root / hw / virtio-blk.c @ 47f5ba72
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/*
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* Virtio Block Device
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*
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* Copyright IBM, Corp. 2007
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include <qemu-common.h> |
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#include <sysemu.h> |
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#include "virtio-blk.h" |
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#include "block_int.h" |
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#ifdef __linux__
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# include <scsi/sg.h> |
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#endif
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typedef struct VirtIOBlock |
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{ |
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VirtIODevice vdev; |
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BlockDriverState *bs; |
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VirtQueue *vq; |
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void *rq;
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char serial_str[BLOCK_SERIAL_STRLEN + 1]; |
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QEMUBH *bh; |
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size_t config_size; |
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} VirtIOBlock; |
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static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
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{ |
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return (VirtIOBlock *)vdev;
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} |
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/* store identify data in little endian format
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*/
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static inline void put_le16(uint16_t *p, unsigned int v) |
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{ |
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*p = cpu_to_le16(v); |
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} |
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/* copy to *dst from *src, nul pad dst tail as needed to len bytes
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*/
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static inline void padstr(char *dst, const char *src, int len) |
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{ |
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while (len--)
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*dst++ = *src ? *src++ : '\0';
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} |
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/* setup simulated identify data as appropriate for virtio block device
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*
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* ref: AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS)
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*/
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static inline void virtio_identify_template(struct virtio_blk_config *bc) |
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{ |
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uint16_t *p = &bc->identify[0];
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uint64_t lba_sectors = bc->capacity; |
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memset(p, 0, sizeof(bc->identify)); |
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put_le16(p + 0, 0x0); /* ATA device */ |
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padstr((char *)(p + 23), QEMU_VERSION, 8); /* firmware revision */ |
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padstr((char *)(p + 27), "QEMU VIRT_BLK", 40); /* model# */ |
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put_le16(p + 47, 0x80ff); /* max xfer 255 sectors */ |
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put_le16(p + 49, 0x0b00); /* support IORDY/LBA/DMA */ |
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put_le16(p + 59, 0x1ff); /* cur xfer 255 sectors */ |
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put_le16(p + 80, 0x1f0); /* support ATA8/7/6/5/4 */ |
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put_le16(p + 81, 0x16); |
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put_le16(p + 82, 0x400); |
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put_le16(p + 83, 0x400); |
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put_le16(p + 100, lba_sectors);
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put_le16(p + 101, lba_sectors >> 16); |
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put_le16(p + 102, lba_sectors >> 32); |
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put_le16(p + 103, lba_sectors >> 48); |
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} |
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typedef struct VirtIOBlockReq |
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{ |
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VirtIOBlock *dev; |
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VirtQueueElement elem; |
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struct virtio_blk_inhdr *in;
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struct virtio_blk_outhdr *out;
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struct virtio_scsi_inhdr *scsi;
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QEMUIOVector qiov; |
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struct VirtIOBlockReq *next;
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} VirtIOBlockReq; |
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static void virtio_blk_req_complete(VirtIOBlockReq *req, int status) |
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{ |
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VirtIOBlock *s = req->dev; |
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req->in->status = status; |
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virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
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virtio_notify(&s->vdev, s->vq); |
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qemu_free(req); |
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} |
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static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error, |
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int is_read)
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{ |
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BlockInterfaceErrorAction action = |
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drive_get_on_error(req->dev->bs, is_read); |
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VirtIOBlock *s = req->dev; |
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if (action == BLOCK_ERR_IGNORE)
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return 0; |
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if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
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|| action == BLOCK_ERR_STOP_ANY) { |
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req->next = s->rq; |
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s->rq = req; |
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vm_stop(0);
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} else {
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virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
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} |
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return 1; |
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} |
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static void virtio_blk_rw_complete(void *opaque, int ret) |
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{ |
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VirtIOBlockReq *req = opaque; |
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if (ret) {
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int is_read = !(req->out->type & VIRTIO_BLK_T_OUT);
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if (virtio_blk_handle_rw_error(req, -ret, is_read))
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return;
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} |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); |
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} |
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static void virtio_blk_flush_complete(void *opaque, int ret) |
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{ |
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VirtIOBlockReq *req = opaque; |
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virtio_blk_req_complete(req, ret ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK); |
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} |
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static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
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{ |
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VirtIOBlockReq *req = qemu_mallocz(sizeof(*req));
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req->dev = s; |
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return req;
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} |
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static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
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{ |
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VirtIOBlockReq *req = virtio_blk_alloc_request(s); |
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if (req != NULL) { |
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if (!virtqueue_pop(s->vq, &req->elem)) {
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qemu_free(req); |
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return NULL; |
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} |
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} |
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return req;
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} |
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#ifdef __linux__
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static void virtio_blk_handle_scsi(VirtIOBlockReq *req) |
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{ |
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struct sg_io_hdr hdr;
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int ret, size = 0; |
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int status;
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int i;
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/*
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* We require at least one output segment each for the virtio_blk_outhdr
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* and the SCSI command block.
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*
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* We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
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* and the sense buffer pointer in the input segments.
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*/
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if (req->elem.out_num < 2 || req->elem.in_num < 3) { |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
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return;
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} |
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/*
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* No support for bidirection commands yet.
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*/
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if (req->elem.out_num > 2 && req->elem.in_num > 3) { |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
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return;
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} |
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/*
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* The scsi inhdr is placed in the second-to-last input segment, just
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* before the regular inhdr.
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*/
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req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; |
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size = sizeof(*req->in) + sizeof(*req->scsi); |
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memset(&hdr, 0, sizeof(struct sg_io_hdr)); |
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hdr.interface_id = 'S';
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hdr.cmd_len = req->elem.out_sg[1].iov_len;
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hdr.cmdp = req->elem.out_sg[1].iov_base;
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hdr.dxfer_len = 0;
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if (req->elem.out_num > 2) { |
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/*
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* If there are more than the minimally required 2 output segments
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* there is write payload starting from the third iovec.
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*/
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hdr.dxfer_direction = SG_DXFER_TO_DEV; |
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hdr.iovec_count = req->elem.out_num - 2;
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for (i = 0; i < hdr.iovec_count; i++) |
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hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len;
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hdr.dxferp = req->elem.out_sg + 2;
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} else if (req->elem.in_num > 3) { |
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/*
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* If we have more than 3 input segments the guest wants to actually
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* read data.
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*/
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hdr.dxfer_direction = SG_DXFER_FROM_DEV; |
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hdr.iovec_count = req->elem.in_num - 3;
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for (i = 0; i < hdr.iovec_count; i++) |
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hdr.dxfer_len += req->elem.in_sg[i].iov_len; |
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hdr.dxferp = req->elem.in_sg; |
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size += hdr.dxfer_len; |
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} else {
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/*
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* Some SCSI commands don't actually transfer any data.
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*/
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hdr.dxfer_direction = SG_DXFER_NONE; |
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} |
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hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base;
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hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len;
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size += hdr.mx_sb_len; |
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ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr); |
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if (ret) {
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status = VIRTIO_BLK_S_UNSUPP; |
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hdr.status = ret; |
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hdr.resid = hdr.dxfer_len; |
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} else if (hdr.status) { |
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status = VIRTIO_BLK_S_IOERR; |
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} else {
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status = VIRTIO_BLK_S_OK; |
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} |
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req->scsi->errors = hdr.status; |
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req->scsi->residual = hdr.resid; |
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req->scsi->sense_len = hdr.sb_len_wr; |
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req->scsi->data_len = hdr.dxfer_len; |
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virtio_blk_req_complete(req, status); |
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} |
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#else
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static void virtio_blk_handle_scsi(VirtIOBlockReq *req) |
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{ |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
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} |
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#endif /* __linux__ */ |
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static void do_multiwrite(BlockDriverState *bs, BlockRequest *blkreq, |
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int num_writes)
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{ |
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int i, ret;
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ret = bdrv_aio_multiwrite(bs, blkreq, num_writes); |
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if (ret != 0) { |
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for (i = 0; i < num_writes; i++) { |
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if (blkreq[i].error) {
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virtio_blk_req_complete(blkreq[i].opaque, VIRTIO_BLK_S_IOERR); |
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} |
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} |
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} |
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} |
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static void virtio_blk_handle_flush(VirtIOBlockReq *req) |
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{ |
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BlockDriverAIOCB *acb; |
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acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req); |
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if (!acb) {
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virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
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} |
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} |
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static void virtio_blk_handle_write(BlockRequest *blkreq, int *num_writes, |
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VirtIOBlockReq *req, BlockDriverState **old_bs) |
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{ |
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if (req->dev->bs != *old_bs || *num_writes == 32) { |
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if (*old_bs != NULL) { |
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do_multiwrite(*old_bs, blkreq, *num_writes); |
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} |
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*num_writes = 0;
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*old_bs = req->dev->bs; |
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} |
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blkreq[*num_writes].sector = req->out->sector; |
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blkreq[*num_writes].nb_sectors = req->qiov.size / 512;
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blkreq[*num_writes].qiov = &req->qiov; |
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blkreq[*num_writes].cb = virtio_blk_rw_complete; |
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blkreq[*num_writes].opaque = req; |
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blkreq[*num_writes].error = 0;
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(*num_writes)++; |
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} |
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static void virtio_blk_handle_read(VirtIOBlockReq *req) |
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{ |
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BlockDriverAIOCB *acb; |
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acb = bdrv_aio_readv(req->dev->bs, req->out->sector, &req->qiov, |
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req->qiov.size / 512, virtio_blk_rw_complete, req);
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if (!acb) {
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virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
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} |
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} |
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static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) |
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{ |
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VirtIOBlock *s = to_virtio_blk(vdev); |
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VirtIOBlockReq *req; |
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BlockRequest blkreq[32];
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int num_writes = 0; |
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BlockDriverState *old_bs = NULL;
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while ((req = virtio_blk_get_request(s))) {
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if (req->elem.out_num < 1 || req->elem.in_num < 1) { |
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fprintf(stderr, "virtio-blk missing headers\n");
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exit(1);
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} |
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if (req->elem.out_sg[0].iov_len < sizeof(*req->out) || |
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req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) { |
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fprintf(stderr, "virtio-blk header not in correct element\n");
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exit(1);
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} |
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req->out = (void *)req->elem.out_sg[0].iov_base; |
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req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base; |
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if (req->out->type & VIRTIO_BLK_T_FLUSH) {
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virtio_blk_handle_flush(req); |
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} else if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) { |
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virtio_blk_handle_scsi(req); |
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} else if (req->out->type & VIRTIO_BLK_T_OUT) { |
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qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
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req->elem.out_num - 1);
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virtio_blk_handle_write(blkreq, &num_writes, req, &old_bs); |
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} else {
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qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
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req->elem.in_num - 1);
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virtio_blk_handle_read(req); |
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} |
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} |
360 |
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if (num_writes > 0) { |
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do_multiwrite(old_bs, blkreq, num_writes); |
363 |
} |
364 |
|
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/*
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* FIXME: Want to check for completions before returning to guest mode,
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* so cached reads and writes are reported as quickly as possible. But
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* that should be done in the generic block layer.
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*/
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} |
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static void virtio_blk_dma_restart_bh(void *opaque) |
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{ |
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VirtIOBlock *s = opaque; |
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VirtIOBlockReq *req = s->rq; |
376 |
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qemu_bh_delete(s->bh); |
378 |
s->bh = NULL;
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|
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s->rq = NULL;
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while (req) {
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bdrv_aio_writev(req->dev->bs, req->out->sector, &req->qiov, |
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req->qiov.size / 512, virtio_blk_rw_complete, req);
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req = req->next; |
386 |
} |
387 |
} |
388 |
|
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static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason) |
390 |
{ |
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VirtIOBlock *s = opaque; |
392 |
|
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if (!running)
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return;
|
395 |
|
396 |
if (!s->bh) {
|
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s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s); |
398 |
qemu_bh_schedule(s->bh); |
399 |
} |
400 |
} |
401 |
|
402 |
static void virtio_blk_reset(VirtIODevice *vdev) |
403 |
{ |
404 |
/*
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* This should cancel pending requests, but can't do nicely until there
|
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* are per-device request lists.
|
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*/
|
408 |
qemu_aio_flush(); |
409 |
} |
410 |
|
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/* coalesce internal state, copy to pci i/o region 0
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*/
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413 |
static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) |
414 |
{ |
415 |
VirtIOBlock *s = to_virtio_blk(vdev); |
416 |
struct virtio_blk_config blkcfg;
|
417 |
uint64_t capacity; |
418 |
int cylinders, heads, secs;
|
419 |
|
420 |
bdrv_get_geometry(s->bs, &capacity); |
421 |
bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs); |
422 |
memset(&blkcfg, 0, sizeof(blkcfg)); |
423 |
stq_raw(&blkcfg.capacity, capacity); |
424 |
stl_raw(&blkcfg.seg_max, 128 - 2); |
425 |
stw_raw(&blkcfg.cylinders, cylinders); |
426 |
blkcfg.heads = heads; |
427 |
blkcfg.sectors = secs; |
428 |
blkcfg.size_max = 0;
|
429 |
virtio_identify_template(&blkcfg); |
430 |
memcpy(&blkcfg.identify[VIRTIO_BLK_ID_SN], s->serial_str, |
431 |
VIRTIO_BLK_ID_SN_BYTES); |
432 |
memcpy(config, &blkcfg, s->config_size); |
433 |
} |
434 |
|
435 |
static uint32_t virtio_blk_get_features(VirtIODevice *vdev)
|
436 |
{ |
437 |
VirtIOBlock *s = to_virtio_blk(vdev); |
438 |
uint32_t features = 0;
|
439 |
|
440 |
features |= (1 << VIRTIO_BLK_F_SEG_MAX);
|
441 |
features |= (1 << VIRTIO_BLK_F_GEOMETRY);
|
442 |
|
443 |
if (bdrv_enable_write_cache(s->bs))
|
444 |
features |= (1 << VIRTIO_BLK_F_WCACHE);
|
445 |
#ifdef __linux__
|
446 |
features |= (1 << VIRTIO_BLK_F_SCSI);
|
447 |
#endif
|
448 |
if (strcmp(s->serial_str, "0")) |
449 |
features |= 1 << VIRTIO_BLK_F_IDENTIFY;
|
450 |
|
451 |
if (bdrv_is_read_only(s->bs))
|
452 |
features |= 1 << VIRTIO_BLK_F_RO;
|
453 |
|
454 |
return features;
|
455 |
} |
456 |
|
457 |
static void virtio_blk_save(QEMUFile *f, void *opaque) |
458 |
{ |
459 |
VirtIOBlock *s = opaque; |
460 |
VirtIOBlockReq *req = s->rq; |
461 |
|
462 |
virtio_save(&s->vdev, f); |
463 |
|
464 |
while (req) {
|
465 |
qemu_put_sbyte(f, 1);
|
466 |
qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem)); |
467 |
req = req->next; |
468 |
} |
469 |
qemu_put_sbyte(f, 0);
|
470 |
} |
471 |
|
472 |
static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) |
473 |
{ |
474 |
VirtIOBlock *s = opaque; |
475 |
|
476 |
if (version_id != 2) |
477 |
return -EINVAL;
|
478 |
|
479 |
virtio_load(&s->vdev, f); |
480 |
while (qemu_get_sbyte(f)) {
|
481 |
VirtIOBlockReq *req = virtio_blk_alloc_request(s); |
482 |
qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem)); |
483 |
req->next = s->rq; |
484 |
s->rq = req->next; |
485 |
} |
486 |
|
487 |
return 0; |
488 |
} |
489 |
|
490 |
VirtIODevice *virtio_blk_init(DeviceState *dev, DriveInfo *dinfo) |
491 |
{ |
492 |
VirtIOBlock *s; |
493 |
int cylinders, heads, secs;
|
494 |
static int virtio_blk_id; |
495 |
char *ps = (char *)drive_get_serial(dinfo->bdrv); |
496 |
size_t size = strlen(ps) ? sizeof(struct virtio_blk_config) : |
497 |
offsetof(struct virtio_blk_config, _blk_size);
|
498 |
|
499 |
s = (VirtIOBlock *)virtio_common_init("virtio-blk", VIRTIO_ID_BLOCK,
|
500 |
size, |
501 |
sizeof(VirtIOBlock));
|
502 |
|
503 |
s->config_size = size; |
504 |
s->vdev.get_config = virtio_blk_update_config; |
505 |
s->vdev.get_features = virtio_blk_get_features; |
506 |
s->vdev.reset = virtio_blk_reset; |
507 |
s->bs = dinfo->bdrv; |
508 |
s->rq = NULL;
|
509 |
if (strlen(ps))
|
510 |
strncpy(s->serial_str, ps, sizeof(s->serial_str));
|
511 |
else
|
512 |
snprintf(s->serial_str, sizeof(s->serial_str), "0"); |
513 |
bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs); |
514 |
bdrv_set_geometry_hint(s->bs, cylinders, heads, secs); |
515 |
|
516 |
s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
|
517 |
|
518 |
qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); |
519 |
register_savevm("virtio-blk", virtio_blk_id++, 2, |
520 |
virtio_blk_save, virtio_blk_load, s); |
521 |
|
522 |
return &s->vdev;
|
523 |
} |