The bdrv_aio_{read,write} routines can return a NULL pointer when the I/O submission fails. Currently we ignore this and will wait forever for an I/O completion and leading to a hang of the guest. I can easily reproduce this using the native Linux AIO patch, but it's also possible using normal pthreads-based AIO. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
459 lines
13 KiB
C
459 lines
13 KiB
C
/*
|
|
* 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 <sysemu.h>
|
|
#include "virtio-blk.h"
|
|
#include "block_int.h"
|
|
#ifdef __linux__
|
|
# include <scsi/sg.h>
|
|
#endif
|
|
|
|
typedef struct VirtIOBlock
|
|
{
|
|
VirtIODevice vdev;
|
|
BlockDriverState *bs;
|
|
VirtQueue *vq;
|
|
void *rq;
|
|
char serial_str[BLOCK_SERIAL_STRLEN + 1];
|
|
QEMUBH *bh;
|
|
} VirtIOBlock;
|
|
|
|
static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
|
|
{
|
|
return (VirtIOBlock *)vdev;
|
|
}
|
|
|
|
/* store identify data in little endian format
|
|
*/
|
|
static inline void put_le16(uint16_t *p, unsigned int v)
|
|
{
|
|
*p = cpu_to_le16(v);
|
|
}
|
|
|
|
/* copy to *dst from *src, nul pad dst tail as needed to len bytes
|
|
*/
|
|
static inline void padstr(char *dst, const char *src, int len)
|
|
{
|
|
while (len--)
|
|
*dst++ = *src ? *src++ : '\0';
|
|
}
|
|
|
|
/* setup simulated identify data as appropriate for virtio block device
|
|
*
|
|
* ref: AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS)
|
|
*/
|
|
static inline void virtio_identify_template(struct virtio_blk_config *bc)
|
|
{
|
|
uint16_t *p = &bc->identify[0];
|
|
uint64_t lba_sectors = bc->capacity;
|
|
|
|
memset(p, 0, sizeof(bc->identify));
|
|
put_le16(p + 0, 0x0); /* ATA device */
|
|
padstr((char *)(p + 23), QEMU_VERSION, 8); /* firmware revision */
|
|
padstr((char *)(p + 27), "QEMU VIRT_BLK", 40); /* model# */
|
|
put_le16(p + 47, 0x80ff); /* max xfer 255 sectors */
|
|
put_le16(p + 49, 0x0b00); /* support IORDY/LBA/DMA */
|
|
put_le16(p + 59, 0x1ff); /* cur xfer 255 sectors */
|
|
put_le16(p + 80, 0x1f0); /* support ATA8/7/6/5/4 */
|
|
put_le16(p + 81, 0x16);
|
|
put_le16(p + 82, 0x400);
|
|
put_le16(p + 83, 0x400);
|
|
put_le16(p + 100, lba_sectors);
|
|
put_le16(p + 101, lba_sectors >> 16);
|
|
put_le16(p + 102, lba_sectors >> 32);
|
|
put_le16(p + 103, lba_sectors >> 48);
|
|
}
|
|
|
|
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;
|
|
|
|
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_write_error(VirtIOBlockReq *req, int error)
|
|
{
|
|
BlockInterfaceErrorAction action = drive_get_onerror(req->dev->bs);
|
|
VirtIOBlock *s = req->dev;
|
|
|
|
if (action == BLOCK_ERR_IGNORE)
|
|
return 0;
|
|
|
|
if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
|
|
|| action == BLOCK_ERR_STOP_ANY) {
|
|
req->next = s->rq;
|
|
s->rq = req;
|
|
vm_stop(0);
|
|
} else {
|
|
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void virtio_blk_rw_complete(void *opaque, int ret)
|
|
{
|
|
VirtIOBlockReq *req = opaque;
|
|
|
|
if (ret && (req->out->type & VIRTIO_BLK_T_OUT)) {
|
|
if (virtio_blk_handle_write_error(req, -ret))
|
|
return;
|
|
}
|
|
|
|
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
|
|
}
|
|
|
|
static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
|
|
{
|
|
VirtIOBlockReq *req = qemu_mallocz(sizeof(*req));
|
|
req->dev = s;
|
|
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, size = 0;
|
|
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;
|
|
size = sizeof(*req->in) + sizeof(*req->scsi);
|
|
|
|
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;
|
|
size += hdr.dxfer_len;
|
|
} 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;
|
|
size += hdr.mx_sb_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;
|
|
}
|
|
|
|
req->scsi->errors = hdr.status;
|
|
req->scsi->residual = hdr.resid;
|
|
req->scsi->sense_len = hdr.sb_len_wr;
|
|
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__ */
|
|
|
|
static void virtio_blk_handle_write(VirtIOBlockReq *req)
|
|
{
|
|
BlockDriverAIOCB *acb;
|
|
|
|
acb = bdrv_aio_writev(req->dev->bs, req->out->sector, &req->qiov,
|
|
req->qiov.size / 512, virtio_blk_rw_complete, req);
|
|
if (!acb) {
|
|
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
|
|
}
|
|
}
|
|
|
|
static void virtio_blk_handle_read(VirtIOBlockReq *req)
|
|
{
|
|
BlockDriverAIOCB *acb;
|
|
|
|
acb = bdrv_aio_readv(req->dev->bs, req->out->sector, &req->qiov,
|
|
req->qiov.size / 512, virtio_blk_rw_complete, req);
|
|
if (!acb) {
|
|
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
|
|
}
|
|
}
|
|
|
|
static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
|
|
{
|
|
VirtIOBlock *s = to_virtio_blk(vdev);
|
|
VirtIOBlockReq *req;
|
|
|
|
while ((req = virtio_blk_get_request(s))) {
|
|
if (req->elem.out_num < 1 || req->elem.in_num < 1) {
|
|
fprintf(stderr, "virtio-blk missing headers\n");
|
|
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)) {
|
|
fprintf(stderr, "virtio-blk header not in correct element\n");
|
|
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;
|
|
|
|
if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) {
|
|
virtio_blk_handle_scsi(req);
|
|
} else if (req->out->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);
|
|
} else {
|
|
qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
|
|
req->elem.in_num - 1);
|
|
virtio_blk_handle_read(req);
|
|
}
|
|
}
|
|
/*
|
|
* 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;
|
|
|
|
qemu_bh_delete(s->bh);
|
|
s->bh = NULL;
|
|
|
|
s->rq = NULL;
|
|
|
|
while (req) {
|
|
virtio_blk_handle_write(req);
|
|
req = req->next;
|
|
}
|
|
}
|
|
|
|
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;
|
|
blkcfg.size_max = 0;
|
|
virtio_identify_template(&blkcfg);
|
|
memcpy(&blkcfg.identify[VIRTIO_BLK_ID_SN], s->serial_str,
|
|
VIRTIO_BLK_ID_SN_BYTES);
|
|
memcpy(config, &blkcfg, sizeof(blkcfg));
|
|
}
|
|
|
|
static uint32_t virtio_blk_get_features(VirtIODevice *vdev)
|
|
{
|
|
VirtIOBlock *s = to_virtio_blk(vdev);
|
|
uint32_t features = 0;
|
|
|
|
features |= (1 << VIRTIO_BLK_F_SEG_MAX);
|
|
features |= (1 << VIRTIO_BLK_F_GEOMETRY);
|
|
#ifdef __linux__
|
|
features |= (1 << VIRTIO_BLK_F_SCSI);
|
|
#endif
|
|
if (strcmp(s->serial_str, "0"))
|
|
features |= 1 << VIRTIO_BLK_F_IDENTIFY;
|
|
|
|
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->next;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
VirtIODevice *virtio_blk_init(DeviceState *dev, DriveInfo *dinfo)
|
|
{
|
|
VirtIOBlock *s;
|
|
int cylinders, heads, secs;
|
|
static int virtio_blk_id;
|
|
char *ps;
|
|
|
|
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 = dinfo->bdrv;
|
|
s->rq = NULL;
|
|
if (strlen(ps = (char *)drive_get_serial(s->bs)))
|
|
strncpy(s->serial_str, ps, sizeof(s->serial_str));
|
|
else
|
|
snprintf(s->serial_str, sizeof(s->serial_str), "0");
|
|
s->bs->private = dev;
|
|
bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
|
|
bdrv_set_geometry_hint(s->bs, cylinders, heads, secs);
|
|
|
|
s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
|
|
|
|
qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
|
|
register_savevm("virtio-blk", virtio_blk_id++, 2,
|
|
virtio_blk_save, virtio_blk_load, s);
|
|
|
|
return &s->vdev;
|
|
}
|