This adds a couple of tcg specific trace-events which are useful for
tracing execution though tcg generated blocks. It's been tested with
lttng user space tracing but is generic enough for all systems. The tcg
events are:
* translate_block - when a subject block is translated
* exec_tb - when a translated block is entered
* exec_tb_exit - when we exit the translated code
* exec_tb_nocache - special case translations
Of course we can only trace the entrance to the first block of a chain
as each block will jump directly to the next when it can. See the -d
nochain patch to allow more complete tracing at the expense of
performance.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Show in 'info jit' the current delay between the host clock
and the guest clock. In addition, print the maximum advance
and delay of the guest compared to the host.
Signed-off-by: Sebastian Tanase <sebastian.tanase@openwide.fr>
Tested-by: Camille Bégué <camille.begue@openwide.fr>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If the align option is enabled, we print to the user whenever
the guest clock is behind the host clock in order for he/she
to have a hint about the actual performance. The maximum
print interval is 2s and we limit the number of messages to 100.
If desired, this can be changed in cpu-exec.c
Signed-off-by: Sebastian Tanase <sebastian.tanase@openwide.fr>
Tested-by: Camille Bégué <camille.begue@openwide.fr>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The goal is to sleep qemu whenever the guest clock
is in advance compared to the host clock (we use
the monotonic clocks). The amount of time to sleep
is calculated in the execution loop in cpu_exec.
At first, we tried to approximate at each for loop the real time elapsed
while searching for a TB (generating or retrieving from cache) and
executing it. We would then approximate the virtual time corresponding
to the number of virtual instructions executed. The difference between
these 2 values would allow us to know if the guest is in advance or delayed.
However, the function used for measuring the real time
(qemu_clock_get_ns(QEMU_CLOCK_REALTIME)) proved to be very expensive.
We had an added overhead of 13% of the total run time.
Therefore, we modified the algorithm and only take into account the
difference between the 2 clocks at the begining of the cpu_exec function.
During the for loop we try to reduce the advance of the guest only by
computing the virtual time elapsed and sleeping if necessary. The overhead
is thus reduced to 3%. Even though this method still has a noticeable
overhead, it no longer is a bottleneck in trying to achieve a better
guest frequency for which the guest clock is faster than the host one.
As for the the alignement of the 2 clocks, with the first algorithm
the guest clock was oscillating between -1 and 1ms compared to the host clock.
Using the second algorithm we notice that the guest is 5ms behind the host, which
is still acceptable for our use case.
The tests where conducted using fio and stress. The host machine in an i5 CPU at
3.10GHz running Debian Jessie (kernel 3.12). The guest machine is an arm versatile-pb
built with buildroot.
Currently, on our test machine, the lowest icount we can achieve that is suitable for
aligning the 2 clocks is 6. However, we observe that the IO tests (using fio) are
slower than the cpu tests (using stress).
Signed-off-by: Sebastian Tanase <sebastian.tanase@openwide.fr>
Tested-by: Camille Bégué <camille.begue@openwide.fr>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On the x86, some devices need access to the CPU reset pin (INIT#).
Provide a generic service to do this, using one of the internal
cpu_interrupt targets. Generalize the PPC-specific code for
CPU_INTERRUPT_RESET to other targets.
Since PPC does not support migration across QEMU versions (its
machine types are not versioned yet), I picked the value that
is used on x86, CPU_INTERRUPT_TGT_INT_1. Consequently, TGT_INT_2
and TGT_INT_3 are shifted down by one while keeping their value.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If the guest attempts to execute from unreadable memory, this will
cause us to longjmp back to the main loop from inside the
target frontend decoder. For linux-user mode, this means we will
still hold the tb_ctx.tb_lock, and will deadlock when we try to
start executing code again. Unlock the lock in the return-from-longjmp
code path to avoid this.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andrei Warkentin <andrey.warkentin@gmail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Default to false.
Tidy variable naming and inline cast uses while at it.
Tested-by: Jia Liu <proljc@gmail.com> (or32)
Signed-off-by: Andreas Färber <afaerber@suse.de>
To avoid complication in code that otherwise would not need to
care about whether EL1 is AArch32 or AArch64, we should store
the interrupt mask bits (CPSR.AIF in AArch32 and PSTATE.DAIF
in AArch64) in one place consistently regardless of EL1's mode.
Since AArch64 has an extra enable bit (D for debug exceptions)
which isn't visible in AArch32, this means we need to keep
the enables in env->pstate. (This is also consistent with the
general approach we're taking that we handle 32 bit CPUs as
being like AArch64/ARMv8 CPUs but which only run in 32 bit mode.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
The previous placement could result in duplicate logging while
still processing interrupts.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Replace growing numbers of inline x86_env_get_cpu() with x86_cpu variable.
Reviewed-by: Chen Fan <chen.fan@cn.fujitsu.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
This motion is preparing for refactoring vCPU APIC subsequently.
Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Local variable CPUClass *cc needs to be reloaded after return from longjmp,
too. (This fixes a mips-softmmu crash observed on FreeBSD when QEMU is
built with clang.)
Reported-by: Dimitry Andric <dim@FreeBSD.org>
Signed-off-by: Juergen Lock <nox@jelal.kn-bremen.de>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Prepares for changing cpu_single_step() argument to CPUState.
Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Signed-off-by: Andreas Färber <afaerber@suse.de>
Where no extra implementation is needed, fall back to CPUClass::set_pc().
Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Signed-off-by: Andreas Färber <afaerber@suse.de>
Since commit 878096eeb2 (cpu: Turn
cpu_dump_{state,statistics}() into CPUState hooks) CPUArchState is no
longer needed.
Add documentation and make the functions available through qemu/log.h
outside NEED_CPU_H to allow use in qom/cpu.c. Moving them to qom/cpu.h
was not yet possible due to convoluted include paths, so that some
devices grow an implicit and unneeded dependency on qom/cpu.h for now.
Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Reviewed-by: Richard Henderson <rth@twiddle.net>
[AF: Simplified mb_cpu_do_interrupt() and do_interrupt_all() changes]
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: liguang <lig.fnst@cn.fujitsu.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
* 'mingw' of git://qemu.weilnetz.de/qemu:
qemu-timer: move timeBeginPeriod/timeEndPeriod to os-win32
Release SMP restriction on Windows
Ensure good ordering of memory instruction in cpu_exec
Check effective suspension of TCG thread
The IO thread, when it senses cpu_single_env == 0, expects exit_request
to be checked later on. A compiler scheduling constraint is not strong
enough to ensure this on modern architecture. A memory fence is needed
as well.
Signed-off-by: Olivier Hainque <hainque@adacore.com>
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
The CONFIG_DEBUG_EXEC define compiles out a single qemu_log_mask()
call, which is a pretty trivial cost even for something in the main
cpu_exec() loop. Having this be conditionally defined means that
'-d exec' on a non-debug build will silently do nothing. Drop the
define and the configure machinery that sets it, in favour of just
always allowing this log option to be enabled at runtime. As a
concession to the mainloopiness, we use qemu_loglevel_mask()+qemu_log()
rather than qemu_log_mask() to avoid the function call overhead.
Note that DEBUG_DISAS is always defined, so removing the
'|| defined(CONFIG_DEBUG_EXEC)' from those conditionals makes
no behavioural change for that logging.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
We can compute the value in cpu_dump_state anyway, and gratuitous
modifications to eflags creates heisenbugs.
Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This removes a global per-target function and thus takes us one step
closer to compiling multiple targets into one executable.
It will also allow to override the interrupt handling for certain CPU
families.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Both fields are used in VMState, thus need to be moved together.
Explicitly zero them on reset since they were located before
breakpoints.
Pass PowerPCCPU to kvmppc_handle_halt().
Signed-off-by: Andreas Färber <afaerber@suse.de>
Fix some of the nasty TCG race conditions and crashes by implementing
cpu_exit() as setting a flag which is checked at the start of each TB.
This avoids crashes if a thread or signal handler calls cpu_exit()
while the execution thread is itself modifying the TB graph (which
may happen in system emulation mode as well as in linux-user mode
with a multithreaded guest binary).
This fixes the crashes seen in LP:668799; however there are another
class of crashes described in LP:1098729 which stem from the fact
that in linux-user with a multithreaded guest all threads will
use and modify the same global TCG date structures (including the
generated code buffer) without any kind of locking. This means that
multithreaded guest binaries are still in the "unsupported"
category.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
If tcg_qemu_tb_exec() returns a value whose low bits don't indicate a
link to an indexed next TB, this means that the TB execution never
started (eg because the instruction counter hit zero). In this case the
guest PC has to be reset to the address of the start of the TB.
Refactor the cpu-exec code to make all tcg_qemu_tb_exec() calls pass
through a wrapper function which does this restoration if necessary.
Note that the apparent change in cpu_exec_nocache() from calling
cpu_pc_from_tb() with the old TB to calling it with the TB returned by
do_tcg_qemu_tb_exec() is safe, because in the nocache case we can
guarantee that the TB we try to execute is not linked to any others,
so the only possible returned TB is the one we started at. That is,
we should arguably previously have included in cpu_exec_nocache() an
assert(next_tb & ~TB_EXIT_MASK) == tb), since the API requires restore
from next_tb but we were using tb.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Document tcg_qemu_tb_exec(). In particular, its return value is a
combination of a pointer to the next translation block and some
extra information in the low two bits. Provide some #defines for
the values passed in these bits to improve code clarity.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
The setjmp() function doesn't specify whether signal masks are saved and
restored; on Linux they are not, but on BSD (including MacOSX) they are.
We want to have consistent behaviour across platforms, so we should
always use "don't save/restore signal mask" (this is also generally
going to be faster). This also works around a bug in MacOSX where the
signal-restoration on longjmp() affects the signal mask for a completely
different thread, not just the mask for the thread which did the longjmp.
The most visible effect of this was that ctrl-C was ignored on MacOSX
because the CPU thread did a longjmp which resulted in its signal mask
being applied to every thread, so that all threads had SIGINT and SIGTERM
blocked.
The POSIX-sanctioned portable way to do a jump without affecting signal
masks is to siglongjmp() to a sigjmp_buf which was created by calling
sigsetjmp() with a zero savemask parameter, so change all uses of
setjmp()/longjmp() accordingly. [Technically POSIX allows sigsetjmp(buf, 0)
to save the signal mask; however the following siglongjmp() must not
restore the signal mask, so the pair can be effectively considered as
"sigjmp/longjmp which don't touch the mask".]
For Windows we provide a trivial sigsetjmp/siglongjmp in terms of
setjmp/longjmp -- this is OK because no user will ever pass a non-zero
savemask.
The setjmp() uses in tests/tcg/test-i386.c and tests/tcg/linux-test.c
are left untouched because these are self-contained singlethreaded
test programs intended to be run under QEMU's Linux emulation, so they
have neither the portability nor the multithreading issues to deal with.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Tested-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Explictly NULL it on CPU reset since it was located before breakpoints.
Change vapic_report_tpr_access() argument to CPUState. This also
resolves the use of void* for cpu.h independence.
Change vAPIC patch_instruction() argument to X86CPU.
Signed-off-by: Andreas Färber <afaerber@suse.de>
It's worth to clean-up translation blocks variables and move them
into one context as was suggested by Swirl.
Also if we use this context directly inside tcg_ctx, then it
speeds up code generation a bit.
Signed-off-by: Evgeny Voevodin <evgenyvoevodin@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
For target-mips also change the return type to bool.
Make include paths for cpu-qom.h consistent for alpha and unicore32.
Signed-off-by: Andreas Färber <afaerber@suse.de>
[AF: Updated new target-openrisc function accordingly]
Acked-by: Richard Henderson <rth@twiddle.net> (for alpha)
Move the DUMP_FPU and DUMP_CCOP flags for cpu_dump_state() from being
x86-specific flags to being generic ones. This allows us to drop some
TARGET_I386 ifdefs in various places, and means that we can (potentially)
be more consistent across architectures about which monitor commands or
debug abort printouts include FPU register contents and info about
QEMU's condition-code optimisations.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
