In vhost-user-blk, only WCE value can be set back to device in
guest kernel like
echo "write through" > /sys/block/vda/cache_type
So write_config() will only set WCE value from guest kernel to
vhost user side.
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Since config space in vhost-user-blk are mostly from backend
device, this change will get config space info from backend
by vhost-user protocol.
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
vhost-user-blk has better performance than virtio-blk, so we need
add vhost-user-blk support with SPDK in Rust-based VMMs.
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
