• Tiwei Bie's avatar
    vhost: introduce vDPA-based backend · 4c8cf318
    Tiwei Bie authored
    This patch introduces a vDPA-based vhost backend. This backend is
    built on top of the same interface defined in virtio-vDPA and provides
    a generic vhost interface for userspace to accelerate the virtio
    devices in guest.
    
    This backend is implemented as a vDPA device driver on top of the same
    ops used in virtio-vDPA. It will create char device entry named
    vhost-vdpa-$index for userspace to use. Userspace can use vhost ioctls
    on top of this char device to setup the backend.
    
    Vhost ioctls are extended to make it type agnostic and behave like a
    virtio device, this help to eliminate type specific API like what
    vhost_net/scsi/vsock did:
    
    - VHOST_VDPA_GET_DEVICE_ID: get the virtio device ID which is defined
      by virtio specification to differ from different type of devices
    - VHOST_VDPA_GET_VRING_NUM: get the maximum size of virtqueue
      supported by the vDPA device
    - VHSOT_VDPA_SET/GET_STATUS: set and get virtio status of vDPA device
    - VHOST_VDPA_SET/GET_CONFIG: access virtio config space
    - VHOST_VDPA_SET_VRING_ENABLE: enable a specific virtqueue
    
    For memory mapping, IOTLB API is mandated for vhost-vDPA which means
    userspace drivers are required to use
    VHOST_IOTLB_UPDATE/VHOST_IOTLB_INVALIDATE to add or remove mapping for
    a specific userspace memory region.
    
    The vhost-vDPA API is designed to be type agnostic, but it allows net
    device only in current stage. Due to the lacking of control virtqueue
    support, some features were filter out by vhost-vdpa.
    
    We will enable more features and devices in the near future.
    Signed-off-by: default avatarTiwei Bie <tiwei.bie@intel.com>
    Signed-off-by: default avatarEugenio Pérez <eperezma@redhat.com>
    Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
    Link: https://lore.kernel.org/r/20200326140125.19794-8-jasowang@redhat.comSigned-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
    4c8cf318
Makefile 433 Bytes