The net/socket.c net client is not truly asynchronous.  This patch
borrows the qemu_set_fd_handler2() code from net/tap.c as the basis for
proper asynchronous send/receive.

Only read packets from the socket when the peer is able to receive.
This avoids needless queuing.

Later patches implement asynchronous send.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

In commit 60c07d93 ("net: fix
qemu_can_send_packet logic") the "VLAN" broadcast behavior was changed
to queue packets if any net client cannot receive.  It turns out that
this was not actually the right fix and just hides the real bug that
hw/usb/dev-network.c:usbnet_receive() clobbers its receive buffer when
called multiple times in a row.  The commit also introduced a new bug
that "VLAN" packets would not be sent if one of multiple net clients was
down.

The hw/usb/dev-network.c bug has since been fixed, so this patch reverts
broadcast behavior to send packets as long as one net client can
receive.  Packets simply get queued for the net clients that are
temporarily unable to receive.
Reported-by: NRoy.Li <rongqing.li@windriver.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

The USB network interface has a single buffer which the guest reads
from.  This patch prevents multiple calls to usbnet_receive() from
clobbering the input buffer.  Instead we queue packets until buffer
space becomes available again.

This is inspired by virtio-net and e1000 rxbuf handling.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

The USB network interface has two code paths depending on whether or not
RNDIS mode is enabled.  Refactor usbnet_receive() so that there is a
common path throughout the function instead of duplicating everything
across if (is_rndis(s)) ... else ... code paths.

Clean up coding style and 80 character line wrap along the way.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

Document the -netdev syntax which supercedes the older -net syntax.
This patch is a first step to making -netdev prominent in the QEMU
manual.
Reported-by: NAnatoly Techtonik <techtonik@gmail.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

Net send functions have a return value where 0 means the packet has not
been sent and will be queued.  A non-zero value means the packet was
sent or an error caused the packet to be dropped.

This patch fixes two instances where packets are queued but we return
their size.  This causes callers to believe the packets were sent.  When
the caller uses the async send interface this creates a real problem
because the callback will be invoked for a packet that the caller
believed to be already sent.  This bug can cause double-frees in the
caller.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

This patch adds the missing NetClient->receive_disabled logic in the
sendv delivery code path.  It seems that commit
893379ef ("net: disable receiving if
client returns zero") only added the logic to qemu_deliver_packet() and
not qemu_deliver_packet_iov().

The receive_disabled flag should be automatically set when .receive(),
.receive_raw(), or .receive_iov() return 0.  No further packets will be
delivered to the NetClient until the receive_disabled flag is cleared
again by calling qemu_flush_queued_packets().

Typically the NetClient will wait until its file descriptor becomes
writable and then invoke qemu_flush_queued_packets() to resume
transmission.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

This is reported by QA. When installing os with pxe, after the initial
kernel and initrd are loaded, the procedure tries to copy files from install
server to local harddisk, the network becomes stall because of running out of
receive descriptor.

[Whitespace fixes and removed qemu_notify_event() because Paolo's
earlier net patches have moved it into qemu_flush_queued_packets().

Additional info:

I can reproduce the network hang with a tap device doing a iPXE HTTP
boot as follows:

  $ qemu -enable-kvm -m 1024 \
    -netdev tap,id=netdev0,script=no,downscript=no \
    -device i82559er,netdev=netdev0,romfile=80861209.rom \
    -drive if=virtio,cache=none,file=test.img
  iPXE> ifopen net0
  iPXE> config # set static network configuration
  iPXE> kernel http://mirror.bytemark.co.uk/fedora/linux/releases/17/Fedora/x86_64/os/images/pxeboot/vmlinuz

I needed a vanilla iPXE ROM to get to the iPXE prompt.  I think the boot
prompt has been disabled in the ROMs that ship with QEMU to reduce boot
time.

During the vmlinuz HTTP download there is a network hang.  hw/eepro100.c
has reached the end of the rx descriptor list.  When the iPXE driver
replenishes the rx descriptor list we don't kick the QEMU net subsystem
and event loop, thereby leaving the tap netdev without its file
descriptor in select(2).

Stefan Hajnoczi <stefanha@gmail.com>]
Signed-off-by: NBo Yang <boyang@suse.com>
Signed-off-by: NStefan Hajnoczi <stefanha@gmail.com>

xen does not have a register that, when written, will cause can_receive
to go from false to true.  However, flushing the queue can be attempted
whenever the front-end raises its side of the Xen event channel.  There
is a single event channel for tx and rx.

Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

When the guests replenish the receive ring buffer, the network device
should flush its queue of pending packets.  This is done with
qemu_flush_queued_packets.

e1000's can_receive can go from false to true when RCTL or RDT are
modified.
Reported-by: NLuigi Rizzo <rizzo@iet.unipi.it>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Jan Kiszka <jan.kiszka@siemens.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

virtio-net has code to flush the queue and notify the iothread
whenever new receive buffers are added by the guest.  That is
fine, and indeed we need to do the same in all other drivers.
However, notifying the iothread should be work for the network
subsystem.  And since we are at it we can add a little smartness:
if some of the queued packets already could not be delivered,
there is no need to notify the iothread.
Reported-by: NLuigi Rizzo <rizzo@iet.unipi.it>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Jan Kiszka <jan.kiszka@siemens.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

* 'usb.64' of git://git.kraxel.org/qemu: (54 commits)
  xhci: allow bytewise capability register reads
  xhci: kill xhci_mem_{read,write} dispatcher functions
  xhci: support multiple interrupters
  xhci: pick target interrupter
  xhci: prepare xhci_runtime_{read,write} for multiple interrupters
  xhci: add XHCIInterrupter
  xhci: move register update into xhci_intr_raise
  xhci: add msix support
  xhci: rework interrupt handling
  xhci: fix & cleanup msi.
  usb-storage: usb3 support
  usb3: bos decriptor
  usb3: superspeed endpoint companion
  usb3: superspeed descriptors
  xhci: update port handling
  xhci: update register layout
  xhci: fix runtime write tracepoint
  xhci: add trace_usb_xhci_ep_set_dequeue
  xhci: trace cc codes in cleartext
  xhci: iso xfer support
  ...

optimizer.c contains some cases were the break is appearing in both the
if and the else parts. Fix that by moving it to the outer part. Also
move some common code there.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

brcond and setcond ops are not commutative, but it's easy to compute the
new condition after swapping the arguments. Try to always put the constant
argument in second position like for commutative ops, to help backends to
generate better code.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

shift/rot r, 0, a is equivalent to movi r, 0.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

and r, a, 0 is equivalent to a movi r, 0.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

or/xor r, a, 0 is equivalent to a mov r, a.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Split expression simplification in multiple parts so that a given op
can appear multiple times. This patch should not change anything.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Now that there are two passes of optimization (optimize.c, liveness)
there is no point of outputing the statistics of the liveness part
only. Update the code to take into account both optimizations.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Some guests need this according to
Alejandro Martinez Ruiz <alex@securiforest.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

... and register subregions instead, so we offload the dispatching
to the the memory subsystem which is designed to handle it.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Everything is in place, flip the big switch now
and enable support for multiple interrupters.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Pick the correct interrupter when queuing an event.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Prepare xhci runtime register access function for multiple interrupters.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Move all state belonging to the (single) interrupter into a separate
struct.  First step in adding support for multiple interrupters.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Now that we have a separate function to raise an IRQ we can move
some comon code into the function.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

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

Split xhci_irq_update into a function which handles intx updates
(including lowering the irq line once the guests acks the interrupt)
and one which is used for raising an irq only.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Drop custom write_config function which isn't needed any more.
Make the msi property a bit property so it accepts 'on' & 'off'.
Enable MSI by default.

TODO: add compat property to disable on old machine types.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Add usb3 descriptors to usb-storage, so it shows up as superspeed
device when connected to xhci.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Add support for creating BOS descriptor and
device cappability descriptors.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Add support for building superspeed endpoint companion descriptors,
create them for superspeed usb devices.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Add superspeed descriptor entry to USBDesc,
advertise superspeed support when present.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

This patch changes the way xhci ports are linked to USBPorts.  The fixed
1:1 relationship between xhci ports and USBPorts is gone.  Now each
USBPort represents a physical plug which has usually two xhci ports
assigned: one usb2 and ond usb3 port.  usb devices show up at one or the
other, depending on whenever they support superspeed or not.

This patch also makes the number of usb2 and usb3 ports runtime
configurable by adding 'p2' and 'p3' properties.  It is allowed to
have different numbers of usb2 and usb3 ports.  Specifying p2=4,p3=2
will give you an xhci adapter which supports all speeds on physical
ports 1+2 and usb2 only on ports 3+4.

Change the register layout to be a bit more sparse and also not depend
on the number of ports.  Useful when for making the number of ports
runtime-configurable.

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

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

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