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

The name is shorter and clearer and more consistent with the name used
in virtio-scsi.

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

Signed-off-by: Asias He <asias.hejun@gmail.com>
[ penberg: keep comments vertically aligned ]
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>

bio is already signalled in all cases. No need to do it in destructor.

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>

It's better not to indent after the namespace specifier.

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

Change from blk::make_virtio_request to blk::make_request.

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

We are under the virtio namespace, it makes no sense to repeat the
virtio prefix again in the virito_blk driver.

Change the naming from virtio::virtio_blk to virtio::blk.

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

The lock used to protect _waiting_request_thread can go away.

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

Add Cloudius copyright and license statement to drivers/*.

A couple of header files were based on Linux's BSD-licensed header files
(e.g., include/uapi/linux/virtio_net.h) so they included the BSD license,
but not any copyright statement, so we can just replace that by our own
statement of the BSD license.

Instead of cancelling block requests due to no space on the ring
that lead to corruption of the upper layer, block until there is
space.

virtio_blk pre-allocates requests into a cache to avoid re-allocation
(possibly an unneeded optimization with the current allocator).  However,
it doesn't take into account that requests can be completed out-of-order,
and simply reuses requests in a cyclic order. Noted by Avi although
I had it made using a peak into the index ring but its too complex
solution. There is no performance degradation w/ smp due to the good
allocator we have today.

virtio-vring and it's users (net/blk) were changed so no request
header will be allocated on run time except for init. In order to
do that, I have to change get_buf and break it into multiple parts:

        // Get the top item from the used ring
        void* get_buf_elem(u32 *len);
        // Let the host know we consumed the used entry
        // We separate that from get_buf_elem so no one
        // will re-cycle the request header location until
        // we're finished with it in the upper layer
        void get_buf_finalize();
        // GC the used items that were already read to be emptied
        // within the ring. Should be called by add_buf
        // It was separated from the get_buf flow to allow parallelism of the two
        void get_buf_gc();

As a result, it was simple to get rid of the shared lock that protected
_avail_head variable before. Today only the thread that calls add_buf
updates this variable (add_buf calls get_buf_gc internally).

There are two new locks instead:
  - virtio-net tx_gc lock - very rarely it can be accessed
    by the tx_gc thread or normally by the tx xmit thread
  - virtio-blk make_requests - there are parallel requests

Trivial: Move code above, preparation for preventing past path allocations for the virtio request data

Move osv/bio.h into the .cc implementation and along with it move the virtio_blk_req structure that can be hidden from the header.

virtio_device is now a simple set of accessors around pci::device.  Since
the only users of virtio_device are virtio_driver and its subclasses, we
can simply fold it into virtio_driver, eliminating the middleman.

Resolves two FIXMEs where we leaked virtio_device objects created during
probing.

These are subsumed into the driver constructor/destrutor.

Driver enumeration requires instantiating a driver even for devices which
are not present; and if a device is present multiple times, we need to
pre-create multiple driver instances, which is awkward.  Further, driver
life-cycle is complicated, with separation between instantiation and binding
to a device.

Switch (back) to the traditional device-driven model, where we iterate over
all devices, try to find a matching driver factory, and when found, call it
to instantiate the driver and bind to the device.

Now it's possible to stress virtio through the external tests so
we do not need this code

Before we had 2 layes of calls, one in the virtio ring layer and
another in the virtio-blk layer. There wasn't any reall need for that.
The change allows the virtio-vring code to call a callback that the virtio-blk
registers and execute it directly.

and process pops requests from the ring.

In addition, implement the vfs device callbacks and wire them into virtio-blk
Need to test the later.

While it works, it needs to move to the virtio layer

several instances

afterwards issue a matching number of read request to verify the content.

Created abstract base classes for device and drivers, changed the flow of driver loading / device probing

a tests that uses it and adds plenty of block requests to the host.