kernel: add vhost-net module

vhost-net is used to accelerate traffic to virtualisation
guests that use the virtio-net network card in QEMU.

Generally it is invoked by specifying "vhost=on" to a
QEMU -netdev device:

qemu-system-aarch64 -nographic -M virt -cpu host \
        --enable-kvm -bios u-boot.bin -smp 1 -m 2048 \
        -drive file=openwrt-armsr-armv8.img,format=raw,index=0,media=disk \
        -device "virtio-net,netdev=landev,disable-legacy=off,disable-modern=off" \
        -netdev "tap,id=landev,helper=/usr/lib/qemu-bridge-helper --br=br-lan,vhost=on"
Signed-off-by: NMathew McBride <matt@traverse.com.au>

package/kernel/linux/modules/virt.mk

@@ -117,3 +117,27 @@ define KernelPackage/vfio-pci/description
 endef
 
 $(eval $(call KernelPackage,vfio-pci))
+
+
+define KernelPackage/vhost
+  SUBMENU:=Virtualization
+  TITLE:=Host kernel accelerator for virtio (base)
+  KCONFIG:=CONFIG_VHOST
+  FILES:=$(LINUX_DIR)/drivers/vhost/vhost.ko \
+    $(LINUX_DIR)/drivers/vhost/vhost_iotlb.ko
+  AUTOLOAD:=$(call AutoProbe,vhost vhost_iotlb)
+endef
+
+$(eval $(call KernelPackage,vhost))
+
+
+define KernelPackage/vhost-net
+  SUBMENU:=Virtualization
+  TITLE:=Host kernel accelerator for virtio-net
+  DEPENDS:=+kmod-tun +kmod-vhost
+  KCONFIG:=CONFIG_VHOST_NET
+  FILES:=$(LINUX_DIR)/drivers/vhost/vhost_net.ko
+  AUTOLOAD:=$(call AutoProbe,vhost_net)
+endef
+
+$(eval $(call KernelPackage,vhost-net))