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>
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>
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>
Many of these should be cleaned up with proper qdev-/QOM-ification.
Right now there are many catch-all headers in include/hw/ARCH depending
on cpu.h, and this makes it necessary to compile these files per-target.
However, fixing this does not belong in these patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This fixes the build of hw/serial.c with DEBUG_SERIAL enabled.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Done with this script:
cd hw
for i in `find . -name '*.h' | sed 's/^..//'`; do
echo '\,^#.*include.*["<]'$i'[">], s,'$i',hw/&,'
done | sed -i -f - `find . -type f`
This is so that paths remain valid as files are moved.
Instead, files in hw/dataplane are referenced with the relative path.
We know they are not going to move to include/, and they are the only
include files that are in subdirectories _and_ move.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This reverts commit 67c5322d7000fd105a926eec44bc1765b7d70bdd:
I'm not sure if the retry logic has ever worked when not using FIFO mode. I
found this while writing a test case although code inspection confirms it is
definitely broken.
The TSR retry logic will never actually happen because it is guarded by an
'if (s->tsr_rety > 0)' but this is the only place that can ever make the
variable greater than zero. That effectively makes the retry logic an 'if (0)
I believe this is a typo and the intention was >= 0. Once this is fixed thoug
I see double transmits with my test case. This is because in the non FIFO
case, serial_xmit may get invoked while LSR.THRE is still high because the
character was processed but the retransmit timer was still active.
We can handle this by simply checking for LSR.THRE and returning early. It's
possible that the FIFO paths also need some attention.
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Even if the previous logic was never worked, new logic breaks stuff -
namely,
qemu -enable-kvm -nographic -kernel /boot/vmlinuz-$(uname -r) -append console=ttyS0 -serial pty
the above command will cause the virtual machine to stuck at startup
using 100% CPU till one connects to the pty and sends any char to it.
Note this is rather typical invocation for various headless virtual
machines by libvirt.
So revert this change for now, till a better solution will be found.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Replace all register_ioport_*() with a MemoryRegion.
This permits to use the new Memory stuff like listeners.
For more flexibility, the IO address space is passed as an argument.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Avi Kivity <avi@redhat.com>
[AF: Rebased onto serial split]
Signed-off-by: Andreas Färber <afaerber@suse.de>
target_phys_addr_t is unwieldly, violates the C standard (_t suffixes are
reserved) and its purpose doesn't match the name (most target_phys_addr_t
addresses are not target specific). Replace it with a finger-friendly,
standards conformant hwaddr.
Outstanding patchsets can be fixed up with the command
git rebase -i --exec 'find -name "*.[ch]"
| xargs s/target_phys_addr_t/hwaddr/g' origin
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Split serial.c into serial.c, serial.h and serial-isa.c. While being at
creating a serial.h header file move the serial prototypes from pc.h to
the new serial.h. The latter leads to s/pc.h/serial.h/ in tons of
boards which just want the serial bits from pc.h
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
We never actually clear the TEMT (transmit sending register empty) flag when
populating the TSR. We set the flag, but since it's never cleared, setting it
is sort of pointless..
I found this with a unit test case.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
I'm not sure if the retry logic has ever worked when not using FIFO mode. I
found this while writing a test case although code inspection confirms it is
definitely broken.
The TSR retry logic will never actually happen because it is guarded by an
'if (s->tsr_rety > 0)' but this is the only place that can ever make the
variable greater than zero. That effectively makes the retry logic an 'if (0)'.
I believe this is a typo and the intention was >= 0. Once this is fixed though,
I see double transmits with my test case. This is because in the non FIFO
case, serial_xmit may get invoked while LSR.THRE is still high because the
character was processed but the retransmit timer was still active.
We can handle this by simply checking for LSR.THRE and returning early. It's
possible that the FIFO paths also need some attention.
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add a 'wakeup' property to the serial port. It is off by default. When
enabled any incoming character on the serial line will wake up the
guest. Useful for guests which have a serial console configured.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Replace device_init() with generalized type_init().
While at it, unify naming convention: type_init([$prefix_]register_types)
Also, type_init() is a function, so add preceding blank line where
necessary and don't put a semicolon after the closing brace.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Cc: Anthony Liguori <anthony@codemonkey.ws>
Cc: malc <av1474@comtv.ru>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This was done in a mostly automated fashion. I did it in three steps and then
rebased it into a single step which avoids repeatedly touching every file in
the tree.
The first step was a sed-based addition of the parent type to the subclass
registration functions.
The second step was another sed-based removal of subclass registration functions
while also adding virtual functions from the base class into a class_init
function as appropriate.
Finally, a python script was used to convert the DeviceInfo structures and
qdev_register_subclass functions to TypeInfo structures, class_init functions,
and type_register_static calls.
We are almost fully converted to QOM after this commit.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This converts two devices at once because PIC subclasses ISA and converting
subclasses independently is extremely hard.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Remove the get_system_memory() call from serial_mm_init, pushing
it back into the callers. In many cases we already have the
system memory region available.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
The use of DEVICE_NATIVE_ENDIAN cleans up lots of ifdefs in
many of the callers.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
This was done with:
sed -i 's/qemu_get_clock\>/qemu_get_clock_ns/' \
$(git grep -l 'qemu_get_clock\>' )
sed -i 's/qemu_new_timer\>/qemu_new_timer_ns/' \
$(git grep -l 'qemu_new_timer\>' )
after checking that get_clock and new_timer never occur twice
on the same line. There were no missed occurrences; however, even
if there had been, they would have been caught by the compiler.
There was exactly one false positive in qemu_run_timers:
- current_time = qemu_get_clock (clock);
+ current_time = qemu_get_clock_ns (clock);
which is of course not in this patch.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini
Pavel Dovgalyuk
Kirill Batuzov
Roger Pau Monne
Juan Quintela
Don Slutz
Peter Crosthwaite
Alex Bligh
Seiji Aguchi
Vladimir Senkov
Andreas Färber
Kevin Wolf
Anthony Liguori
Michael Tokarev
Julien Grall
Alexander Graf
Avi Kivity
Gerd Hoffmann
Richard Henderson
Blue Swirl