vhost-user-blk: add vhost-user-blk-pci host device to Qemu

Add a new vhost-user device type "vhost-user-blk-pci" to
accelerate virtio-blk processing in user space. Qemu uses a
char device to communicate with the I/O processing backend.

The feature is enabled by default with Linux, and depends on
CONFIG_VIRTIO configuration. To use this feature users can
start the qemu with the following command line like this:

qemu-system-x86_64 -m 1024 -object memory-backend-file, \
id=mem,size=1G, mem-path=/dev/hugepages,share=on \
-numa node,memdev=mem -hda /root/ubuntu.img \
-chardev socket,id=char0,path=/path/vhost.0 \
-net user,hostfwd=tcp::10022-:22 -net nic \
-device vhost-user-blk-pci,chardev=char0,\
logical_block_size=512,size=20G \
-vnc 0.0.0.0:1 --enable-kvm

For 'size' parameter, users can specify with G(GiB) or M(MiB).

Change-Id: I18b7ee930d07c6d9cb051a50398965a37a1c402b
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-on: https://review.gerrithub.io/363361
Reviewed-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Tested-by: Daniel Verkamp <daniel.verkamp@intel.com>

configure

@@ -226,6 +226,7 @@ xfs=""
 
 vhost_net="no"
 vhost_scsi="no"
+vhost_user_blk="no"
 vhost_vsock="no"
 kvm="no"
 hax="no"
@@ -681,6 +682,7 @@ Haiku)
   kvm="yes"
   vhost_net="yes"
   vhost_scsi="yes"
+  vhost_user_blk="yes"
   vhost_vsock="yes"
   QEMU_INCLUDES="-I\$(SRC_PATH)/linux-headers -I$(pwd)/linux-headers $QEMU_INCLUDES"
 ;;
@@ -1027,6 +1029,10 @@ for opt do
   ;;
   --enable-vhost-scsi) vhost_scsi="yes"
   ;;
+  --disable-vhost-user-blk) vhost_user_blk="no"
+  ;;
+  --enable-vhost-user-blk) vhost_user_blk="yes"
+  ;;
   --disable-vhost-vsock) vhost_vsock="no"
   ;;
   --enable-vhost-vsock) vhost_vsock="yes"
@@ -1382,6 +1388,7 @@ disabled with --disable-FEATURE, default is enabled if available:
   cap-ng          libcap-ng support
   attr            attr and xattr support
   vhost-net       vhost-net acceleration support
+  vhost-user-blk  VM virtio-blk acceleration in user space
   spice           spice
   rbd             rados block device (rbd)
   libiscsi        iscsi support
@@ -5076,6 +5083,7 @@ echo "posix_madvise     $posix_madvise"
 echo "libcap-ng support $cap_ng"
 echo "vhost-net support $vhost_net"
 echo "vhost-scsi support $vhost_scsi"
+echo "vhost-user-blk support $vhost_user_blk"
 echo "vhost-vsock support $vhost_vsock"
 echo "Trace backends    $trace_backends"
 if have_backend "simple"; then
@@ -5464,6 +5472,9 @@ fi
 if test "$vhost_scsi" = "yes" ; then
   echo "CONFIG_VHOST_SCSI=y" >> $config_host_mak
 fi
+if test "$vhost_user_blk" = "yes" ; then
+  echo "CONFIG_VHOST_USER_BLK=y" >> $config_host_mak
+fi
 if test "$vhost_net" = "yes" ; then
   echo "CONFIG_VHOST_NET_USED=y" >> $config_host_mak
 fi

hw/block/Makefile.objs

@@ -13,3 +13,6 @@ obj-$(CONFIG_SH4) += tc58128.o
 
 obj-$(CONFIG_VIRTIO) += virtio-blk.o
 obj-$(CONFIG_VIRTIO) += dataplane/
+ifeq ($(CONFIG_VIRTIO),y)
+obj-$(CONFIG_VHOST_USER_BLK) += vhost-user-blk.o
+endif