There is disagreement on whether LSR.THRE should be resampled when
IER.THRI goes from 1 to 1. Bochs only does it if IER.THRI goes from 0
to 1; PCE does it even if IER.THRI is unchanged. But the Windows driver
seems to always go from 1 to 0 and back to 1, so do things in agreement
with Bochs, because the handling of thr_ipending was reported in 2010
(https://lists.gnu.org/archive/html/qemu-devel/2010-03/msg01914.html)
as breaking DR-DOS Plus.
Reported-by: Roy Tam <roytam@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When the transmit FIFO is emptied or enabled, the transmitter
hold register is empty. When it is disabled, it is also emptied and
in addition the previous contents of the transmitter hold register
are discarded. In either case, the THRE bit in LSR must be set and
THRI raised.
When the receive FIFO is emptied or enabled, the data ready and break
bits must be cleared in LSR. Likewise when the receive FIFO is disabled.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- assert TEMT is cleared before sending a character; we'll get one from
TSR if tsr_retry > 0, from the FIFO or THR otherwise
- assert THRE cleared and FIFO not empty (if enabled) before fetching a
character to send. This effectively reverts dffacd46, but the check
makes no sense and commit f702e62 (serial: change retry logic to avoid
concurrency, 2014-07-11) must have made it unnecessary. The commit
message for f702e62 talks about multiple calls to qemu_chr_fe_add_watch
triggering s->tsr_retry >= MAX_XMIT_RETRY, but other failures were
possible. For example, if you have multiple calls, the subsequent ones
will see s->tsr_retry == 0 and will find THRE and/or TEMT on entry.
- for clarity, raise THRI immediately after the code sets THRE
- check THRE to see if another character has to be sent. This makes
the assertions more obvious and also means TEMT has to be set as soon as
the loop ends. It makes the loop send both TSR and THR if flow-control
happens in non-FIFO mode. Previously, THR would be lost.
- clear TEMT together with THRE even in the non-FIFO case
The last two items are bugfixes, but they were just found by inspection
and do not squash known bugs.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is responsible for failure of migration from 2.2 to 2.1, because
thr_ipending is always one in practice.
serial.c is setting thr_ipending unconditionally. However, thr_ipending
is not used at all if THRI=0, and it will be overwritten again the next
time THRE or THRI changes. For that reason, we can set thr_ipending to
zero every time THRI is reset.
There is disagreement on whether LSR.THRE should be resampled when IER.THRI
goes from 1 to 1. This patch does not touch the code, leaving that for
QEMU 2.3+.
This has no semantic change and is enough to fix migration in the common
case where the interrupt is not pending or is reported in IIR. It does not
change the migration format, so 2.2.0 -> 2.1 will remain broken but we
can fix 2.2.1 -> 2.1 without breaking 2.2.1 <-> 2.2.0.
The case that remains broken (the one in which the subsection is strictly
necessary) is when THRE=1, the THRI interrupt has *not* been acknowledged
yet, and a higher-priority interrupt comes. In this case, you need the
subsection to tell the source that the lower-priority THRI interrupt is
pending. The subsection's breakage of migration, in this case, prevents
continuing the VM on the destination with an invalid state.
Cc: qemu-stable@nongnu.org
Reported-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Right now, s->poll_msl may linger at "0" value for an arbitrarily long
time, until serial_update_msl is called for the first time. This is
unnecessary, and will lead to the s->poll_msl field being unnecessarily
migrated.
We can call serial_update_msl immediately at realize time (via
serial_reset) and be done with it. The memory-mapped UART was already
doing that, but not the ISA and PCI variants.
Regarding the delta bits, be consistent with what serial_reset does when
the serial port is not backed by a physical serial port, and always clear
them at reset time.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When a serial port is started, its initial state is all zero. Make
it consistent with reset state instead.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some fields were added to VMState by this patch to preserve correct
loading of the serial port controller state.
Updating FCR value while loading was also modified to disable generating
an interrupt by loadvm.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Whenever serial_xmit fails to transmit a byte it adds a watch that would
call it again when the "line" becomes ready. This results in a retry
chain:
serial_xmit -> add_watch -> serial_xmit
Each chain is able to transmit one character, and for every character
passed to serial by the guest driver a new chain is spawned.
The problem lays with the fact that a new chain is spawned even when
there is one already waiting on the watch. So there can be several retry
chains waiting concurrently on one "line". Every chain tries to transmit
current character, so character order is not messed up. But also every
chain increases retry counter (tsr_retry). If there are enough
concurrent chains this counter will hit MAX_XMIT_RETRY value and
the character will be dropped.
To reproduce this bug you need to feed serial output to some program
consuming it slowly enough. A python script from bug #1335444
description is an example of such program.
This commit changes retry logic in the following way to avoid
concurrency: instead of spawning a new chain for each character being
transmitted spawn only one and make it transmit characters until FIFO is
empty.
The change consists of two parts:
- add a do {} while () loop in serial_xmit (diff is a bit erratic
for this part, diff -w will show actual change),
- do not call serial_xmit from serial_ioport_write if there is one
waiting on the watch already.
This should fix another issue causing bug #1335444.
Signed-off-by: Kirill Batuzov <batuzovk@ispras.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On FreeBSD polling a master pty while the other end is not connected
with G_IO_OUT only results in an endless wait. This is different from
the Linux behaviour, that returns immediately. In order to demonstrate
this, I have the following example code:
http://xenbits.xen.org/people/royger/test_poll.c
When executed on Linux:
$ ./test_poll
In callback
On FreeBSD instead, the callback never gets called:
$ ./test_poll
So, in order to workaround this, poll the source with G_IO_HUP (which
makes the code behave the same way on both Linux and FreeBSD).
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: xen-devel@lists.xenproject.org
[Add hw/char/cadence_uart.c too. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After previous Peter patch, they are redundant. This way we don't
assign them except when needed. Once there, there were lots of case
where the ".fields" indentation was wrong:
.fields = (VMStateField []) {
and
.fields = (VMStateField []) {
Change all the combinations to:
.fields = (VMStateField[]){
The biggest problem (appart from aesthetics) was that checkpatch complained
when we copy&pasted the code from one place to another.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Acked-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
The commit 88c1ee73d3
char/serial: Fix emptyness check
Still causes extra NULL byte(s) to be sent.
So if the fifo is empty, do not send an extra NULL byte.
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Don Slutz <dslutz@verizon.com>
Message-id: 1395160174-16006-1-git-send-email-dslutz@verizon.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This was guarding against a full fifo rather than an empty fifo when
popping. Fix.
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
# By Alex Bligh (32) and others
# Via Stefan Hajnoczi
* stefanha/block: (42 commits)
win32-aio: drop win32_aio_flush_cb()
aio-win32: replace incorrect AioHandler->opaque usage with ->e
aio / timers: remove dummy_io_handler_flush from tests/test-aio.c
aio / timers: Remove legacy interface
aio / timers: Switch entire codebase to the new timer API
aio / timers: Add scripts/switch-timer-api
aio / timers: Add test harness for AioContext timers
aio / timers: convert block_job_sleep_ns and co_sleep_ns to new API
aio / timers: Convert rtc_clock to be a QEMUClockType
aio / timers: Remove main_loop_timerlist
aio / timers: Rearrange timer.h & make legacy functions call non-legacy
aio / timers: Add qemu_clock_get_ms and qemu_clock_get_ms
aio / timers: Remove legacy qemu_clock_deadline & qemu_timerlist_deadline
aio / timers: Remove alarm timers
aio / timers: Add documentation and new format calls
aio / timers: Use all timerlists in icount warp calculations
aio / timers: Introduce new API timer_new and friends
aio / timers: On timer modification, qemu_notify or aio_notify
aio / timers: Convert mainloop to use timeout
aio / timers: Convert aio_poll to use AioContext timers' deadline
...
Message-id: 1377202298-22896-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <anthony@codemonkey.ws>
This is an autogenerated patch using scripts/switch-timer-api.
Switch the entire code base to using the new timer API.
Note this patch may introduce some line length issues.
Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Convert stderr messages calling error_get_pretty()
to error_report().
Timestamp is prepended by -msg timstamp option with it.
Per Markus's comment below, A conversion from fprintf() to
error_report() is always an improvement, regardless of
error_get_pretty().
http://marc.info/?l=qemu-devel&m=137513283408601&w=2
But, it is not reasonable to convert them at one time
because fprintf() is used everwhere in qemu.
So, it should be done step by step with avoiding regression.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Copy&paste error in serial.c causes a crash when attempting
to read from UART (if there is no data to be read)
Signed-off-by: Vladimir Senkov <hangup@gmail.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* 'realize-isa.v2' of git://github.com/afaerber/qemu-cpu:
qdev: Drop FROM_QBUS() macro
isa: QOM'ify ISADevice
isa: QOM'ify ISABus
i8259: Convert PICCommonState to use QOM realizefn
kvm/i8259: QOM'ify some more
i8259: QOM'ify some more
i8254: Convert PITCommonState to QOM realizefn
kvm/i8254: QOM'ify some more
i8254: QOM'ify some more
isa: Use realizefn for ISADevice
cs4231a: QOM'ify some more
gus: QOM'ify some more
These three lines are common to both FIFO and regular mode. Just factor
them out to outside the if rather than replicate the same lines inside
both if and else.
Cc: qemu-trivial@nongnu.org
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Use the generic Fifo8 helper provided by QEMU, rather than re-implement
privately.
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Some cosmetic fixes to char/serial fixing some checkpatch errors.
Cc: qemu-trivial@nongnu.org
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Drop ISADeviceClass::init and the resulting no-op initfn and let
children implement their own realizefn. Adapt error handling.
Split off an instance_init where sensible.
Signed-off-by: Andreas Färber <afaerber@suse.de>
