587a420429
We need to rely on the latest kvm-ioctls version to benefit from the recent addition of unregister_ioevent(), allowing us to detach a previously registered eventfd to a PIO or MMIO guest address. Because of this update, we had to modify the current constraint we had on the vmm-sys-util crate, using ">= 0.1.1" instead of being strictly tied to "0.2.0". Once the dependency conflict resolved, this commit took care of fixing build issues caused by recent modification of kvm-ioctls relying on EventFd reference instead of RawFd. Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com> |
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README.md |
vHost
A crate to support vhost backend drivers for virtio devices.
Kernel-based vHost Backend Drivers
The vhost drivers in Linux provide in-kernel virtio device emulation. Normally the hypervisor userspace process emulates I/O accesses from the guest. Vhost puts virtio emulation code into the kernel, taking hypervisor userspace out of the picture. This allows device emulation code to directly call into kernel subsystems instead of performing system calls from userspace. The hypervisor relies on ioctl based interfaces to control those in-kernel vhost drivers, such as vhost-net, vhost-scsi and vhost-vsock etc.
vHost-user Backend Drivers
The vhost-user protocol is aiming to implement vhost backend drivers in userspace, which complements the ioctl interface used to control the vhost implementation in the Linux kernel. It implements the control plane needed to establish virtqueue sharing with a user space process on the same host. It uses communication over a Unix domain socket to share file descriptors in the ancillary data of the message.
The protocol defines two sides of the communication, master and slave. Master is the application that shares its virtqueues, slave is the consumer of the virtqueues. Master and slave can be either a client (i.e. connecting) or server (listening) in the socket communication.