We now print disk probe information like:

virtio-scsi: Add scsi device target=1, lun=0   as vblk0, devsize=10842275840

Disable it by default. The --verbose option will make this info
available which is useful when debug.

Reported-by: Pekka Enberg <penberg@cloudius-systems.com>
Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Set req->cdb_len to the actual size of the scsi command and only copy
the actual size of the command.

This reduces the number of bytes we copy.

This also fixes the warning in pvscsi which complains the size of the
cdb is larger than expected.

Signed-off-by: Asias He <asias@cloudius-systems.com>

This is used to tell lower-level scsi driver to free the request,
otherwise the scsi layer will free the request.

read/write/flush scsi are async request, they are freed by the
lower-level scsi driver. Other scsi request are freed by the scsi layer.

Signed-off-by: Asias He <asias@cloudius-systems.com>

This eliminates duplicated code in make_request() of scsi driver.

Signed-off-by: Asias He <asias@cloudius-systems.com>

Use this to limit max number of target to scan.

Signed-off-by: Asias He <asias@cloudius-systems.com>

req->response can be not zero when in some cases, for instance, when the
REPORT LUNS command send to a target which does not exist. Pass the
handling of req->response to command handling.

This allows us to probe multiple targets.

Signed-off-by: Asias He <asias@cloudius-systems.com>

Split the common scsi code from virtio-scsi.cc to scsi-common.cc. This way, we can share
code with other scsi driver, e.g., vmw-pvscsi.

Tested on local kvm and GCE.

Signed-off-by: Asias He <asias@cloudius-systems.com>

Signed-off-by: Zhi Yong Wu <zwu.kernel@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Currently we only support scan one target. We scan target 0 by
default.  On GCE, the default target is 1. Let's scan scan target 1.

Signed-off-by: Asias He <asias@cloudius-systems.com>

We already copied req->resp.cmd.response into response. Use the shorter
one.

Signed-off-by: Asias He <asias@cloudius-systems.com>

GCE does not support REPORT LUNS, fallback to TEST_UNIT_READY to scan
luns.

Signed-off-by: Asias He <asias@cloudius-systems.com>

virtio-scsi device can not handle a request of an infinite size. It
reports max_sectors in the config space. Respect it by using
multiplex_strategy and dev->max_io_size to limit max request size.
multiplex_strategy works by splitting large bios into multiple smaller
bios.

Signed-off-by: Asias He <asias@cloudius-systems.com>

msi interrupt is not always implemented. Fallback to gsi interrupt when
msi interrupt is not available.

Signed-off-by: Asias He <asias@cloudius-systems.com>

Signed-off-by: Takuya ASADA <syuu@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

The check is moved to bdev_read and bdev_write.

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

With indirect descriptor, we can queue more buffers in the queue.
Indirect descriptor helps block device by making the large request does
not consume the entire ring and making the queue depth deeper. Indirect
descriptor does not help net device because it makes the queue longer so
it adds latency. The tests show that indirect descriptor makes blk
faster and there is no real measurable degradation on net. Also the
indirect will turn on only when we are short of descriptors.

This patch only enables indirect descriptor for vblk and vscsi. vnet is
not enabled.

1) vblk
Before: 340MB/s
After:  350MB/s

2) vscsi
Before: 320MB/s
After:  410MB/s

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Now, virtio-scsi disks use the same name as virtio-blk, e.g., vblk0,
vlbk1. If both scsi and blk are added to guest, they share the global disk
index number.

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

This adds initial virtio-scsi support. We have no scsi layer in osv, in
this implementation virtio-scsi works directly with the bio layer. It
translates BIO_READ, BIO_WRITE and BIO_FLUSH to SCSI CMD.

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>