eni_vdpa: add vDPA driver for Alibaba ENI

This patch adds a new vDPA driver for Alibaba ENI(Elastic Network
Interface) which is build upon virtio 0.9.5 specification.
And this driver is only enabled on X86 host currently.

Link: https://lore.kernel.org/r/6a9f32c00609af16bbb2ea32e633b3beb1cbf84b.1635493219.git.wuzongyong@linux.alibaba.com
Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211026083214.3375383-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de> # fix Kconfig typo
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/Kconfig

@@ -78,4 +78,12 @@ config VP_VDPA
 	help
 	  This kernel module bridges virtio PCI device to vDPA bus.
 
+config ALIBABA_ENI_VDPA
+	tristate "vDPA driver for Alibaba ENI"
+	select VIRTIO_PCI_LIB_LEGACY
+	depends on PCI_MSI && X86
+	help
+	  VDPA driver for Alibaba ENI (Elastic Network Interface) which is built upon
+	  virtio 0.9.5 specification.
+
 endif # VDPA

drivers/vdpa/Makefile

@@ -5,3 +5,4 @@ obj-$(CONFIG_VDPA_USER) += vdpa_user/
 obj-$(CONFIG_IFCVF)    += ifcvf/
 obj-$(CONFIG_MLX5_VDPA) += mlx5/
 obj-$(CONFIG_VP_VDPA)    += virtio_pci/
+obj-$(CONFIG_ALIBABA_ENI_VDPA) += alibaba/

drivers/vdpa/alibaba/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_ALIBABA_ENI_VDPA) += eni_vdpa.o
+