• Xie Yongji's avatar
    vduse: Introduce VDUSE - vDPA Device in Userspace · c8a6153b
    Xie Yongji authored
    This VDUSE driver enables implementing software-emulated vDPA
    devices in userspace. The vDPA device is created by
    ioctl(VDUSE_CREATE_DEV) on /dev/vduse/control. Then a char device
    interface (/dev/vduse/$NAME) is exported to userspace for device
    emulation.
    
    In order to make the device emulation more secure, the device's
    control path is handled in kernel. A message mechnism is introduced
    to forward some dataplane related control messages to userspace.
    
    And in the data path, the DMA buffer will be mapped into userspace
    address space through different ways depending on the vDPA bus to
    which the vDPA device is attached. In virtio-vdpa case, the MMU-based
    software IOTLB is used to achieve that. And in vhost-vdpa case, the
    DMA buffer is reside in a userspace memory region which can be shared
    to the VDUSE userspace processs via transferring the shmfd.
    
    For more details on VDUSE design and usage, please see the follow-on
    Documentation commit.
    
    NB(mst): when merging this with
    b542e383 ("eventfd: Make signal recursion protection a task bit")
    replace eventfd_signal_count with eventfd_signal_allowed,
    and drop the previous
    ("eventfd: Export eventfd_wake_count to modules").
    Signed-off-by: default avatarXie Yongji <xieyongji@bytedance.com>
    Acked-by: default avatarJason Wang <jasowang@redhat.com>
    Link: https://lore.kernel.org/r/20210831103634.33-13-xieyongji@bytedance.comSigned-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
    c8a6153b
Makefile 244 Bytes