OpenE2K
/
qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity

virtio-scsi: convert virtio_scsi_bad_req() to use virtio_error() 

The virtio_scsi_bad_req() function is called when a guest sends a
request with missing or ill-sized headers. This generally happens
when the virtio_scsi_parse_req() function returns an error.

With this patch, virtio_scsi_bad_req() will mark the device as broken,
detach the request from the virtqueue and free it, instead of forcing
QEMU to exit.

In nearly all locations where virtio_scsi_bad_req() is called, the only
thing to do next is to return to the caller.

The virtio_scsi_handle_cmd_req_prepare() function is an exception though.

It is called in a loop by virtio_scsi_handle_cmd_vq() and passed requests
freshly popped from a cmd virtqueue; virtio_scsi_handle_cmd_req_prepare()
does some sanity checks on the request and returns a boolean flag to
indicate whether the request should be queued or not. In the latter case,
virtio_scsi_handle_cmd_req_prepare() has detected a non-fatal error and
sent a response back to the guest.

We have now a new condition to take into account: the device is broken
and should stop all processing.

The return value of virtio_scsi_handle_cmd_req_prepare() is hence changed
to an int. A return value of zero means that the request should be queued.
Other non-fatal error cases where the request shoudn't be queued  return
a negative errno (values are vaguely inspired by the error condition, but
the only goal here is to discriminate the case we're interested in).

And finally, if virtio_scsi_bad_req() was called, -EINVAL is returned. In
this case, virtio_scsi_handle_cmd_vq() detaches and frees already queued
requests, instead of submitting them.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Greg Kurz 2016-09-30 17:13:40 +02:00 committed by Michael S. Tsirkin
parent fa5e56c2a7
commit 661e32fb3c
1 changed files with 32 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
hw/scsi/virtio-scsi.c
View File

@ -81,10 +81,11 @@ static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
virtio_scsi_free_req(req);
}
static void virtio_scsi_bad_req(void)
static void virtio_scsi_bad_req(VirtIOSCSIReq *req)
{
error_report("wrong size for virtio-scsi headers");
exit(1);
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,
@ -387,7 +388,7 @@ static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
if (iov_to_buf(req->elem.out_sg, req->elem.out_num, 0,
&type, sizeof(type)) < sizeof(type)) {
virtio_scsi_bad_req();
virtio_scsi_bad_req(req);
return;
}
@ -395,7 +396,8 @@ static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
if (type == VIRTIO_SCSI_T_TMF) {
if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlTMFReq),
sizeof(VirtIOSCSICtrlTMFResp)) < 0) {
virtio_scsi_bad_req();
virtio_scsi_bad_req(req);
return;
} else {
r = virtio_scsi_do_tmf(s, req);
}
@ -404,7 +406,8 @@ static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
type == VIRTIO_SCSI_T_AN_SUBSCRIBE) {
if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICtrlANReq),
sizeof(VirtIOSCSICtrlANResp)) < 0) {
virtio_scsi_bad_req();
virtio_scsi_bad_req(req);
return;
} else {
req->resp.an.event_actual = 0;
req->resp.an.response = VIRTIO_SCSI_S_OK;
@ -521,7 +524,7 @@ static void virtio_scsi_fail_cmd_req(VirtIOSCSIReq *req)
virtio_scsi_complete_cmd_req(req);
}
static bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
static int virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req)
{
VirtIOSCSICommon *vs = &s->parent_obj;
SCSIDevice *d;
@ -532,17 +535,18 @@ static bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req
if (rc < 0) {
if (rc == -ENOTSUP) {
virtio_scsi_fail_cmd_req(req);
return -ENOTSUP;
} else {
virtio_scsi_bad_req();
virtio_scsi_bad_req(req);
return -EINVAL;
}
return false;
}
d = virtio_scsi_device_find(s, req->req.cmd.lun);
if (!d) {
req->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
virtio_scsi_complete_cmd_req(req);
return false;
return -ENOENT;
}
virtio_scsi_ctx_check(s, d);
req->sreq = scsi_req_new(d, req->req.cmd.tag,
@ -554,11 +558,11 @@ static bool virtio_scsi_handle_cmd_req_prepare(VirtIOSCSI *s, VirtIOSCSIReq *req
req->sreq->cmd.xfer > req->qsgl.size)) {
req->resp.cmd.response = VIRTIO_SCSI_S_OVERRUN;
virtio_scsi_complete_cmd_req(req);
return false;
return -ENOBUFS;
}
scsi_req_ref(req->sreq);
blk_io_plug(d->conf.blk);
return true;
return 0;
}
static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
@ -574,11 +578,24 @@ static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
{
VirtIOSCSIReq *req, *next;
int ret;
QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
while ((req = virtio_scsi_pop_req(s, vq))) {
if (virtio_scsi_handle_cmd_req_prepare(s, req)) {
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);
}
}
}
@ -708,7 +725,8 @@ void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
}
if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) {
virtio_scsi_bad_req();
virtio_scsi_bad_req(req);
goto out;
}
evt = &req->resp.event;