Following the refactoring of the code allowing multiple threads to
access the same instance of the guest memory, this patch goes one step
further by adding RwLock to it. This anticipates the future need for
being able to modify the content of the guest memory at runtime.
The reasons for adding regions to an existing guest memory could be:
- Add virtio-pmem and virtio-fs regions after the guest memory was
created.
- Support future hotplug of devices, memory, or anything that would
require more memory at runtime.
Because most of the time, the lock will be taken as read only, using
RwLock instead of Mutex is the right approach.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The VMM guest memory was cloned (copied) everywhere the code needed to
have ownership of it. In order to clean the code, and in anticipation
for future support of modifying this guest memory instance at runtime,
it is important that every part of the code share the same instance.
Because VirtioDevice implementations need to have access to it from
different threads, that's why Arc must be used in this case.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The structure of the vmm-sys-util crate has changed with lots of code
moving to submodules.
This change adjusts the use of the imported structs to reference the
submodules.
Fixes: #145
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
The existing code taking care of the epoll loop was too restrictive as
it was propagating the error returned from the epoll_wait() syscall, no
matter what was the error. This causes the epoll loop to be broken,
leading to a non-functional virtio device.
This patch enforces the parsing of the returned error and prevent from
the error propagation in case it is EINTR, which stands for Interrupted.
In case the epoll loop is interrupted, it is appropriate to retry.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
As per the VIRTIO specification, every virtio device configuration can
be updated while the guest is running. The guest needs to be notified
when this happens, and it can be done in two different ways, depending
on the type of interrupt being used for those devices.
In case the device uses INTx, the allocated IRQ pin is shared between
queues and configuration updates. The way for the guest to differentiate
between an interrupt meant for a virtqueue or meant for a configuration
update is tied to the value of the ISR status field. This field is a
simple 32 bits bitmask where only bit 0 and 1 can be changed, the rest
is reserved.
In case the device uses MSI/MSI-X, the driver should allocate a
dedicated vector for configuration updates. This case is much simpler as
it only requires the device to send the appropriate MSI vector.
The cloud-hypervisor codebase was not supporting the update of a virtio
device configuration. This patch extends the existing VirtioInterrupt
closure to accept a type that can be Config or Queue, so that based on
this type, the closure implementation can make the right choice about
which interrupt pin or vector to trigger.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit introduces the implementation of the virtio-pmem device
based on the pending proposal of the virtio specification here:
https://lists.oasis-open.org/archives/virtio-dev/201903/msg00083.html
It is also based on the kernel patches coming along with the virtio
proposal: https://lkml.org/lkml/2019/6/12/624
And it is based off of the current crosvm implementation found in
devices/src/virtio/pmem.rs relying on commit
bb340d9a94d48514cbe310d05e1ce539aae31264
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
