[V4,0/4] xen: privcmd: Add ioeventfd and fix irqfd support

Message

Viresh Kumar Oct. 16, 2023, 7:11 a.m. UTC

Hello,

Now that irqfd support (backend to guest interrupt) is already merged, this
series solves the other part of the problem, i.e. ioeventfd (guest to
backend interrupt).

More details inside the commits.

Arnd reported few issues with the ioctl macro usage and argument's layout, fixed
them for irqfd too, which was added recently.

--
Viresh

V3->V4:
- Use __u64 for indirect pointers in an ioctl command's arguments.
- Use u64_to_user_ptr() in kernel driver to access the same.
- Use _IOW() macro instead of the internal one: _IOC().

V2->V3:
- Remove explicit barriers and depend on spin lock instead to take care of it.
- Move check for empty ioeventfds list to privcmd_ioeventfd_deassign(), which
  could earlier call ioreq_free() even when the list wasn't empty and so we
  returned without printing a warning in v1 earlier. V2 implemented it
  incorrectly.

V1->V2:
- Increment irq_info refcnt only for valid info.
- Use u64 type for addr.
- Add comments for use of barriers.
- Use spin lock instead of mutex as we need to use them in irq handler.
- Add a warning when kioreq is getting freed and ioeventfds list isn't empty.
- Use struct_size().
- Validate number of vcpus as well.

Viresh Kumar (4):
  xen: Make struct privcmd_irqfd's layout architecture independent
  xen: irqfd: Use _IOW instead of the internal _IOC() macro
  xen: evtchn: Allow shared registration of IRQ handers
  xen: privcmd: Add support for ioeventfd

 drivers/xen/Kconfig               |   8 +-
 drivers/xen/events/events_base.c  |   3 +-
 drivers/xen/evtchn.c              |   2 +-
 drivers/xen/privcmd.c             | 407 +++++++++++++++++++++++++++++-
 include/uapi/xen/privcmd.h        |  22 +-
 include/xen/interface/hvm/ioreq.h |  51 ++++
 6 files changed, 482 insertions(+), 11 deletions(-)
 create mode 100644 include/xen/interface/hvm/ioreq.h