hv_sock: implements Hyper-V transport for Virtual Sockets (AF_VSOCK)

Hyper-V Sockets (hv_sock) supplies a byte-stream based communication
mechanism between the host and the guest. It uses VMBus ringbuffer as the
transportation layer.

With hv_sock, applications between the host (Windows 10, Windows Server
2016 or newer) and the guest can talk with each other using the traditional
socket APIs.

More info about Hyper-V Sockets is available here:

"Make your own integration services":
https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/user-guide/make-integration-service

The patch implements the necessary support in Linux guest by introducing a new
vsock transport for AF_VSOCK.

Signed-off-by: Dexuan Cui <[email protected]>
Cc: K. Y. Srinivasan <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Andy King <[email protected]>
Cc: Dmitry Torokhov <[email protected]>
Cc: George Zhang <[email protected]>
Cc: Jorgen Hansen <[email protected]>
Cc: Reilly Grant <[email protected]>
Cc: Asias He <[email protected]>
Cc: Stefan Hajnoczi <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: Cathy Avery <[email protected]>
Cc: Rolf Neugebauer <[email protected]>
Cc: Marcelo Cerri <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

MAINTAINERS

@@ -6286,6 +6286,7 @@ F:	drivers/net/hyperv/
 F:	drivers/scsi/storvsc_drv.c
 F:	drivers/uio/uio_hv_generic.c
 F:	drivers/video/fbdev/hyperv_fb.c
+F:	net/vmw_vsock/hyperv_transport.c
 F:	include/linux/hyperv.h
 F:	tools/hv/
 F:	Documentation/ABI/stable/sysfs-bus-vmbus

net/vmw_vsock/Kconfig

@@ -46,3 +46,15 @@ config VIRTIO_VSOCKETS_COMMON
 	  This option is selected by any driver which needs to access
 	  the virtio_vsock.  The module will be called
 	  vmw_vsock_virtio_transport_common.
+
+config HYPERV_VSOCKETS
+	tristate "Hyper-V transport for Virtual Sockets"
+	depends on VSOCKETS && HYPERV
+	help
+	  This module implements a Hyper-V transport for Virtual Sockets.
+
+	  Enable this transport if your Virtual Machine host supports Virtual
+	  Sockets over Hyper-V VMBus.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called hv_sock. If unsure, say N.

net/vmw_vsock/Makefile

@@ -2,6 +2,7 @@ obj-$(CONFIG_VSOCKETS) += vsock.o
 obj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o
 obj-$(CONFIG_VIRTIO_VSOCKETS) += vmw_vsock_virtio_transport.o
 obj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += vmw_vsock_virtio_transport_common.o
+obj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o
 
 vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o
 
@@ -11,3 +12,5 @@ vmw_vsock_vmci_transport-y += vmci_transport.o vmci_transport_notify.o \
 vmw_vsock_virtio_transport-y += virtio_transport.o
 
 vmw_vsock_virtio_transport_common-y += virtio_transport_common.o
+
+hv_sock-y += hyperv_transport.o