When a total ordering between multiple atomic variables is not required
then use Ordering::Acquire with atomic loads and Ordering::Release with
atomic stores.
This will improve performance as this does not require a memory fence
on x86_64 which Ordering::SeqCst will use.
Add a comment to the code in the vCPU handling code where it operates on
multiple atomics to explain why Ordering::SeqCst is required.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
The Windows virtio block driver puts multiple data descriptors between
the header and the status footer. To handle this when parsing iterate
over the descriptor chain until the end is reached accumulating the
address and length pairs in a vector. For execution iterate over the
vector and make sequential reads from the disk for each data descriptor.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
In order to simplify the transition to VirtioCommon and to avoid needing
to set empty fields derive Default for VirtioCommon.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
There will be some cases where the implementation of the snapshot()
function from the Snapshottable trait will require to modify some
internal data, therefore we make this possible by updating the trait
definition with snapshot(&mut self).
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
As we never join the spawned virtio-devices worker threads, the error
returned from each worker thread is lost. For now, we simply print out
the error from each worker thread.
Fixes: #1551
Signed-off-by: Bo Chen <chen.bo@intel.com>
Using the Rust Barrier mechanism, this patch forces each virtio device
to acknowledge they've been correctly paused before going further.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Instead of passing only the event type through the handle_event()
callback, we make the trait slightly more generic by providing the
epoll event to each virtio device implementation.
This is particularly useful for vsock as it will need the event set.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Instead of just logging error messages but continue the processing of
the queues, this patch returns errors right away. This allows for a
quicker detection of an error happening on the virtqueue.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This introduces a new version of virtio-blk device. The default
virtio-blk provides synchronous processing of the queues, while this
new version relies on io_uring from the host kernel to provide an
asynchronous processing of the queues.
This new asynchronous version provides a huge performance improvement
compared to the default synchronous version.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
