With pipelining it is possible to encounter a finished packet when cleaning
the queue due to a halt. This happens when a non stall error happens while
talking to a real device. In this case the queue on the usb-host side will
continue processing packets, and we can have completed packets waiting in
the queue after an error condition packet causing a halt.

There are 2 reasons to discard the completed packets at this point, rather
then trying to writing them back to the guest:

1) The guest expect to be able to cancel and/or change packets after the
packet with the error without doing an unlink, so writing them back may
confuse the guest.

2) Since the queue does not advance when halted, the writing back of these
packets will fail anyways since p->qtdaddr != q->qtdaddr, so the
ehci_verify_qtd call in ehci_writeback_async_complete_packet will fail.

Note that 2) means that then only functional change this patch introduces
is the printing of a warning when this scenario happens.

Note that discarding these packets means that the guest driver and the device
will get out of sync! This is unfortunate, but should not be a problem since
with a non stall error (iow an io-error) the 2 are out of sync already anyways.
Still this patch adds a warning to signal this happening.

Note that sofar this has only been seen with a DVB-T receiver, which gives
of a MPEG-2 stream, which allows for recovering from lost packets, see:
https://bugzilla.redhat.com/show_bug.cgi?id=890320Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

This patch adds support for usb3 streams to the usb subsystem core.
This is just adding a streams field / parameter in a number of places.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Coverity worries the EHCIQueue pointer could be null when we pass it
to functions that reference it.  The state machine ensures it can't be
null then.  Assert that, to hush the checker.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Some usb devices (host or network redirection) can benefit from knowing when
the guest stops using an endpoint. Redirection may involve submitting packets
independently from the guest (in combination with a fifo buffer between the
redirection code and the guest), to ensure that buffers of the real usb device
are timely emptied. This is done for example for isoc traffic and for interrupt
input endpoints. But when the (re)submission of packets is done by the device
code, then how does it know when to stop this?

For isoc endpoints this is handled by detecting a set interface (change alt
setting) command, which works well for isoc endpoints. But for interrupt
endpoints currently the redirection code never stops receiving data from
the device, which is less then ideal.

However the controller emulation is aware when a guest looses interest, as
then the qh for the endpoint gets unlinked (ehci, ohci, uhci) or the endpoint
is explicitly stopped (xhci). This patch adds a new ep_stopped USBDevice
method and modifies the hcd code to call this on queue unlink / ep stop.

This makes it possible for the redirection code to properly stop receiving
interrupt input (*) data when the guest no longer has interest in it.

*) And in the future also buffered bulk input.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ehci_raise_irq(s, USBSTS_PCD), gets applied immediately so there is no need
to call commit_irq after it.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

I tried lowering the time between raising an interrupt and rescanning the
async schedule to see if the guest has queued a new transfer before, but
that did not have any positive effect. I now believe the cause for this is
that lowering this time made it more likely to hit the 1 ms interrupt
threshold penalty for the next packet, as described in my
"ehci: Use uframe precision for interrupt threshold checking" commit.

Now that we do interrupt threshold handling with uframe precision, futher
lowering this time from .5 to .25 ms gives an extra 15% improvement in speed
(MB/s) reading from a simple USB-2.0 thumb-drive.

While at it also properly set the int_req_by_async flag for short packet
completions.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Before this patch, the following could happen:
1) Transfer completes, raises interrupt
2) .5 ms later we check if the guest has queued up any new transfers
3) We find and execute a new transfer
4) .2 ms later the new transfer completes
5) We re-run our frame_timer to write back the completion, but less then
   1 ms has passed since our last run, so frindex is not changed, so the
   interrupt threshold code delays the interrupt
6) 1 ms from the re-run our frame-timer runs again and finally delivers
   the interrupt

This leads to unnecessary large delays of interrupts, this code fixes this
by changing frindex to uframe precision and using that for interrupt threshold
control, making the interrupt fire at step 5 for guest which have low interrupt
threshold settings (like Linux).

Note that the guest still sees the frindex move in steps of 8 for migration
compatibility.

This boosts Linux read speed of a simple cheap USB thumb drive by 6 %.

Changes in v2:
-Make the guest see frindex move in steps of 8 by modifying ehci_opreg_read,
 rather then using a shadow variable
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ehci_fill_queue assumes that there is a one on one relationship between an ep
and a qh, this patch adds a check to ensure this.

Note I don't expect this to ever trigger, this is just something I noticed
the guest might do while working on other stuff. The only way this check can
trigger is if a guest mixes in and out qtd-s in a single qh for a non
control ep.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Remove the short-circuiting of fetchqtd in fetchqh, so that the
qtd gets properly verified before completing the transaction.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

No other changes.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

This is not allowed, except for clearing active on cancellation, so don't
warn when the new token does not have its active bit set.

This unifies the cancellation path for modified qtd-s, and prepares
ehci_verify_qtd to be used ad an extra check inside
ehci_writeback_async_complete_packet().
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Also drop the warning printf, which was there mainly because this was an
untested code path (as the previous bug fixes to it show), but that no
longer is the case now :)
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Lower the timer freq if no iso schedule packets complete for 64 frames in
a row.

We can safely do this, without adding latency, because:
1) If there is isoc traffic this will never trigger
2) For async handled interrupt packets (only usb-host), the completion handler
   will immediately schedule the frame_timer from a bh
3) All devices using NAK to signal no data for interrupt endpoints now use
   wakeup, which will immediately schedule the frame_timer from a bh

The advantage of this is that when we only have interrupt packets in the
periodic schedule, async_stepdown can do its work and significantly lower
the frequency at which the frame_timer runs.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Starting with commit 1c380f94 dma
transfers can actually fail.  This patch makes ehci keep track
of the busmaster bit in pci config space, by setting/clearing the
dma_context pointer.  Attempts to dma without context will result
in raising HSE (Host System Error) interrupt and stopping the host
controller.

This patch fixes WinXP not booting with a usb stick attached to ehci.
Root cause is seabios activating ehci so you can boot from the stick,
and WinXP clearing the busmaster bit before resetting the host
controller, leading to ehci actually trying dma while it is disabled.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

While testing the move to async packet handling for interrupt endpoints I
noticed that Windows-XP likes to play tricks with the next pointer for
periodic qh-s, so we should not fail qh / qtd verification when it changes.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Windows links interrupt qtd-s in circles, which means that when interrupt
endpoints return USB_RET_ASYNC, combined with the recent
"ehci: Retry to fill the queue while waiting for td completion" patch,
we keep adding the tds to the queue over and over again, as we detect the
circle from fill_queue, but we call it over and over again ...

This patch fixes this by changing the circle detection to also detect
circling into tds already queued up previously.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

This avoids the q->qtdaddr == p->qtdaddr asserts we have triggering, when
a queue contains multiple completed packages when we cancel the queue.

I triggered this with windows7 + async interrupt endpoint handling (*)
+ not detecting circles in ehci_fill_queue() properly, which makes the qtd
validation in ehci_fill_queue fail, causing cancellation of the queue on every
mouse event ...

*) Which is not going upstream as it will cause loss of interrupt events on
migration.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ehci_state_writeback() will free the packet, so we should not access
the packet after calling ehci_state_writeback().
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Instead make ehci_execute and ehci_fill_queue return the again value.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Since with the ehci and xhci controllers a single packet can be larger
then maxpacketsize, it is possible for the result of a single packet
to be both having transferred some data as well as the transfer to have
an error.

An example would be an input transfer from a bulk endpoint successfully
receiving 1 or more maxpacketsize packets from the device, followed
by a packet signalling halt.

While already touching all the devices and controllers handle_packet /
handle_data / handle_control code, also change the return type of
these functions to void, solely storing the status in the packet. To
make the code paths for regular versus async packet handling more
uniform.

This patch unfortunately is somewhat invasive, since makeing the qemu
usb core deal with this requires changes everywhere. This patch only
prepares the usb core for this, all the hcd / device changes are done
in such a way that there are no functional changes.

This patch has been tested with uhci and ehci hcds, together with usb-audio,
usb-hid and usb-storage devices, as well as with usb-redir redirection
with a wide variety of real devices.

Note that there is usually no need to directly set packet->actual_length
form devices handle_data callback, as that is done by usb_packet_copy()
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Guard against re-definition of EHCI_DEBUG. Allows for turning on of debug info
from configure (using --qemu-extra-cflags="-DEHCI_DEBUG=1") rather than source
code hacking.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Seperate the PCI stuff from the EHCI components. Extracted the PCIDevice
out into a new wrapper struct to make EHCIState non-PCI-specific. Seperated
tho non PCI init component out into a seperate "common" init function.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Pull the DMAContext for the PCI DMA out at device init time and put it into
the device state. Use dma_memory_read/write() instead of pci specific versions.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

The capabilities register and operational register offsets can vary from one
EHCI implementation to the next. Parameterise accordingly.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ehci was already testing for this, and we depend in various places
on no devices doing this, so lets move the check for this to the
usb core.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

After a short-not-ok packet ending short, we should not advance the queue.
Move enforcing this to the core, rather then handling it in the hcd code.

This may result in the queue now actually containing multiple input packets
(which would not happen before), and this requires special handling in
combination with pipelining, so disable pipleining for input endpoints
(for now).
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hcds which queue up more then one packet at once (uhci, ehci and xhci),
must clear the queue after an error which has caused the queue to halt.

Currently this is handled as a special case inside the hcd code, this
patch instead adds an USB_RET_REMOVE_FROM_QUEUE packet result code, teaches
the 3 hcds about this and moves the clearing of the queue on a halt into
the USB core.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

This can be used by usb-device code which wishes to process an entire endpoint
queue at once, to do this the usb-device code returns USB_RET_ADD_TO_QUEUE
from its handle_data class method and defines a flush_ep_queue class method
to call when the hcd is done queuing up packets.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

If the guest is using multiple transfers to try and keep the usb bus busy /
used at maximum efficiency, currently we would see / do the following:

1) submit transfer 1 to the device
2) submit transfer 2 to the device
3) report transfer 1 completion to guest
4) report transfer 2 completion to guest
5) submit transfer 1 to the device
6) report transfer 1 completion to guest
7) submit transfer 2 to the device
8) report transfer 2 completion to guest
etc.

So after the initial submission we would effectively only have 1 transfer
in flight, rather then 2. This is caused by us not checking the queue for
addition of new transfers by the guest (ie the resubmission of a recently
finished transfer), while waiting for a pending transfer to complete.
This patch does add a check for this, changing the sequence to:

1) submit transfer 1 to the device
2) submit transfer 2 to the device
3) report transfer 1 completion to guest
4) submit transfer 1 to the device
5) report transfer 2 completion to guest
6) submit transfer 2 to the device
etc.

Thus keeping 2 transfers in flight (most of the time, and always 1),
as intended by the guest.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

For ctrl endpoints Windows (atleast Win7) creates circular td lists, so far
these were not a problem because we would stop filling the queue if altnext
was set. Since further patches in this patchset remove the altnext check this
does become a problem and we need detection for going in circles.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Often the guest will queue up new packets in response to a packet, in the
async schedule with its IOC flag set, completing. By speeding up the
frame-timer, we notice these new packets earlier. This increases the
speed (MB/s) of a Linux guest reading from a USB mass storage device by a
factor of 1.15 on top of the "Improve latency of interrupt delivery"
speed-ups, both with and without input pipelining enabled.

I've not tested the speed-up of this patch without the
"Improve latency of interrupt delivery" patch.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

While doing various performance tests of reading from USB mass storage devices
I noticed the following::
1) When an async handled packet completes, we don't immediately report an
   interrupt to the guest, instead we wait for the frame-timer to run and
   report it from there
2) If 1) has been fixed and an async handled packet takes a while to complete,
   then async_stepdown will become a high value, which means that there
   will be a large latency before any new packets queued by the guest in
   response to the interrupt get seen

1) was done deliberately as part of commit f0ad01f9:
http://www.kraxel.org/cgit/qemu/commit/?h=usb.57&id=f0ad01f92ca02eee7cadbfd225c5de753ebd5fce
Since setting the interrupt immediately on async packet completion was causing
issues with Linux guests, I believe this recently fixed Linux bug explains
why this is happening:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=361aabf395e4a23cf554cf4ec0c0c6963b8beb01

Note that we can *not* count on this fix being present in all Linux guests!

I was hoping that the recently added support for Interrupt Threshold Control
would fix the issues with Linux guests, but adding a simple ehci_commit_irq()
call to ehci_async_bh() still caused problems with Linux guests.

The problem is, that when doing ehci_commit_irq() from ehci_async_bh(),
the "old" frindex value is used to calculate usbsts_frindex, and when
the frame-timer then runs possibly very shortly after ehci_async_bh(),
it increases the frame-timer, and thus any interrupts raised from that
frame-timer run, will also get reported to the guest immediately, rather
then being delayed to the next frame-timer run.

Luckily the solution for this is simple, this means that we need to
increase frindex before calling ehci_commit_irq() from ehci_async_bh(),
which in the end boils down to simple calling ehci_frame_timer() instead
of ehci_async_bh() from the bh.

This may seem like it causes a lot of extra work to be done, but this
is not true. Any work done from the frame-timer processing the periodic
schedule is work which then does not need to be done the next time the
frame timer runs, also the frame-timer will re-arm itself at (possibly)
a later time then it was armed for saving a vmexit at that time.

As an additional advantage moving to simply calling the frame-timer also
fixes 2) as the packet completion will set async_stepdown to 0, and the
re-arming of the timer with an async_stepdown of 0 ensures that any
newly queued up packets get seen in a reasonable amount of time.

This improves the speed (MB/s) of a Linux guest reading from a USB mass
storage device by a factor of 1.5 - 1.7 with input pipelining disabled,
and by a factor of 1.8 with input pipelining enabled.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

According to 4.15.1.2 an interrupt must be raised when a short packet
is received. If we don't do this it may take a significant time for
the guest to notice a short trasnfer has completed, since only the last td
will have its IOC flag set, and a short transfer may complete in an earlier
packet.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>