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-rw-r--r--hw/virtio-blk.c588
1 files changed, 588 insertions, 0 deletions
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
new file mode 100644
index 0000000000..114c63888f
--- /dev/null
+++ b/hw/virtio-blk.c
@@ -0,0 +1,588 @@
+/*
+ * Virtio Block Device
+ *
+ * Copyright IBM, Corp. 2007
+ *
+ * Authors:
+ * Anthony Liguori <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include <qemu-common.h>
+#include "qemu-error.h"
+#include "trace.h"
+#include "blockdev.h"
+#include "virtio-blk.h"
+#ifdef __linux__
+# include <scsi/sg.h>
+#endif
+
+typedef struct VirtIOBlock
+{
+ VirtIODevice vdev;
+ BlockDriverState *bs;
+ VirtQueue *vq;
+ void *rq;
+ QEMUBH *bh;
+ BlockConf *conf;
+ unsigned short sector_mask;
+ char sn[BLOCK_SERIAL_STRLEN];
+ DeviceState *qdev;
+} VirtIOBlock;
+
+static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
+{
+ return (VirtIOBlock *)vdev;
+}
+
+typedef struct VirtIOBlockReq
+{
+ VirtIOBlock *dev;
+ VirtQueueElement elem;
+ struct virtio_blk_inhdr *in;
+ struct virtio_blk_outhdr *out;
+ struct virtio_scsi_inhdr *scsi;
+ QEMUIOVector qiov;
+ struct VirtIOBlockReq *next;
+} VirtIOBlockReq;
+
+static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
+{
+ VirtIOBlock *s = req->dev;
+
+ trace_virtio_blk_req_complete(req, status);
+
+ stb_p(&req->in->status, status);
+ virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
+ virtio_notify(&s->vdev, s->vq);
+
+ qemu_free(req);
+}
+
+static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
+ int is_read)
+{
+ BlockErrorAction action = bdrv_get_on_error(req->dev->bs, is_read);
+ VirtIOBlock *s = req->dev;
+
+ if (action == BLOCK_ERR_IGNORE) {
+ bdrv_mon_event(s->bs, BDRV_ACTION_IGNORE, is_read);
+ return 0;
+ }
+
+ if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
+ || action == BLOCK_ERR_STOP_ANY) {
+ req->next = s->rq;
+ s->rq = req;
+ bdrv_mon_event(s->bs, BDRV_ACTION_STOP, is_read);
+ vm_stop(0);
+ } else {
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
+ bdrv_mon_event(s->bs, BDRV_ACTION_REPORT, is_read);
+ }
+
+ return 1;
+}
+
+static void virtio_blk_rw_complete(void *opaque, int ret)
+{
+ VirtIOBlockReq *req = opaque;
+
+ trace_virtio_blk_rw_complete(req, ret);
+
+ if (ret) {
+ int is_read = !(ldl_p(&req->out->type) & VIRTIO_BLK_T_OUT);
+ if (virtio_blk_handle_rw_error(req, -ret, is_read))
+ return;
+ }
+
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
+}
+
+static void virtio_blk_flush_complete(void *opaque, int ret)
+{
+ VirtIOBlockReq *req = opaque;
+
+ if (ret) {
+ if (virtio_blk_handle_rw_error(req, -ret, 0)) {
+ return;
+ }
+ }
+
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
+}
+
+static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
+{
+ VirtIOBlockReq *req = qemu_malloc(sizeof(*req));
+ req->dev = s;
+ req->qiov.size = 0;
+ req->next = NULL;
+ return req;
+}
+
+static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
+{
+ VirtIOBlockReq *req = virtio_blk_alloc_request(s);
+
+ if (req != NULL) {
+ if (!virtqueue_pop(s->vq, &req->elem)) {
+ qemu_free(req);
+ return NULL;
+ }
+ }
+
+ return req;
+}
+
+#ifdef __linux__
+static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
+{
+ struct sg_io_hdr hdr;
+ int ret;
+ int status;
+ int i;
+
+ /*
+ * We require at least one output segment each for the virtio_blk_outhdr
+ * and the SCSI command block.
+ *
+ * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
+ * and the sense buffer pointer in the input segments.
+ */
+ if (req->elem.out_num < 2 || req->elem.in_num < 3) {
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
+ return;
+ }
+
+ /*
+ * No support for bidirection commands yet.
+ */
+ if (req->elem.out_num > 2 && req->elem.in_num > 3) {
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
+ return;
+ }
+
+ /*
+ * The scsi inhdr is placed in the second-to-last input segment, just
+ * before the regular inhdr.
+ */
+ req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;
+
+ memset(&hdr, 0, sizeof(struct sg_io_hdr));
+ hdr.interface_id = 'S';
+ hdr.cmd_len = req->elem.out_sg[1].iov_len;
+ hdr.cmdp = req->elem.out_sg[1].iov_base;
+ hdr.dxfer_len = 0;
+
+ if (req->elem.out_num > 2) {
+ /*
+ * If there are more than the minimally required 2 output segments
+ * there is write payload starting from the third iovec.
+ */
+ hdr.dxfer_direction = SG_DXFER_TO_DEV;
+ hdr.iovec_count = req->elem.out_num - 2;
+
+ for (i = 0; i < hdr.iovec_count; i++)
+ hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len;
+
+ hdr.dxferp = req->elem.out_sg + 2;
+
+ } else if (req->elem.in_num > 3) {
+ /*
+ * If we have more than 3 input segments the guest wants to actually
+ * read data.
+ */
+ hdr.dxfer_direction = SG_DXFER_FROM_DEV;
+ hdr.iovec_count = req->elem.in_num - 3;
+ for (i = 0; i < hdr.iovec_count; i++)
+ hdr.dxfer_len += req->elem.in_sg[i].iov_len;
+
+ hdr.dxferp = req->elem.in_sg;
+ } else {
+ /*
+ * Some SCSI commands don't actually transfer any data.
+ */
+ hdr.dxfer_direction = SG_DXFER_NONE;
+ }
+
+ hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base;
+ hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len;
+
+ ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr);
+ if (ret) {
+ status = VIRTIO_BLK_S_UNSUPP;
+ hdr.status = ret;
+ hdr.resid = hdr.dxfer_len;
+ } else if (hdr.status) {
+ status = VIRTIO_BLK_S_IOERR;
+ } else {
+ status = VIRTIO_BLK_S_OK;
+ }
+
+ stl_p(&req->scsi->errors, hdr.status);
+ stl_p(&req->scsi->residual, hdr.resid);
+ stl_p(&req->scsi->sense_len, hdr.sb_len_wr);
+ stl_p(&req->scsi->data_len, hdr.dxfer_len);
+
+ virtio_blk_req_complete(req, status);
+}
+#else
+static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
+{
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
+}
+#endif /* __linux__ */
+
+typedef struct MultiReqBuffer {
+ BlockRequest blkreq[32];
+ unsigned int num_writes;
+} MultiReqBuffer;
+
+static void virtio_submit_multiwrite(BlockDriverState *bs, MultiReqBuffer *mrb)
+{
+ int i, ret;
+
+ if (!mrb->num_writes) {
+ return;
+ }
+
+ ret = bdrv_aio_multiwrite(bs, mrb->blkreq, mrb->num_writes);
+ if (ret != 0) {
+ for (i = 0; i < mrb->num_writes; i++) {
+ if (mrb->blkreq[i].error) {
+ virtio_blk_rw_complete(mrb->blkreq[i].opaque, -EIO);
+ }
+ }
+ }
+
+ mrb->num_writes = 0;
+}
+
+static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
+{
+ BlockDriverAIOCB *acb;
+
+ /*
+ * Make sure all outstanding writes are posted to the backing device.
+ */
+ virtio_submit_multiwrite(req->dev->bs, mrb);
+
+ acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req);
+ if (!acb) {
+ virtio_blk_flush_complete(req, -EIO);
+ }
+}
+
+static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
+{
+ BlockRequest *blkreq;
+ uint64_t sector;
+
+ sector = ldq_p(&req->out->sector);
+
+ trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
+
+ if (sector & req->dev->sector_mask) {
+ virtio_blk_rw_complete(req, -EIO);
+ return;
+ }
+ if (req->qiov.size % req->dev->conf->logical_block_size) {
+ virtio_blk_rw_complete(req, -EIO);
+ return;
+ }
+
+ if (mrb->num_writes == 32) {
+ virtio_submit_multiwrite(req->dev->bs, mrb);
+ }
+
+ blkreq = &mrb->blkreq[mrb->num_writes];
+ blkreq->sector = sector;
+ blkreq->nb_sectors = req->qiov.size / BDRV_SECTOR_SIZE;
+ blkreq->qiov = &req->qiov;
+ blkreq->cb = virtio_blk_rw_complete;
+ blkreq->opaque = req;
+ blkreq->error = 0;
+
+ mrb->num_writes++;
+}
+
+static void virtio_blk_handle_read(VirtIOBlockReq *req)
+{
+ BlockDriverAIOCB *acb;
+ uint64_t sector;
+
+ sector = ldq_p(&req->out->sector);
+
+ if (sector & req->dev->sector_mask) {
+ virtio_blk_rw_complete(req, -EIO);
+ return;
+ }
+ if (req->qiov.size % req->dev->conf->logical_block_size) {
+ virtio_blk_rw_complete(req, -EIO);
+ return;
+ }
+
+ acb = bdrv_aio_readv(req->dev->bs, sector, &req->qiov,
+ req->qiov.size / BDRV_SECTOR_SIZE,
+ virtio_blk_rw_complete, req);
+ if (!acb) {
+ virtio_blk_rw_complete(req, -EIO);
+ }
+}
+
+static void virtio_blk_handle_request(VirtIOBlockReq *req,
+ MultiReqBuffer *mrb)
+{
+ uint32_t type;
+
+ if (req->elem.out_num < 1 || req->elem.in_num < 1) {
+ error_report("virtio-blk missing headers");
+ exit(1);
+ }
+
+ if (req->elem.out_sg[0].iov_len < sizeof(*req->out) ||
+ req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) {
+ error_report("virtio-blk header not in correct element");
+ exit(1);
+ }
+
+ req->out = (void *)req->elem.out_sg[0].iov_base;
+ req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base;
+
+ type = ldl_p(&req->out->type);
+
+ if (type & VIRTIO_BLK_T_FLUSH) {
+ virtio_blk_handle_flush(req, mrb);
+ } else if (type & VIRTIO_BLK_T_SCSI_CMD) {
+ virtio_blk_handle_scsi(req);
+ } else if (type & VIRTIO_BLK_T_GET_ID) {
+ VirtIOBlock *s = req->dev;
+
+ memcpy(req->elem.in_sg[0].iov_base, s->sn,
+ MIN(req->elem.in_sg[0].iov_len, sizeof(s->sn)));
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
+ } else if (type & VIRTIO_BLK_T_OUT) {
+ qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
+ req->elem.out_num - 1);
+ virtio_blk_handle_write(req, mrb);
+ } else {
+ qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
+ req->elem.in_num - 1);
+ virtio_blk_handle_read(req);
+ }
+}
+
+static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+ VirtIOBlock *s = to_virtio_blk(vdev);
+ VirtIOBlockReq *req;
+ MultiReqBuffer mrb = {
+ .num_writes = 0,
+ };
+
+ while ((req = virtio_blk_get_request(s))) {
+ virtio_blk_handle_request(req, &mrb);
+ }
+
+ virtio_submit_multiwrite(s->bs, &mrb);
+
+ /*
+ * FIXME: Want to check for completions before returning to guest mode,
+ * so cached reads and writes are reported as quickly as possible. But
+ * that should be done in the generic block layer.
+ */
+}
+
+static void virtio_blk_dma_restart_bh(void *opaque)
+{
+ VirtIOBlock *s = opaque;
+ VirtIOBlockReq *req = s->rq;
+ MultiReqBuffer mrb = {
+ .num_writes = 0,
+ };
+
+ qemu_bh_delete(s->bh);
+ s->bh = NULL;
+
+ s->rq = NULL;
+
+ while (req) {
+ virtio_blk_handle_request(req, &mrb);
+ req = req->next;
+ }
+
+ virtio_submit_multiwrite(s->bs, &mrb);
+}
+
+static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason)
+{
+ VirtIOBlock *s = opaque;
+
+ if (!running)
+ return;
+
+ if (!s->bh) {
+ s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s);
+ qemu_bh_schedule(s->bh);
+ }
+}
+
+static void virtio_blk_reset(VirtIODevice *vdev)
+{
+ /*
+ * This should cancel pending requests, but can't do nicely until there
+ * are per-device request lists.
+ */
+ qemu_aio_flush();
+}
+
+/* coalesce internal state, copy to pci i/o region 0
+ */
+static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
+{
+ VirtIOBlock *s = to_virtio_blk(vdev);
+ struct virtio_blk_config blkcfg;
+ uint64_t capacity;
+ int cylinders, heads, secs;
+
+ bdrv_get_geometry(s->bs, &capacity);
+ bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs);
+ memset(&blkcfg, 0, sizeof(blkcfg));
+ stq_raw(&blkcfg.capacity, capacity);
+ stl_raw(&blkcfg.seg_max, 128 - 2);
+ stw_raw(&blkcfg.cylinders, cylinders);
+ blkcfg.heads = heads;
+ blkcfg.sectors = secs & ~s->sector_mask;
+ blkcfg.blk_size = s->conf->logical_block_size;
+ blkcfg.size_max = 0;
+ blkcfg.physical_block_exp = get_physical_block_exp(s->conf);
+ blkcfg.alignment_offset = 0;
+ blkcfg.min_io_size = s->conf->min_io_size / blkcfg.blk_size;
+ blkcfg.opt_io_size = s->conf->opt_io_size / blkcfg.blk_size;
+ memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
+}
+
+static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
+{
+ VirtIOBlock *s = to_virtio_blk(vdev);
+
+ features |= (1 << VIRTIO_BLK_F_SEG_MAX);
+ features |= (1 << VIRTIO_BLK_F_GEOMETRY);
+ features |= (1 << VIRTIO_BLK_F_TOPOLOGY);
+ features |= (1 << VIRTIO_BLK_F_BLK_SIZE);
+
+ if (bdrv_enable_write_cache(s->bs))
+ features |= (1 << VIRTIO_BLK_F_WCACHE);
+
+ if (bdrv_is_read_only(s->bs))
+ features |= 1 << VIRTIO_BLK_F_RO;
+
+ return features;
+}
+
+static void virtio_blk_save(QEMUFile *f, void *opaque)
+{
+ VirtIOBlock *s = opaque;
+ VirtIOBlockReq *req = s->rq;
+
+ virtio_save(&s->vdev, f);
+
+ while (req) {
+ qemu_put_sbyte(f, 1);
+ qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
+ req = req->next;
+ }
+ qemu_put_sbyte(f, 0);
+}
+
+static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id)
+{
+ VirtIOBlock *s = opaque;
+
+ if (version_id != 2)
+ return -EINVAL;
+
+ virtio_load(&s->vdev, f);
+ while (qemu_get_sbyte(f)) {
+ VirtIOBlockReq *req = virtio_blk_alloc_request(s);
+ qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
+ req->next = s->rq;
+ s->rq = req;
+
+ virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr,
+ req->elem.in_num, 1);
+ virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr,
+ req->elem.out_num, 0);
+ }
+
+ return 0;
+}
+
+static void virtio_blk_change_cb(void *opaque, int reason)
+{
+ VirtIOBlock *s = opaque;
+
+ if (reason & CHANGE_SIZE) {
+ virtio_notify_config(&s->vdev);
+ }
+}
+
+VirtIODevice *virtio_blk_init(DeviceState *dev, BlockConf *conf)
+{
+ VirtIOBlock *s;
+ int cylinders, heads, secs;
+ static int virtio_blk_id;
+ DriveInfo *dinfo;
+
+ if (!conf->bs) {
+ error_report("virtio-blk-pci: drive property not set");
+ return NULL;
+ }
+ if (!bdrv_is_inserted(conf->bs)) {
+ error_report("Device needs media, but drive is empty");
+ return NULL;
+ }
+
+ s = (VirtIOBlock *)virtio_common_init("virtio-blk", VIRTIO_ID_BLOCK,
+ sizeof(struct virtio_blk_config),
+ sizeof(VirtIOBlock));
+
+ s->vdev.get_config = virtio_blk_update_config;
+ s->vdev.get_features = virtio_blk_get_features;
+ s->vdev.reset = virtio_blk_reset;
+ s->bs = conf->bs;
+ s->conf = conf;
+ s->rq = NULL;
+ s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
+ bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
+
+ /* NB: per existing s/n string convention the string is terminated
+ * by '\0' only when less than sizeof (s->sn)
+ */
+ dinfo = drive_get_by_blockdev(s->bs);
+ strncpy(s->sn, dinfo->serial, sizeof (s->sn));
+
+ s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
+
+ qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
+ s->qdev = dev;
+ register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
+ virtio_blk_save, virtio_blk_load, s);
+ bdrv_set_removable(s->bs, 0);
+ bdrv_set_change_cb(s->bs, virtio_blk_change_cb, s);
+ s->bs->buffer_alignment = conf->logical_block_size;
+
+ add_boot_device_path(conf->bootindex, dev, "/disk@0,0");
+
+ return &s->vdev;
+}
+
+void virtio_blk_exit(VirtIODevice *vdev)
+{
+ VirtIOBlock *s = to_virtio_blk(vdev);
+ unregister_savevm(s->qdev, "virtio-blk", s);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-28 12:27:14 +0000