Merge tag 'kraxel-20220719-pull-request' of https://gitlab.com/kraxel/qemu into staging

ui: dbus-display fix, new gtk config options.
usb: xhci fix, doc updates.
microvm: no pcie io reservations.

# gpg: Signature made Tue 19 Jul 2022 16:21:06 BST
# gpg:                using RSA key A0328CFFB93A17A79901FE7D4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* tag 'kraxel-20220719-pull-request' of https://gitlab.com/kraxel/qemu:
  gtk: Add show_tabs=on|off command line option.
  usb: document pcap (aka usb traffic capture)
  usb: document guest-reset and guest-reset-all
  usb/hcd-xhci: check slotid in xhci_wakeup_endpoint()
  microvm: turn off io reservations for pcie root ports
  dbus-display: fix test race when initializing p2p connection

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/docs/system/devices/usb.rst b/docs/system/devices/usb.rst
index 872d916758..f39a88f080 100644
--- a/docs/system/devices/usb.rst
+++ b/docs/system/devices/usb.rst
@@ -353,3 +353,44 @@ and also assign it to the correct USB bus in QEMU like this:
         -device usb-ehci,id=ehci                             \\
         -device usb-host,bus=usb-bus.0,hostbus=3,hostport=1  \\
         -device usb-host,bus=ehci.0,hostbus=1,hostport=1
+
+``usb-host`` properties for reset behavior
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``guest-reset`` and ``guest-reset-all`` properties control
+whenever the guest is allowed to reset the physical usb device on the
+host.  There are three cases:
+
+``guest-reset=false``
+  The guest is not allowed to reset the (physical) usb device.
+
+``guest-reset=true,guest-resets-all=false``
+  The guest is allowed to reset the device when it is not yet
+  initialized (aka no usb bus address assigned).  Usually this results
+  in one guest reset being allowed.  This is the default behavior.
+
+``guest-reset=true,guest-resets-all=true``
+  The guest is allowed to reset the device as it pleases.
+
+The reason for this existing are broken usb devices.  In theory one
+should be able to reset (and re-initialize) usb devices at any time.
+In practice that may result in shitty usb device firmware crashing and
+the device not responding any more until you power-cycle (aka un-plug
+and re-plug) it.
+
+What works best pretty much depends on the behavior of the specific
+usb device at hand, so it's a trial-and-error game.  If the default
+doesn't work, try another option and see whenever the situation
+improves.
+
+record usb transfers
+^^^^^^^^^^^^^^^^^^^^
+
+All usb devices have support for recording the usb traffic.  This can
+be enabled using the ``pcap=<file>`` property, for example:
+
+``-device usb-mouse,pcap=mouse.pcap``
+
+The pcap files are compatible with the linux kernels usbmon.  Many
+tools, including ``wireshark``, can decode and inspect these trace
+files.