bs, qiov->size);
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        if (waiocb->buf == NULL) {
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            goto out;
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        }
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        if (type & QEMU_AIO_WRITE) {
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            iov_to_buf(qiov->iov, qiov->niov, 0, waiocb->buf, qiov->size);
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        }
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        waiocb->is_linear = false;
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    } else {
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        waiocb->buf = qiov->iov[0].iov_base;
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        waiocb->is_linear = true;
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    }
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    memset(&waiocb->ov, 0, sizeof(waiocb->ov));
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    waiocb->ov.Offset = (DWORD)offset;
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    waiocb->ov.OffsetHigh = (DWORD)(offset >> 32);
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    waiocb->ov.hEvent = event_notifier_get_handle(&aio->e);
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    aio->count++;
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    if (type & QEMU_AIO_READ) {
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        rc = ReadFile(hfile, waiocb->buf, waiocb->nbytes, NULL, &waiocb->ov);
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    } else {
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        rc = WriteFile(hfile, waiocb->buf, waiocb->nbytes, NULL, &waiocb->ov);
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    }
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    if(rc == 0 && GetLastError() != ERROR_IO_PENDING) {
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        goto out_dec_count;
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    }
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    return &waiocb->common;
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out_dec_count:
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    aio->count--;
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out:
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    qemu_aio_unref(waiocb);
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    return NULL;
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}
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int win32_aio_attach(QEMUWin32AIOState *aio, HANDLE hfile)
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{
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    if (CreateIoCompletionPort(hfile, aio->hIOCP, (ULONG_PTR) 0, 0) == NULL) {
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        return -EINVAL;
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    } else {
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        return 0;
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    }
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}
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void win32_aio_detach_aio_context(QEMUWin32AIOState *aio,
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                                  AioContext *old_context)
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{
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    aio_set_event_notifier(old_context, &aio->e, NULL, NULL, NULL);
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    aio->aio_ctx = NULL;
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}
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void win32_aio_attach_aio_context(QEMUWin32AIOState *aio,
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                                  AioContext *new_context)
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{
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    aio->aio_ctx = new_context;
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    aio_set_event_notifier(new_context, &aio->e, win32_aio_completion_cb,
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                           NULL, NULL);
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}
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QEMUWin32AIOState *win32_aio_init(void)
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{
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    QEMUWin32AIOState *s;
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    s = g_malloc0(sizeof(*s));
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    if (event_notifier_init(&s->e, false) < 0) {
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        goto out_free_state;
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    }
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    s->hIOCP = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
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    if (s->hIOCP == NULL) {
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        goto out_close_efd;
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    }
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    return s;
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out_close_efd:
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    event_notifier_cleanup(&s->e);
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out_free_state:
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    g_free(s);
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    return NULL;
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}
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void win32_aio_cleanup(QEMUWin32AIOState *aio)
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{
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    assert(!aio->aio_ctx);
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    CloseHandle(aio->hIOCP);
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    event_notifier_cleanup(&aio->e);
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    g_free(aio);
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}
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