[Qemu-devel] vhost-user:add VHOST_USER_CLEAR_MEM_TABLE

[Linhaifeng]

I want to add this message for vhost-user backend's memory changed.Any 
suggestion?

 * VHOST_USER_CLEAR_MEM_TABLE
      Id: 15
      Equivalent ioctl: VHOST_USER_CLEAR_MEM_TABLE
      Master payload: u64
      Clear the memory regions on the slave when the memory of the forward 
freed.e.g.when unplug the vhost-user device or reload the virio-net driver.
      Bits (0-7) of the payload contain nothing.