This patch makes qemu assign a port when creating the device, not when
attaching it. For most usb devices this isn't a noticable difference
because they are in attached state all the time.
The change affects usb-host devices which live in detached state while
the real device is unplugged from the host. They have a fixed port
assigned all the time now instead of getting grabbing one on attach and
releasing it at detach, i.e. they stop floating around at the usb bus.
The change also allows to simplify usb-hub. It doesn't need the
handle_attach() callback any more to configure the downstream ports.
This can be done at device initialitation time now. The changed
initialization order (first grab upstream port, then register downstream
ports) also fixes some icky corner cases. For example it is not possible
any more to plug the hub into one of its own downstream ports.
The usb host adapters must care too. USBPort->dev being non-NULL
doesn't imply any more the device is in attached state. The host
adapters must additionally check the USBPort->dev->attached flag.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch adds code to do minimal siTD handling, which is basically
just following the next pointer. This is good enougth to handle the
inactive siTDs used by FreeBSD. Active siTDs are skipped too as we
don't have split transfer support in qemu, additionally a warning is
printed.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
When configured to pass through a specific host port (using hostbus and
hostport properties), try to claim the port if supported by the kernel.
That will avoid any kernel drivers binding to devices plugged into that
port. It will not stop any userspace apps (such as usb_modeswitch)
access the device via usbfs though.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Add a bunch of trace points to usb-linux.c Drop a bunch of DPRINTK's in
favor of the trace points. Also cleanup error reporting a bit while being
at it.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Given that all events with programmatically-controlled state are disabled by
default, we can delete the "disable" property from all events.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Note that this refers to the backend-specific state (whether the output must be
generated), not the event "disabled" property (which always uses the "nop"
backend).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Polarity of external interrupts needs to be handled in the IOAPIC.
Passing it to the APIC is pointless. So remove all these arguments.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Can be useful when debugging the device scan phase.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
With this patch, sense data is stored in the generic data structures
for SCSI devices and requests. The SCSI layer takes care of storing
sense data in the SCSIDevice for the subsequent REQUEST SENSE command.
At the same time, get_sense is removed and scsi_req_get_sense can use
an entirely generic implementation.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
In order to be able to call bdrv_co_readv/writev for drivers that don't
implement the functions natively, add an emulation that uses the AIO functions
to implement them.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add new block driver callbacks bdrv_co_readv/writev, which work on a
QEMUIOVector like bdrv_aio_*, but don't need a callback. The function may only
be called inside a coroutine, so a block driver implementing this interface can
yield instead of blocking during I/O.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Asynchronous code is becoming very complex. At the same time
synchronous code is growing because it is convenient to write.
Sometimes duplicate code paths are even added, one synchronous and the
other asynchronous. This patch introduces coroutines which allow code
that looks synchronous but is asynchronous under the covers.
A coroutine has its own stack and is therefore able to preserve state
across blocking operations, which traditionally require callback
functions and manual marshalling of parameters.
Creating and starting a coroutine is easy:
coroutine = qemu_coroutine_create(my_coroutine);
qemu_coroutine_enter(coroutine, my_data);
The coroutine then executes until it returns or yields:
void coroutine_fn my_coroutine(void *opaque) {
MyData *my_data = opaque;
/* do some work */
qemu_coroutine_yield();
/* do some more work */
}
Yielding switches control back to the caller of qemu_coroutine_enter().
This is typically used to switch back to the main thread's event loop
after issuing an asynchronous I/O request. The request callback will
then invoke qemu_coroutine_enter() once more to switch back to the
coroutine.
Note that if coroutines are used only from threads which hold the global
mutex they will never execute concurrently. This makes programming with
coroutines easier than with threads. Race conditions cannot occur since
only one coroutine may be active at any time. Other coroutines can only
run across yield.
This coroutines implementation is based on the gtk-vnc implementation
written by Anthony Liguori <anthony@codemonkey.ws> but it has been
significantly rewritten by Kevin Wolf <kwolf@redhat.com> to use
setjmp()/longjmp() instead of the more expensive swapcontext() and by
Paolo Bonzini <pbonzini@redhat.com> for Windows Fibers support.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
"next" is reserved in systemtap thus using this as a
trace parameter name causes trouble when trying to trace
with systemtap.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The map cache is a Xen thing, so its API should make this clear.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Introduce a new emulated PCI device, specific to fully virtualized Xen
guests. The device is necessary for PV on HVM drivers to work.
Signed-off-by: Steven Smith <ssmith@xensource.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch introduces phys memory client for Xen.
Only sync dirty_bitmap and set_memory are actually implemented.
migration_log will stay empty for the moment.
Xen can only log one range for bit change, so only the range in the
first call will be synced.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch fixes a bunch of issues in the itd descriptor handling.
Most important fix is to handle transfers which cross page borders
correctly by looking up the address of the next page. Luckily the
linux uses physically contigous memory so the data used to hits the
correct location even with this bug instead of corrupting guest
memory. Also the transfer length updates for outgoing transfers wasn't
correct.
While being at it DPRINTFs have been replaced by tracepoints.
The isoch_pause logic has been disabled. Not clear to me which propose
this serves and I think it is incorrect too as we just skip processing
itds. Even when no xfer happens we have to clear the active bit.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch adds support for keeping multiple queues going at the same
time. One slow device will not affect other devices any more.
The patch adds code to manage EHCIQueue structs. It also does a number
of changes to the state machine:
* The state machine will never ever stop in EXECUTING any more.
Instead it will continue with the next queue (aka HORIZONTALQH) when
the usb device returns USB_RET_ASYNC.
* The state machine will stop processing when it figures it walks in
circles (easy to figure now that we have a EHCIQueue struct for each
QH we've processed). The bailout logic should not be needed any
more. For now it is still in, but will assert() in case it triggers.
* The state machine will just skip queues with a async USBPacket in
flight.
* The state machine will resume processing as soon as the async
USBPacket is finished.
The patch also takes care to flush the QH struct back to guest memory
when needed, so we don't get stale data when (re-)loading it from guest
memory in FETCHQH state.
It also makes the writeback code to not touch the first three dwords of
the QH struct as the EHCI must not write them. This actually fixes a
bug where QH chaining changes (next ptr) by the linux ehci driver where
overwritten by the emulated EHCI.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Add a separate tracepoint to log how register values change in response
to a mmio write. Especially useful for registers which have read-only
or clear-on-write bits in them.
No change in behavior.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Trace usb port operations (attach, detach, reset),
drop a few obsolete DPRINTF's.
No change in behavior.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Add functions to get and set the current state of the state machine,
add tracepoints there to trace state transitions. Add support for
traceing the queue heads and transfer descriptors as we look at them.
Drop a few DPRINTFs and all DPRINTF_ST lines, they are obsolete now.
No change in behavior.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch starts adding trace support to ehci. It traces
updates of the status register (USBSTS), mmio access and
controller reset.
It also adds functions to set and clear status register bits
and puts them in use everywhere.
Some DPRINTF's are dropped in favor of the new tracepoints.
No change in behavior.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The simple backend only supports a maximum of 6 arguments. Split the
scsi_req_parsed event in two parts to cope with the limit.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This abstracts calling the command_complete callback, reducing churn
in the following patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
One strategy to limit the startup delay of consistency check when
opening image files is to ensure that the file is marked dirty for as
little time as possible.
QED currently marks the image dirty when the first allocating write
request is issued and clears the dirty bit again when the image is
cleanly closed. In practice that means the image is marked dirty for
most of a guest's lifetime and prone to being in a dirty state upon
crash or power failure.
It is safe to clear the dirty bit after all allocating write requests
have completed and a flush has been performed. This patch adds a timer
after the last allocating write request completes. When the timer fires
it will flush and then clear the dirty bit. The timer is set to 5
seconds and is cancelled upon arrival of a new allocating write request.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function allows to unlock a ram_ptr give by qemu_get_ram_ptr. After
a call to qemu_put_ram_ptr, the pointer may be unmap from QEMU when
used with Xen.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
On IA32 host or IA32 PAE host, at present, generally, we can't create
an HVM guest with more than 2G memory, because generally it's almost
impossible for Qemu to find a large enough and consecutive virtual
address space to map an HVM guest's whole physical address space.
The attached patch fixes this issue using dynamic mapping based on
little blocks of memory.
Each call to qemu_get_ram_ptr makes a call to qemu_map_cache with the
lock option, so mapcache will not unmap these ram_ptr.
Blocks that do not belong to the RAM, but usually to a device ROM or to
a framebuffer, are handled in a separate function. So the whole RAMBlock
can be map.
Signed-off-by: Jun Nakajima <jun.nakajima@intel.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This patch adds support for Milkymist's minimal Ethernet MAC v2. It
superseds minimac1.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Trace events cannot use %s in their format strings because trace
backends vary in how they can deference pointers (if at all). Recording
const char * values is not meaningful if their contents are not recorded
too.
Change grlib trace events that rely on strings so that they communicate
similar information without using strings.
A follow-up patch explains this limitation and updates docs/tracing.txt.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
It can be handy to know when the guest locks/unlocks the CD-ROM tray.
This trace event makes that possible.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch adds support for Milkymist's VGA framebuffer.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's simple UART.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's texture mapping unit. For fast
computation this model needs hardware accelerated 3D graphics support
(OpenGL). There is no graphical output, all computations belong to internal
framebuffers only.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's System Controller core. The model
has the following features:
- support for shutting down and restarting the board
- provide two timers and GPIO
- provide registers for system identification and reading the boards
capabilities
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's SoftUSB core. This model differ
from the real hardware in its functionality. The real hardware consits of a
tiny freely programmable microcontroller which controls the USB ports. For
simplicity reasons, this model emulates only keyboard and mouse input
devices, eg. input events translates directly to the corresponding expected
messages.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's Programmable FPU.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's minimal Ethernet MAC.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for Milkymist's memory card core.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for the Milkymist's High Performance Dynamic Memory
Controller. This is just a dumb model without any functionality. While the
real hardware acts for example as a bridge between software and hardware
for sending SDRAM commans, this model will only eat up these commands and
always returns the expected hardware states, eg. PLL locked etc.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for the Milkymist AC97 compatible sound output and
input core.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds paio_complete() and paio_cancel() trace events to
complement the paio_submit() event.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Add a trace event for bdrv_aio_flush() to complement the existing
bdrv_aio_readv() and bdrv_aio_writev() events.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This patch add support for a system control block. It is supposed to
act as helper for the emulated program. E.g. shutting down the VM or
printing test results. This model is intended for testing purposes only and
doesn't fit to any real hardware. Therefore, it is not added to any board
by default. Instead a user has to add it explicitly with the '-device'
commandline parameter.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch add support for the LatticeMico32 UART.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds support for the LatticeMico32 system timer.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds the JTAG UART model. It is accessed through special control
registers and opcodes. Therefore the translation uses callbacks to this
model.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
This patch adds the interrupt controller of the lm32. Because the PIC is
accessed through special control registers and opcodes, there are callbacks
from the lm32 translation code to this model.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Leon3 is an open-source VHDL System-On-Chip, well known in space industry (more
information on http://www.gaisler.com).
Leon3 is made of multiple components available in the GrLib VHDL library.
Three devices are implemented: uart, timers and IRQ manager.
You can find code for these peripherals in the grlib_* files.
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This device exposes one parameter:
- chardev (ptr) : Pointer to a qemu character device
Emulation of GrLib devices is base on the GRLIB IP Core User's Manual:
http://www.gaisler.com/products/grlib/grip.pdf
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This device exposes two parameters:
- set_pil_in (ptr) : A function to set the pil_in of the SPARC CPU
- set_pil_in_opaque (ptr) : Opaque argument of the set_pil_in function
Emulation of GrLib devices is base on the GRLIB IP Core User's Manual:
http://www.gaisler.com/products/grlib/grip.pdf
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This device exposes three parameters:
- frequency (uint32) : The system frequency
- irq-line (uint32) : IRQ line number for the first timer
(others use irq-line + 1, irq-line + 2...)
- nr-timers (uint32) : Number of timers
Emulation of GrLib devices is base on the GRLIB IP Core User's Manual:
http://www.gaisler.com/products/grlib/grip.pdf
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Adding a chardev backend for spice, where spice determines what
to do with it based on the name attribute given during chardev creation.
For usage by spice vdagent in conjunction with a properly named
virtio-serial device, and future smartcard channel usage.
Example usage:
qemu -device virtio-serial -chardev spicevmc,name=vdagent,id=vdagent \
-device virtserialport,chardev=vdagent,name=com.redhat.spice.0
v4->v5:
* add tracing events
* fix missing comma
* fix help string to show debug is optional
v3->v4:
* updated commit message
v1->v3 changes: (v2 had a wrong commit message)
* removed spice-qemu-char.h, folded into ui/qemu-spice.h
* removed dead IOCTL code
* removed comment
* removed ifdef CONFIG_SPICE from qemu-config.c and qemu-options.hx help.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Add support for device_qualifier and other_speed_config descriptors.
These are used to query the "other speed" configuration of usb 2.0
devices, i.e. in high-speed mode they return the full-speed
configuration and visa versa.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch moves setting and clearing the remote_wakeup feature
bit (via USB_REQ_{SET,CLEAR}_FEATURE) to common code. Also
USB_REQ_GET_STATUS handling is moved to common code.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch adds fields to the USBDevice struct for the current
speed (hard-wired to full speed for now) and current device
configuration. Also a init function is added which inializes
these fields. This allows USB_REQ_{GET,SET}_CONFIGURATION
handling to be moved to common code.
For most drivers the conversion is trivial ad they support a single
configuration only anyway. One exception is bluetooth where some
device-specific setup code runs after get/set configuration. The
other is usb-net which actually has two configurations so the
the code to check for the active configuration has been adapted.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch adds hw/usb-desc.[ch] files. They carry data structures
for various usb descriptors and helper functions to generate usb
packets from the structures.
The intention is to have a internal representation of the device
desription which is more usable than the current char array blobs,
so we can have common code handle common usb device emulation using
the device description.
The usage of this infrastructure is optional for usb drivers as there
are cases such as pass-through where it probably isn't very useful.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch implements the read/write state machine. Operations are
fully asynchronous and multiple operations may be active at any time.
Allocating writes lock tables to ensure metadata updates do not
interfere with each other. If two allocating writes need to update the
same L2 table they will run sequentially. If two allocating writes need
to update different L2 tables they will run in parallel.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch adds code to look up data cluster offsets in the image via
the L1/L2 tables. The L2 tables are writethrough cached in memory for
performance (each read/write requires a lookup so it is essential to
cache the tables).
With cluster lookup code in place it is possible to implement
bdrv_is_allocated() to query the number of contiguous
allocated/unallocated clusters.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
VM state change notifications are invoked from vm_start()/vm_stop().
Trace these state changes so we can reason about the state of the VM
from trace output.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Replace debug printf statements with tracepoints.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Observing block layer aio readv/writev operations is useful for
debugging image formats or understanding guest disk I/O patterns.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
It is not portable to use "%ld" for int64_t because int64_t may have
type long on 64-bit platforms and long long on 32-bit platforms. Use
the standard library PRId64 macros to keep format strings portable.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This patch adds trace events for virtqueue operations including
adding/removing buffers, notifying the guest, and receiving a notify
from the guest.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
It is often useful to instrument memory management functions in order to
find leaks or performance problems. This patch adds trace events for
the memory allocation primitives.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Sometimes it is useful to disable a trace event. Removing the event
from trace-events is not enough since source code will call the
trace_*() function for the event.
This patch makes it easy to build without specific trace events by
marking them disabled in trace-events:
disable multiwrite_cb(void *mcb, int ret) "mcb %p ret %d"
This builds without the multiwrite_cb trace event.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
trace: Allow bulk enabling/disabling of trace events at compile time
For 'simple' trace backend, allow bulk enabling/disabling of trace
events at compile time. Trace events that are preceded by 'disable'
keyword are compiled in, but turned off by default. These can
individually be turned on using the monitor. All other trace events are
enabled by default.
TODO :
This could be enhanced when the trace-event namespace is partitioned into a
group and an ID within that group. In such a case, marking a group as enabled
would automatically enable all trace-events listed under it.
Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This patch introduces the trace-events file where trace events can be
declared like so:
qemu_malloc(size_t size) "size %zu"
qemu_free(void *ptr) "ptr %p"
These trace event declarations are processed by a new tool called
tracetool to generate code for the trace events. Trace event
declarations are independent of the backend tracing system (LTTng User
Space Tracing, ftrace markers, DTrace).
The default "nop" backend generates empty trace event functions.
Therefore trace events are disabled by default.
The trace-events file serves two purposes:
1. Adding trace events is easy. It is not necessary to understand the
details of a backend tracing system. The trace-events file is a
single location where trace events can be declared without code
duplication.
2. QEMU is not tightly coupled to one particular backend tracing system.
In order to support tracing across QEMU host platforms and to
anticipate new backend tracing systems that are currently maturing,
it is important to be flexible and not tied to one system.
This commit includes fixes from Prerna Saxena
<prerna@linux.vnet.ibm.com> and Blue Swirl <blauwirbel@gmail.com>.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
