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qemu/hw/scsi/virtio-scsi.c
Stefan Hajnoczi be2c42b97c virtio-scsi: reset SCSI devices from main loop thread 
When an IOThread is configured, the ctrl virtqueue is processed in the
IOThread. TMFs that reset SCSI devices are currently called directly
from the IOThread and trigger an assertion failure in blk_drain() from
the following call stack:

virtio_scsi_handle_ctrl_req -> virtio_scsi_do_tmf -> device_code_reset
-> scsi_disk_reset -> scsi_device_purge_requests -> blk_drain

  ../block/block-backend.c:1780: void blk_drain(BlockBackend *): Assertion `qemu_in_main_thread()' failed.

The blk_drain() function is not designed to be called from an IOThread
because it needs the Big QEMU Lock (BQL).

This patch defers TMFs that reset SCSI devices to a Bottom Half (BH)
that runs in the main loop thread under the BQL. This way it's safe to
call blk_drain() and the assertion failure is avoided.

Introduce s->tmf_bh_list for tracking TMF requests that have been
deferred to the BH. When the BH runs it will grab the entire list and
process all requests. Care must be taken to clear the list when the
virtio-scsi device is reset or unrealized. Otherwise deferred TMF
requests could execute later and lead to use-after-free or other
undefined behavior.

The s->resetting counter that's used by TMFs that reset SCSI devices is
accessed from multiple threads. This patch makes that explicit by using
atomic accessor functions. With this patch applied the counter is only
modified by the main loop thread under the BQL but can be read by any
thread.

Reported-by: Qing Wang <qinwang@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230221212218.1378734-4-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23 19:49:35 +01:00

1280 lines
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/*
* Virtio SCSI HBA
*
* Copyright IBM, Corp. 2010
* Copyright Red Hat, Inc. 2011
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
* Paolo Bonzini <pbonzini@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "standard-headers/linux/virtio_ids.h"
#include "hw/virtio/virtio-scsi.h"
#include "migration/qemu-file-types.h"
#include "qemu/error-report.h"
#include "qemu/iov.h"
#include "qemu/module.h"
#include "sysemu/block-backend.h"
#include "sysemu/dma.h"
#include "hw/qdev-properties.h"
#include "hw/scsi/scsi.h"
#include "scsi/constants.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/virtio-access.h"
#include "trace.h"
typedef struct VirtIOSCSIReq {
/*
* Note:
* - fields up to resp_iov are initialized by virtio_scsi_init_req;
* - fields starting at vring are zeroed by virtio_scsi_init_req.
*/
VirtQueueElement elem;
VirtIOSCSI *dev;
VirtQueue *vq;
QEMUSGList qsgl;
QEMUIOVector resp_iov;
/* Used for two-stage request submission and TMFs deferred to BH */
QTAILQ_ENTRY(VirtIOSCSIReq) next;
/* Used for cancellation of request during TMFs */
int remaining;
SCSIRequest *sreq;
size_t resp_size;
enum SCSIXferMode mode;
union {
VirtIOSCSICmdResp cmd;
VirtIOSCSICtrlTMFResp tmf;
VirtIOSCSICtrlANResp an;
VirtIOSCSIEvent event;
} resp;
union {
VirtIOSCSICmdReq cmd;
VirtIOSCSICtrlTMFReq tmf;
VirtIOSCSICtrlANReq an;
} req;
} VirtIOSCSIReq;
static inline int virtio_scsi_get_lun(uint8_t *lun)
{
return ((lun[2] << 8) | lun[3]) & 0x3FFF;
}
static inline SCSIDevice *virtio_scsi_device_get(VirtIOSCSI *s, uint8_t *lun)
{
if (lun[0] != 1) {
return NULL;
}
if (lun[2] != 0 && !(lun[2] >= 0x40 && lun[2] < 0x80)) {
return NULL;
}
return scsi_device_get(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));
}
static void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
{
VirtIODevice *vdev = VIRTIO_DEVICE(s);
const size_t zero_skip =
offsetof(VirtIOSCSIReq, resp_iov) + sizeof(req->resp_iov);
req->vq = vq;
req->dev = s;
qemu_sglist_init(&req->qsgl, DEVICE(s), 8, vdev->dma_as);
qemu_iovec_init(&req->resp_iov, 1);
memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip);
}
static void virtio_scsi_free_req(VirtIOSCSIReq *req)
{
qemu_iovec_destroy(&req->resp_iov);
qemu_sglist_destroy(&req->qsgl);
g_free(req);
}
static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
{
VirtIOSCSI *s = req->dev;
VirtQueue *vq = req->vq;
VirtIODevice *vdev = VIRTIO_DEVICE(s);
qemu_iovec_from_buf(&req->resp_iov, 0, &req->resp, req->resp_size);
virtqueue_push(vq, &req->elem, req->qsgl.size + req->resp_iov.size);
if (s->dataplane_started && !s->dataplane_fenced) {
virtio_notify_irqfd(vdev, vq);
} else {
virtio_notify(vdev, vq);
}
if (req->sreq) {
req->sreq->hba_private = NULL;
scsi_req_unref(req->sreq);
}
virtio_scsi_free_req(req);
}
static void virtio_scsi_bad_req(VirtIOSCSIReq *req)
{
virtio_error(VIRTIO_DEVICE(req->dev), "wrong size for virtio-scsi headers");
virtqueue_detach_element(req->vq, &req->elem, 0);
virtio_scsi_free_req(req);
}
static size_t qemu_sgl_concat(VirtIOSCSIReq *req, struct iovec *iov,
hwaddr *addr, int num, size_t skip)
{
QEMUSGList *qsgl = &req->qsgl;
size_t copied = 0;
while (num) {
if (skip >= iov->iov_len) {
skip -= iov->iov_len;
} else {
qemu_sglist_add(qsgl, *addr + skip, iov->iov_len - skip);
copied += iov->iov_len - skip;
skip = 0;
}
iov++;
addr++;
num--;
}
assert(skip == 0);
return copied;
}
static int virtio_scsi_parse_req(VirtIOSCSIReq *req,
unsigned req_size, unsigned resp_size)
{
VirtIODevice *vdev = (VirtIODevice *) req->dev;
size_t in_size, out_size;
if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
&req->req, req_size) < req_size) {
return -EINVAL;
}
if (qemu_iovec_concat_iov(&req->resp_iov,
req->elem.in_sg, req->elem.in_num, 0,
resp_size) < resp_size) {
return -EINVAL;
}
req->resp_size = resp_size;
/* Old BIOSes left some padding by mistake after the req_size/resp_size.
* As a workaround, always consider the first buffer as the virtio-scsi
* request/response, making the payload start at the second element
* of the iovec.
*
* The actual length of the response header, stored in req->resp_size,
* does not change.
*
* TODO: always disable this workaround for virtio 1.0 devices.
*/
if (!virtio_vdev_has_feature(vdev, VIRTIO_F_ANY_LAYOUT)) {
if (req->elem.out_num) {
req_size = req->elem.out_sg[0].iov_len;
}
if (req->elem.in_num) {
resp_size = req->elem.in_sg[0].iov_len;
}
}
out_size = qemu_sgl_concat(req, req->elem.out_sg,
&req->elem.out_addr[0], req->elem.out_num,
req_size);
in_size = qemu_sgl_concat(req, req->elem.in_sg,
&req->elem.in_addr[0], req->elem.in_num,
resp_size);
if (out_size && in_size) {
return -ENOTSUP;
}
if (out_size) {
req->mode = SCSI_XFER_TO_DEV;
} else if (in_size) {
req->mode = SCSI_XFER_FROM_DEV;
}
return 0;
}
static VirtIOSCSIReq *virtio_scsi_pop_req(VirtIOSCSI *s, VirtQueue *vq)
{
VirtIOSCSICommon *vs = (VirtIOSCSICommon *)s;
VirtIOSCSIReq *req;
req = virtqueue_pop(vq, sizeof(VirtIOSCSIReq) + vs->cdb_size);
if (!req) {
return NULL;
}
virtio_scsi_init_req(s, vq, req);
return req;
}
static void virtio_scsi_save_request(QEMUFile *f, SCSIRequest *sreq)
{
VirtIOSCSIReq *req = sreq->hba_private;
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(req->dev);
VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
uint32_t n = virtio_get_queue_index(req->vq) - VIRTIO_SCSI_VQ_NUM_FIXED;
assert(n < vs->conf.num_queues);
qemu_put_be32s(f, &n);
qemu_put_virtqueue_element(vdev, f, &req->elem);
}
static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq)
{
SCSIBus *bus = sreq->bus;
VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
VirtIODevice *vdev = VIRTIO_DEVICE(s);
VirtIOSCSIReq *req;
uint32_t n;
qemu_get_be32s(f, &n);
assert(n < vs->conf.num_queues);
req = qemu_get_virtqueue_element(vdev, f,
sizeof(VirtIOSCSIReq) + vs->cdb_size);
virtio_scsi_init_req(s, vs->cmd_vqs[n], req);
if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
sizeof(VirtIOSCSICmdResp) + vs->sense_size) < 0) {
error_report("invalid SCSI request migration data");
exit(1);
}
scsi_req_ref(sreq);
req->sreq = sreq;
if (req->sreq->cmd.mode != SCSI_XFER_NONE) {
assert(req->sreq->cmd.mode == req->mode);
}
return req;
}
typedef struct {
Notifier notifier;
VirtIOSCSIReq *tmf_req;
} VirtIOSCSICancelNotifier;
static void virtio_scsi_cancel_notify(Notifier *notifier, void *data)
{
VirtIOSCSICancelNotifier *n = container_of(notifier,
VirtIOSCSICancelNotifier,
notifier);
if (--n->tmf_req->remaining == 0) {
VirtIOSCSIReq *req = n->tmf_req;
trace_virtio_scsi_tmf_resp(virtio_scsi_get_lun(req->req.tmf.lun),
req->req.tmf.tag, req->resp.tmf.response);
virtio_scsi_complete_req(req);
}
g_free(n);
}
static inline void virtio_scsi_ctx_check(VirtIOSCSI *s, SCSIDevice *d)
{
if (s->dataplane_started && d && blk_is_available(d->conf.blk)) {
assert(blk_get_aio_context(d->conf.blk) == s->ctx);
}
}
static void virtio_scsi_do_one_tmf_bh(VirtIOSCSIReq *req)
{
VirtIOSCSI *s = req->dev;
SCSIDevice *d = virtio_scsi_device_get(s, req->req.tmf.lun);
BusChild *kid;
int target;
switch (req->req.tmf.subtype) {
case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
if (!d) {
req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
goto out;
}
if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
goto out;
}
qatomic_inc(&s->resetting);
device_cold_reset(&d->qdev);
qatomic_dec(&s->resetting);
break;
case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
target = req->req.tmf.lun[1];
qatomic_inc(&s->resetting);
rcu_read_lock();
QTAILQ_FOREACH_RCU(kid, &s->bus.qbus.children, sibling) {
SCSIDevice *d1 = SCSI_DEVICE(kid->child);
if (d1->channel == 0 && d1->id == target) {
device_cold_reset(&d1->qdev);
}
}
rcu_read_unlock();
qatomic_dec(&s->resetting);
break;
default:
g_assert_not_reached();
break;
}
out:
object_unref(OBJECT(d));
virtio_scsi_acquire(s);
virtio_scsi_complete_req(req);
virtio_scsi_release(s);
}
/* Some TMFs must be processed from the main loop thread */
static void virtio_scsi_do_tmf_bh(void *opaque)
{
VirtIOSCSI *s = opaque;
QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
VirtIOSCSIReq *req;
VirtIOSCSIReq *tmp;
GLOBAL_STATE_CODE();
virtio_scsi_acquire(s);
QTAILQ_FOREACH_SAFE(req, &s->tmf_bh_list, next, tmp) {
QTAILQ_REMOVE(&s->tmf_bh_list, req, next);
QTAILQ_INSERT_TAIL(&reqs, req, next);
}
qemu_bh_delete(s->tmf_bh);
s->tmf_bh = NULL;
virtio_scsi_release(s);
QTAILQ_FOREACH_SAFE(req, &reqs, next, tmp) {
QTAILQ_REMOVE(&reqs, req, next);
virtio_scsi_do_one_tmf_bh(req);
}
}
static void virtio_scsi_reset_tmf_bh(VirtIOSCSI *s)
{
VirtIOSCSIReq *req;
VirtIOSCSIReq *tmp;
GLOBAL_STATE_CODE();
virtio_scsi_acquire(s);
if (s->tmf_bh) {
qemu_bh_delete(s->tmf_bh);
s->tmf_bh = NULL;
}
QTAILQ_FOREACH_SAFE(req, &s->tmf_bh_list, next, tmp) {
QTAILQ_REMOVE(&s->tmf_bh_list, req, next);
/* SAM-6 6.3.2 Hard reset */
req->resp.tmf.response = VIRTIO_SCSI_S_TARGET_FAILURE;
virtio_scsi_complete_req(req);
}
virtio_scsi_release(s);
}
static void virtio_scsi_defer_tmf_to_bh(VirtIOSCSIReq *req)
{
VirtIOSCSI *s = req->dev;
QTAILQ_INSERT_TAIL(&s->tmf_bh_list, req, next);
if (!s->tmf_bh) {
s->tmf_bh = qemu_bh_new(virtio_scsi_do_tmf_bh, s);
qemu_bh_schedule(s->tmf_bh);
}
}
/* Return 0 if the request is ready to be completed and return to guest;
* -EINPROGRESS if the request is submitted and will be completed later, in the
* case of async cancellation. */
static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
{
SCSIDevice *d = virtio_scsi_device_get(s, req->req.tmf.lun);
SCSIRequest *r, *next;
int ret = 0;
virtio_scsi_ctx_check(s, d);
/* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE". */
req->resp.tmf.response = VIRTIO_SCSI_S_OK;
/*
* req->req.tmf has the QEMU_PACKED attribute. Don't use virtio_tswap32s()
* to avoid compiler errors.
*/
req->req.tmf.subtype =
virtio_tswap32(VIRTIO_DEVICE(s), req->req.tmf.subtype);
trace_virtio_scsi_tmf_req(virtio_scsi_get_lun(req->req.tmf.lun),
req->req.tmf.tag, req->req.tmf.subtype);
switch (req->req.tmf.subtype) {
case VIRTIO_SCSI_T_TMF_ABORT_TASK:
case VIRTIO_SCSI_T_TMF_QUERY_TASK:
if (!d) {
goto fail;
}
if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
goto incorrect_lun;
}
QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
VirtIOSCSIReq *cmd_req = r->hba_private;
if (cmd_req && cmd_req->req.cmd.tag == req->req.tmf.tag) {
break;
}
}
if (r) {
/*
* Assert that the request has not been completed yet, we
* check for it in the loop above.
*/
assert(r->hba_private);
if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK) {
/* "If the specified command is present in the task set, then
* return a service response set to FUNCTION SUCCEEDED".
*/
req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
} else {
VirtIOSCSICancelNotifier *notifier;
req->remaining = 1;
notifier = g_new(VirtIOSCSICancelNotifier, 1);
notifier->tmf_req = req;
notifier->notifier.notify = virtio_scsi_cancel_notify;
scsi_req_cancel_async(r, &notifier->notifier);
ret = -EINPROGRESS;
}
}
break;
case VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET:
case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
virtio_scsi_defer_tmf_to_bh(req);
ret = -EINPROGRESS;
break;
case VIRTIO_SCSI_T_TMF_ABORT_TASK_SET:
case VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET:
case VIRTIO_SCSI_T_TMF_QUERY_TASK_SET:
if (!d) {
goto fail;
}
if (d->lun != virtio_scsi_get_lun(req->req.tmf.lun)) {
goto incorrect_lun;
}
/* Add 1 to "remaining" until virtio_scsi_do_tmf returns.
* This way, if the bus starts calling back to the notifiers
* even before we finish the loop, virtio_scsi_cancel_notify
* will not complete the TMF too early.
*/
req->remaining = 1;
QTAILQ_FOREACH_SAFE(r, &d->requests, next, next) {
if (r->hba_private) {
if (req->req.tmf.subtype == VIRTIO_SCSI_T_TMF_QUERY_TASK_SET) {
/* "If there is any command present in the task set, then
* return a service response set to FUNCTION SUCCEEDED".
*/
req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_SUCCEEDED;
break;
} else {
VirtIOSCSICancelNotifier *notifier;
req->remaining++;
notifier = g_new(VirtIOSCSICancelNotifier, 1);
notifier->notifier.notify = virtio_scsi_cancel_notify;
notifier->tmf_req = req;
scsi_req_cancel_async(r, &notifier->notifier);
}
}
}
if (--req->remaining > 0) {
ret = -EINPROGRESS;
}
break;
case VIRTIO_SCSI_T_TMF_CLEAR_ACA:
default:
req->resp.tmf.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
break;
}
object_unref(OBJECT(d));
return ret;
incorrect_lun:
req->resp.tmf.response = VIRTIO_SCSI_S_INCORRECT_LUN;
object_unref(OBJECT(d));
return ret;
fail:
req->resp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
object_unref(OBJECT(d));
return ret;
}
static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
{
VirtIODevice *vdev = (VirtIODevice *)s;
uint32_t type;
int r = 0;
if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
&type, sizeof(type)) < sizeof(type)) {
virtio_scsi_bad_req(req);
return;
}
virtio_tswap32s(vdev, &type);
if (type == VIRTIO_SCSI_T_TMF) {
if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlTMFReq),
sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
virtio_scsi_bad_req(req);
return;
} else {
r = virtio_scsi_do_tmf(s, req);
}
} else if (type == VIRTIO_SCSI_T_AN_QUERY ||
type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlANReq),
sizeof(VirtIOSCSICtrlANResp)) < 0) {
virtio_scsi_bad_req(req);
return;
} else {
req->req.an.event_requested =
virtio_tswap32(VIRTIO_DEVICE(s), req->req.an.event_requested);
trace_virtio_scsi_an_req(virtio_scsi_get_lun(req->req.an.lun),
req->req.an.event_requested);
req->resp.an.event_actual = 0;
req->resp.an.response = VIRTIO_SCSI_S_OK;
}
}
if (r == 0) {
if (type == VIRTIO_SCSI_T_TMF)
trace_virtio_scsi_tmf_resp(virtio_scsi_get_lun(req->req.tmf.lun),
req->req.tmf.tag,
req->resp.tmf.response);
else if (type == VIRTIO_SCSI_T_AN_QUERY ||
type == VIRTIO_SCSI_T_AN_SUBSCRIBE)
trace_virtio_scsi_an_resp(virtio_scsi_get_lun(req->req.an.lun),
req->resp.an.response);
virtio_scsi_complete_req(req);
} else {
assert(r == -EINPROGRESS);
}
}
static void virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
{
VirtIOSCSIReq *req;
while ((req = virtio_scsi_pop_req(s, vq))) {
virtio_scsi_handle_ctrl_req(s, req);
}
}
/*
* If dataplane is configured but not yet started, do so now and return true on
* success.
*
* Dataplane is started by the core virtio code but virtqueue handler functions
* can also be invoked when a guest kicks before DRIVER_OK, so this helper
* function helps us deal with manually starting ioeventfd in that case.
*/
static bool virtio_scsi_defer_to_dataplane(VirtIOSCSI *s)
{
if (!s->ctx || s->dataplane_started) {
return false;
}
virtio_device_start_ioeventfd(&s->parent_obj.parent_obj);
return !s->dataplane_fenced;
}
static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
if (virtio_scsi_defer_to_dataplane(s)) {
return;
}
virtio_scsi_acquire(s);
virtio_scsi_handle_ctrl_vq(s, vq);
virtio_scsi_release(s);
}
static void virtio_scsi_complete_cmd_req(VirtIOSCSIReq *req)
{
trace_virtio_scsi_cmd_resp(virtio_scsi_get_lun(req->req.cmd.lun),
req->req.cmd.tag,
req->resp.cmd.response,
req->resp.cmd.status);
/* Sense data is not in req->resp and is copied separately
* in virtio_scsi_command_complete.
*/
req->resp_size = sizeof(VirtIOSCSICmdResp);
virtio_scsi_complete_req(req);
}
static void virtio_scsi_command_failed(SCSIRequest *r)
{
VirtIOSCSIReq *req = r->hba_private;
if (r->io_canceled) {
return;
}
req->resp.cmd.status = GOOD;
switch (r->host_status) {
case SCSI_HOST_NO_LUN:
req->resp.cmd.response = VIRTIO_SCSI_S_INCORRECT_LUN;
break;
case SCSI_HOST_BUSY:
req->resp.cmd.response = VIRTIO_SCSI_S_BUSY;
break;
case SCSI_HOST_TIME_OUT:
case SCSI_HOST_ABORTED:
req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
break;
case SCSI_HOST_BAD_RESPONSE:
req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
break;
case SCSI_HOST_RESET:
req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
break;
case SCSI_HOST_TRANSPORT_DISRUPTED:
req->resp.cmd.response = VIRTIO_SCSI_S_TRANSPORT_FAILURE;
break;
case SCSI_HOST_TARGET_FAILURE:
req->resp.cmd.response = VIRTIO_SCSI_S_TARGET_FAILURE;
break;
case SCSI_HOST_RESERVATION_ERROR:
req->resp.cmd.response = VIRTIO_SCSI_S_NEXUS_FAILURE;
break;
case SCSI_HOST_ALLOCATION_FAILURE:
case SCSI_HOST_MEDIUM_ERROR:
case SCSI_HOST_ERROR:
default:
req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
break;
}
virtio_scsi_complete_cmd_req(req);
}
static void virtio_scsi_command_complete(SCSIRequest *r, size_t resid)
{
VirtIOSCSIReq *req = r->hba_private;
uint8_t sense[SCSI_SENSE_BUF_SIZE];
uint32_t sense_len;
VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
if (r->io_canceled) {
return;
}
req->resp.cmd.response = VIRTIO_SCSI_S_OK;
req->resp.cmd.status = r->status;
if (req->resp.cmd.status == GOOD) {
req->resp.cmd.resid = virtio_tswap32(vdev, resid);
} else {
req->resp.cmd.resid = 0;
sense_len = scsi_req_get_sense(r, sense, sizeof(sense));
sense_len = MIN(sense_len, req->resp_iov.size - sizeof(req->resp.cmd));
qemu_iovec_from_buf(&req->resp_iov, sizeof(req->resp.cmd),
sense, sense_len);
req->resp.cmd.sense_len = virtio_tswap32(vdev, sense_len);
}
virtio_scsi_complete_cmd_req(req);
}
static int virtio_scsi_parse_cdb(SCSIDevice *dev, SCSICommand *cmd,
uint8_t *buf, size_t buf_len,
void *hba_private)
{
VirtIOSCSIReq *req = hba_private;
if (cmd->len == 0) {
cmd->len = MIN(VIRTIO_SCSI_CDB_DEFAULT_SIZE, SCSI_CMD_BUF_SIZE);
memcpy(cmd->buf, buf, cmd->len);
}
/* Extract the direction and mode directly from the request, for
* host device passthrough.
*/
cmd->xfer = req->qsgl.size;
cmd->mode = req->mode;
return 0;
}
static QEMUSGList *virtio_scsi_get_sg_list(SCSIRequest *r)
{
VirtIOSCSIReq *req = r->hba_private;
return &req->qsgl;
}
static void virtio_scsi_request_cancelled(SCSIRequest *r)
{
VirtIOSCSIReq *req = r->hba_private;
if (!req) {
return;
}
if (qatomic_read(&req->dev->resetting)) {
req->resp.cmd.response = VIRTIO_SCSI_S_RESET;
} else {
req->resp.cmd.response = VIRTIO_SCSI_S_ABORTED;
}
virtio_scsi_complete_cmd_req(req);
}
static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
{
req->resp.cmd.response = VIRTIO_SCSI_S_FAILURE;
virtio_scsi_complete_cmd_req(req);
}
static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
{
VirtIOSCSICommon *vs = &s->parent_obj;
SCSIDevice *d;
int rc;
rc = virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
sizeof(VirtIOSCSICmdResp) + vs->sense_size);
if (rc < 0) {
if (rc == -ENOTSUP) {
virtio_scsi_fail_cmd_req(req);
return -ENOTSUP;
} else {
virtio_scsi_bad_req(req);
return -EINVAL;
}
}
trace_virtio_scsi_cmd_req(virtio_scsi_get_lun(req->req.cmd.lun),
req->req.cmd.tag, req->req.cmd.cdb[0]);
d = virtio_scsi_device_get(s, req->req.cmd.lun);
if (!d) {
req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
virtio_scsi_complete_cmd_req(req);
return -ENOENT;
}
virtio_scsi_ctx_check(s, d);
req->sreq = scsi_req_new(d, req->req.cmd.tag,
virtio_scsi_get_lun(req->req.cmd.lun),
req->req.cmd.cdb, vs->cdb_size, req);
if (req->sreq->cmd.mode != SCSI_XFER_NONE
&& (req->sreq->cmd.mode != req->mode ||
req->sreq->cmd.xfer > req->qsgl.size)) {
req->resp.cmd.response = VIRTIO_SCSI_S_OVERRUN;
virtio_scsi_complete_cmd_req(req);
object_unref(OBJECT(d));
return -ENOBUFS;
}
scsi_req_ref(req->sreq);
blk_io_plug(d->conf.blk);
object_unref(OBJECT(d));
return 0;
}
static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
{
SCSIRequest *sreq = req->sreq;
if (scsi_req_enqueue(sreq)) {
scsi_req_continue(sreq);
}
blk_io_unplug(sreq->dev->conf.blk);
scsi_req_unref(sreq);
}
static void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
{
VirtIOSCSIReq *req, *next;
int ret = 0;
bool suppress_notifications = virtio_queue_get_notification(vq);
QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
do {
if (suppress_notifications) {
virtio_queue_set_notification(vq, 0);
}
while ((req = virtio_scsi_pop_req(s, vq))) {
ret = virtio_scsi_handle_cmd_req_prepare(s, req);
if (!ret) {
QTAILQ_INSERT_TAIL(&reqs, req, next);
} else if (ret == -EINVAL) {
/* The device is broken and shouldn't process any request */
while (!QTAILQ_EMPTY(&reqs)) {
req = QTAILQ_FIRST(&reqs);
QTAILQ_REMOVE(&reqs, req, next);
blk_io_unplug(req->sreq->dev->conf.blk);
scsi_req_unref(req->sreq);
virtqueue_detach_element(req->vq, &req->elem, 0);
virtio_scsi_free_req(req);
}
}
}
if (suppress_notifications) {
virtio_queue_set_notification(vq, 1);
}
} while (ret != -EINVAL && !virtio_queue_empty(vq));
QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
virtio_scsi_handle_cmd_req_submit(s, req);
}
}
static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
{
/* use non-QOM casts in the data path */
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
if (virtio_scsi_defer_to_dataplane(s)) {
return;
}
virtio_scsi_acquire(s);
virtio_scsi_handle_cmd_vq(s, vq);
virtio_scsi_release(s);
}
static void virtio_scsi_get_config(VirtIODevice *vdev,
uint8_t *config)
{
VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(vdev);
virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues);
virtio_stl_p(vdev, &scsiconf->seg_max,
s->conf.seg_max_adjust ? s->conf.virtqueue_size - 2 : 128 - 2);
virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors);
virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun);
virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
virtio_stl_p(vdev, &scsiconf->sense_size, s->sense_size);
virtio_stl_p(vdev, &scsiconf->cdb_size, s->cdb_size);
virtio_stw_p(vdev, &scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
virtio_stw_p(vdev, &scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
virtio_stl_p(vdev, &scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
}
static void virtio_scsi_set_config(VirtIODevice *vdev,
const uint8_t *config)
{
VirtIOSCSIConfig *scsiconf = (VirtIOSCSIConfig *)config;
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
if ((uint32_t) virtio_ldl_p(vdev, &scsiconf->sense_size) >= 65536 ||
(uint32_t) virtio_ldl_p(vdev, &scsiconf->cdb_size) >= 256) {
virtio_error(vdev,
"bad data written to virtio-scsi configuration space");
return;
}
vs->sense_size = virtio_ldl_p(vdev, &scsiconf->sense_size);
vs->cdb_size = virtio_ldl_p(vdev, &scsiconf->cdb_size);
}
static uint64_t virtio_scsi_get_features(VirtIODevice *vdev,
uint64_t requested_features,
Error **errp)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
/* Firstly sync all virtio-scsi possible supported features */
requested_features |= s->host_features;
return requested_features;
}
static void virtio_scsi_reset(VirtIODevice *vdev)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
assert(!s->dataplane_started);
virtio_scsi_reset_tmf_bh(s);
qatomic_inc(&s->resetting);
bus_cold_reset(BUS(&s->bus));
qatomic_dec(&s->resetting);
vs->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
vs->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
s->events_dropped = false;
}
static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
uint32_t event, uint32_t reason)
{
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
VirtIOSCSIReq *req;
VirtIOSCSIEvent *evt;
VirtIODevice *vdev = VIRTIO_DEVICE(s);
if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
return;
}
req = virtio_scsi_pop_req(s, vs->event_vq);
if (!req) {
s->events_dropped = true;
return;
}
if (s->events_dropped) {
event |= VIRTIO_SCSI_T_EVENTS_MISSED;
s->events_dropped = false;
}
if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) {
virtio_scsi_bad_req(req);
return;
}
evt = &req->resp.event;
memset(evt, 0, sizeof(VirtIOSCSIEvent));
evt->event = virtio_tswap32(vdev, event);
evt->reason = virtio_tswap32(vdev, reason);
if (!dev) {
assert(event == VIRTIO_SCSI_T_EVENTS_MISSED);
} else {
evt->lun[0] = 1;
evt->lun[1] = dev->id;
/* Linux wants us to keep the same encoding we use for REPORT LUNS. */
if (dev->lun >= 256) {
evt->lun[2] = (dev->lun >> 8) | 0x40;
}
evt->lun[3] = dev->lun & 0xFF;
}
trace_virtio_scsi_event(virtio_scsi_get_lun(evt->lun), event, reason);
virtio_scsi_complete_req(req);
}
static void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
{
if (s->events_dropped) {
virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
}
}
static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
if (virtio_scsi_defer_to_dataplane(s)) {
return;
}
virtio_scsi_acquire(s);
virtio_scsi_handle_event_vq(s, vq);
virtio_scsi_release(s);
}
static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense)
{
VirtIOSCSI *s = container_of(bus, VirtIOSCSI, bus);
VirtIODevice *vdev = VIRTIO_DEVICE(s);
if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_CHANGE) &&
dev->type != TYPE_ROM) {
virtio_scsi_acquire(s);
virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE,
sense.asc | (sense.ascq << 8));
virtio_scsi_release(s);
}
}
static void virtio_scsi_pre_hotplug(HotplugHandler *hotplug_dev,
DeviceState *dev, Error **errp)
{
SCSIDevice *sd = SCSI_DEVICE(dev);
sd->hba_supports_iothread = true;
}
static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
SCSIDevice *sd = SCSI_DEVICE(dev);
AioContext *old_context;
int ret;
if (s->ctx && !s->dataplane_fenced) {
if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
return;
}
old_context = blk_get_aio_context(sd->conf.blk);
aio_context_acquire(old_context);
ret = blk_set_aio_context(sd->conf.blk, s->ctx, errp);
aio_context_release(old_context);
if (ret < 0) {
return;
}
}
if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
virtio_scsi_acquire(s);
virtio_scsi_push_event(s, sd,
VIRTIO_SCSI_T_TRANSPORT_RESET,
VIRTIO_SCSI_EVT_RESET_RESCAN);
scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
virtio_scsi_release(s);
}
}
static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
SCSIDevice *sd = SCSI_DEVICE(dev);
AioContext *ctx = s->ctx ?: qemu_get_aio_context();
if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
virtio_scsi_acquire(s);
virtio_scsi_push_event(s, sd,
VIRTIO_SCSI_T_TRANSPORT_RESET,
VIRTIO_SCSI_EVT_RESET_REMOVED);
scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
virtio_scsi_release(s);
}
aio_disable_external(ctx);
qdev_simple_device_unplug_cb(hotplug_dev, dev, errp);
aio_enable_external(ctx);
if (s->ctx) {
virtio_scsi_acquire(s);
/* If other users keep the BlockBackend in the iothread, that's ok */
blk_set_aio_context(sd->conf.blk, qemu_get_aio_context(), NULL);
virtio_scsi_release(s);
}
}
static struct SCSIBusInfo virtio_scsi_scsi_info = {
.tcq = true,
.max_channel = VIRTIO_SCSI_MAX_CHANNEL,
.max_target = VIRTIO_SCSI_MAX_TARGET,
.max_lun = VIRTIO_SCSI_MAX_LUN,
.complete = virtio_scsi_command_complete,
.fail = virtio_scsi_command_failed,
.cancel = virtio_scsi_request_cancelled,
.change = virtio_scsi_change,
.parse_cdb = virtio_scsi_parse_cdb,
.get_sg_list = virtio_scsi_get_sg_list,
.save_request = virtio_scsi_save_request,
.load_request = virtio_scsi_load_request,
};
void virtio_scsi_common_realize(DeviceState *dev,
VirtIOHandleOutput ctrl,
VirtIOHandleOutput evt,
VirtIOHandleOutput cmd,
Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev);
int i;
virtio_init(vdev, VIRTIO_ID_SCSI, sizeof(VirtIOSCSIConfig));
if (s->conf.num_queues == VIRTIO_SCSI_AUTO_NUM_QUEUES) {
s->conf.num_queues = 1;
}
if (s->conf.num_queues == 0 ||
s->conf.num_queues > VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED) {
error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
"must be a positive integer less than %d.",
s->conf.num_queues,
VIRTIO_QUEUE_MAX - VIRTIO_SCSI_VQ_NUM_FIXED);
virtio_cleanup(vdev);
return;
}
if (s->conf.virtqueue_size <= 2) {
error_setg(errp, "invalid virtqueue_size property (= %" PRIu32 "), "
"must be > 2", s->conf.virtqueue_size);
return;
}
s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues);
s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE;
s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE;
s->ctrl_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, ctrl);
s->event_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, evt);
for (i = 0; i < s->conf.num_queues; i++) {
s->cmd_vqs[i] = virtio_add_queue(vdev, s->conf.virtqueue_size, cmd);
}
}
static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOSCSI *s = VIRTIO_SCSI(dev);
Error *err = NULL;
QTAILQ_INIT(&s->tmf_bh_list);
virtio_scsi_common_realize(dev,
virtio_scsi_handle_ctrl,
virtio_scsi_handle_event,
virtio_scsi_handle_cmd,
&err);
if (err != NULL) {
error_propagate(errp, err);
return;
}
scsi_bus_init_named(&s->bus, sizeof(s->bus), dev,
&virtio_scsi_scsi_info, vdev->bus_name);
/* override default SCSI bus hotplug-handler, with virtio-scsi's one */
qbus_set_hotplug_handler(BUS(&s->bus), OBJECT(dev));
virtio_scsi_dataplane_setup(s, errp);
}
void virtio_scsi_common_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
int i;
virtio_delete_queue(vs->ctrl_vq);
virtio_delete_queue(vs->event_vq);
for (i = 0; i < vs->conf.num_queues; i++) {
virtio_delete_queue(vs->cmd_vqs[i]);
}
g_free(vs->cmd_vqs);
virtio_cleanup(vdev);
}
static void virtio_scsi_device_unrealize(DeviceState *dev)
{
VirtIOSCSI *s = VIRTIO_SCSI(dev);
virtio_scsi_reset_tmf_bh(s);
qbus_set_hotplug_handler(BUS(&s->bus), NULL);
virtio_scsi_common_unrealize(dev);
}
static Property virtio_scsi_properties[] = {
DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues,
VIRTIO_SCSI_AUTO_NUM_QUEUES),
DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
parent_obj.conf.virtqueue_size, 256),
DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
parent_obj.conf.seg_max_adjust, true),
DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors,
0xFFFF),
DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun,
128),
DEFINE_PROP_BIT("hotplug", VirtIOSCSI, host_features,
VIRTIO_SCSI_F_HOTPLUG, true),
DEFINE_PROP_BIT("param_change", VirtIOSCSI, host_features,
VIRTIO_SCSI_F_CHANGE, true),
DEFINE_PROP_LINK("iothread", VirtIOSCSI, parent_obj.conf.iothread,
TYPE_IOTHREAD, IOThread *),
DEFINE_PROP_END_OF_LIST(),
};
static const VMStateDescription vmstate_virtio_scsi = {
.name = "virtio-scsi",
.minimum_version_id = 1,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
};
static void virtio_scsi_common_class_init(ObjectClass *klass, void *data)
{
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
DeviceClass *dc = DEVICE_CLASS(klass);
vdc->get_config = virtio_scsi_get_config;
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
}
static void virtio_scsi_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
device_class_set_props(dc, virtio_scsi_properties);
dc->vmsd = &vmstate_virtio_scsi;
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
vdc->realize = virtio_scsi_device_realize;
vdc->unrealize = virtio_scsi_device_unrealize;
vdc->set_config = virtio_scsi_set_config;
vdc->get_features = virtio_scsi_get_features;
vdc->reset = virtio_scsi_reset;
vdc->start_ioeventfd = virtio_scsi_dataplane_start;
vdc->stop_ioeventfd = virtio_scsi_dataplane_stop;
hc->pre_plug = virtio_scsi_pre_hotplug;
hc->plug = virtio_scsi_hotplug;
hc->unplug = virtio_scsi_hotunplug;
}
static const TypeInfo virtio_scsi_common_info = {
.name = TYPE_VIRTIO_SCSI_COMMON,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VirtIOSCSICommon),
.abstract = true,
.class_init = virtio_scsi_common_class_init,
};
static const TypeInfo virtio_scsi_info = {
.name = TYPE_VIRTIO_SCSI,
.parent = TYPE_VIRTIO_SCSI_COMMON,
.instance_size = sizeof(VirtIOSCSI),
.class_init = virtio_scsi_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_HOTPLUG_HANDLER },
{ }
}
};
static void virtio_register_types(void)
{
type_register_static(&virtio_scsi_common_info);
type_register_static(&virtio_scsi_info);
}
type_init(virtio_register_types)
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