xen: add pvUSB backend

Add a backend for para-virtualized USB devices for xen domains.

The backend is using host-libusb to forward USB requests from a
domain via libusb to the real device(s) passed through.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Message-id: 1463062421-613-4-git-send-email-jgross@suse.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/usb/Makefile.objs

@@ -38,3 +38,7 @@ common-obj-$(CONFIG_USB_REDIR) += redirect.o quirks.o
 
 # usb pass-through
 common-obj-y += $(patsubst %,host-%.o,$(HOST_USB))
+
+ifeq ($(CONFIG_USB_LIBUSB),y)
+common-obj-$(CONFIG_XEN_BACKEND) += xen-usb.o
+endif

hw/xenpv/xen_machine_pv.c

@@ -80,6 +80,9 @@ static void xen_init_pv(MachineState *machine)
     xen_be_register("vfb", &xen_framebuffer_ops);
     xen_be_register("qdisk", &xen_blkdev_ops);
     xen_be_register("qnic", &xen_netdev_ops);
+#ifdef CONFIG_USB_LIBUSB
+    xen_be_register("qusb", &xen_usb_ops);
+#endif
 
     /* configure framebuffer */
     if (xenfb_enabled) {

include/hw/xen/xen_backend.h

@@ -101,6 +101,9 @@ extern struct XenDevOps xen_kbdmouse_ops;     /* xen_framebuffer.c */
 extern struct XenDevOps xen_framebuffer_ops;  /* xen_framebuffer.c */
 extern struct XenDevOps xen_blkdev_ops;       /* xen_disk.c        */
 extern struct XenDevOps xen_netdev_ops;       /* xen_nic.c         */
+#ifdef CONFIG_USB_LIBUSB
+extern struct XenDevOps xen_usb_ops;          /* xen-usb.c         */
+#endif
 
 void xen_init_display(int domid);
 

include/hw/xen/xen_common.h

@@ -49,6 +49,8 @@ typedef xc_gnttab xengnttab_handle;
 #define xengnttab_unmap(h, a, n) xc_gnttab_munmap(h, a, n)
 #define xengnttab_map_grant_refs(h, c, d, r, p) \
     xc_gnttab_map_grant_refs(h, c, d, r, p)
+#define xengnttab_map_domain_grant_refs(h, c, d, r, p) \
+    xc_gnttab_map_domain_grant_refs(h, c, d, r, p)
 
 #define xenforeignmemory_open(l, f) xen_xc