[v6,0/3] xen, usb: support pvUSB frontend driver

Message

Jürgen Groß Oct. 13, 2021, 7:52 a.m. UTC

This series adds XEN guest pvUSB support. With pvUSB it is possible to
use physical USB devices from a XEN domain.

Since V4 a lot of time (several years) has passed. This is a revived
attempt to get the frontend into the kernel.

The support consists of a frontend in form of a virtual hcd driver in
the unprivileged domU passing I/O-requests to the backend in a driver
domain (usually Dom0). The backend is not part of this patch series,
as it is supported via qemu.

The code is taken (and adapted) from the original pvUSB implementation
done for Linux 2.6 in 2008 by Fujitsu.

Normal operation of USB devices by adding and removing them dynamically
to/from a domain has been tested using various USB devices (USB 1.1,
2.0 and 3.0) using the qemu based backend.

Changes in V6:
- add SPDX line to driver

Changes in V5:
- added interface documentation to patch 1
- frontend no longer trusts backend to return only sane values

Changes in V4:
- remove sysfs file from frontend, as it violated the "one value per file"
  rule and didn't serve any real purpose.

Changes in V3:
- move frontend to drivers/usb/host and rename it to xen-hcd.
- changed name prefixes in patch 1 to "xenusb" as requested by Greg
- use __u<n> types rather than uint<n>_t as requested by Greg

Changes in V2:
- removed backend, as it can be implemented in user land
- added some access macros and definitions to the pvUSB interface
  description to make it independant from linux kernel USB internals
- adapted frontend to newer kernel version and use new pvUSB
  interface macros
- set port status in one chunk as suggested by Oliver Neukum

Juergen Gross (3):
  usb: Add Xen pvUSB protocol description
  usb: Introduce Xen pvUSB frontend (xen hcd)
  xen: add Xen pvUSB maintainer

 MAINTAINERS                      |    8 +
 drivers/usb/host/Kconfig         |   11 +
 drivers/usb/host/Makefile        |    1 +
 drivers/usb/host/xen-hcd.c       | 1606 ++++++++++++++++++++++++++++++
 include/xen/interface/io/usbif.h |  421 ++++++++
 5 files changed, 2047 insertions(+)
 create mode 100644 drivers/usb/host/xen-hcd.c
 create mode 100644 include/xen/interface/io/usbif.h