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>
This patch provides a way to optionally suppress spurious interrupts,
as a workaround for systems described below:
Some old operating systems do not handle spurious interrupts well,
and qemu tends to generate them significantly more often than
real hardware.
Examples:
- Microport UNIX System V/386 v 2.1 (ca 1987)
(The main problem I'm fixing: Without this patch, it panics
sporadically when accessing the hard disk.)
- AT&T UNIX System V/386 Release 4.0 Version 2.1a (ca 1991)
See screenshot in "QEMU Official OS Support List":
http://www.claunia.com/qemu/objectManager.php?sClass=application&iId=9
(I don't have this system to test.)
- A report about OS/2 boot lockup from 2004 by Hampa Hug:
http://lists.nongnu.org/archive/html/qemu-devel/2004-09/msg00367.html
(My patch was partially inspired by his.)
Also: http://lists.nongnu.org/archive/html/qemu-devel/2005-06/msg00243.html
(I don't have this system to test.)
Signed-off-by: Matthew Ogilvie <mmogilvi_qemu@miniinfo.net>
Signed-off-by: malc <av1474@comtv.ru>
This patch initializes the cpuid to exactly correct value because
linux kernel will check it.
In addition, the exception types are specified in proper situations.
Then it could make exceptions generated correctly and timely.
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
* 'x86cpu_qom_tcg_v2' of git://github.com/imammedo/qemu:
target-i386: move tcg initialization into x86_cpu_initfn()
cleanup cpu_set_debug_excp_handler
target-xtensa: drop usage of prev_debug_excp_handler
target-i386: drop usage of prev_debug_excp_handler
KVM performs TPR raising asynchronously to QEMU, specifically outside
QEMU's global lock. When an interrupt is injected into the APIC and TPR
is checked to decide if this can be delivered, a stale TPR value may be
used, causing spurious interrupts in the end.
Fix this by deferring apic_update_irq to the context of the target VCPU.
We introduce a new interrupt flag for this, CPU_INTERRUPT_POLL. When it
is set, the VCPU calls apic_poll_irq before checking for further pending
interrupts. To avoid special-casing KVM, we also implement this logic
for TCG mode.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Add an explicit CPUX86State parameter instead of relying on AREG0.
Merge raise_exception_env() to raise_exception(), likewise with
raise_exception_err_env() and raise_exception_err().
Introduce cpu_svm_check_intercept_param() and cpu_vmexit()
as wrappers.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
There are no users left for previous exception handler returned from
cpu_set_debug_excp_handler. It should simplify code a little.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
- The M-flag is encoded in different bits on cris v10 and cris v32.
Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
CPUState will be needed for all targets in the future, so place it into
the main variable declaration block.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Alexander Graf <agraf@suse.de>
Allows to use cpu_reset() in place of cpu_state_reset().
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
The idea behind qtest is pretty simple. Instead of executing a CPU via TCG or
KVM, rely on an external process to send events to the device model that the CPU
would normally generate.
qtest presents itself as an accelerator. In addition, a new option is added to
establish a qtest server (-qtest) that takes a character device. This is what
allows the external process to send CPU events to the device model.
qtest uses a simple line based protocol to send the events. Documentation of
that protocol is in qtest.c.
I considered reusing the monitor for this job. Adding interrupts would be a bit
difficult. In addition, logging would also be difficult.
qtest has extensive logging support. All protocol commands are logged with
time stamps using a new command line option (-qtest-log). Logging is important
since ultimately, this is a feature for debugging.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
next_tb is the numeric value of a tcg target (= QEMU host) address.
Using tcg_target_ulong instead of unsigned long shows this and makes
the code portable for hosts with an unusual size of long (w64).
The type cast '(long)(next_tb & ~3)' was not needed (casting
unsigned long to long does not change the bits, and nor does
casting long to pointer for most (= all non w64) hosts.
It is removed here.
Macro or function tcg_qemu_tb_exec is used to set next_tb.
The function also returns next_tb. Therefore tcg_qemu_tb_exec
must return a tcg_target_ulong.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Scripted conversion:
for file in *.[hc] hw/*.[hc] hw/kvm/*.[hc] linux-user/*.[hc] linux-user/m68k/*.[hc] bsd-user/*.[hc] darwin-user/*.[hc] tcg/*/*.[hc] target-*/cpu.h; do
sed -i "s/CPUState/CPUArchState/g" $file
done
All occurrences of CPUArchState are expected to be replaced by QOM CPUState,
once all targets are QOM'ified and common fields have been extracted.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Frees the identifier cpu_reset for QOM CPUs (manual rename).
Don't hide the parameter type behind explicit casts, use static
functions with strongly typed argument to indirect.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
On ppc405ep there is a register that allows for software to reset the
core, but not the whole system. Implement this reset using a reset
interrupt.
This gets rid of a bunch of #if 0'ed code.
Reported-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Each target uses the #define macro (in target-xxx/cpu.h) to rename
cpu_exec (cpu-exec.c) to cpu_xxx_exec, then defines its own cpu_loop
which calls cpu_xxx_exec. So basically, cpu-exec.c is not only the i386
emulator main execution loop. This patch corrects the comment of this
file and does indentation cleanup.
Signed-off-by: Chen Wei-Ren (陳韋任) <chenwj@iis.sinica.edu.tw>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
In the current emulation of the load-and-reserve (lwarx) and
store-conditional (stwcx.) instructions, the internal reservation
mechanism is taken into account, however each CPU has its own
reservation information and this information is not synchronized between
CPUs to perform proper synchronization.
The following test case with 2 CPUs shows that the semantics of the
"lwarx" and "stwcx." instructions are not preserved by the emulation.
The test case does the following :
- CPU0: reserve a memory location
- CPU1: reserve the same memory location
- CPU0: perform stwcx. on the location
The last store-conditional operation succeeds while it is supposed to
fail since the reservation was supposed to be lost at the second reserve
operation.
This (one line) patch fixes this problem in a very simple manner by
removing the reservation of a CPU every time it is scheduled (in
cpu_exec()). While this is a harsh workaround, it does not affect the
guest code much because reservations are usually held for a very short
time, that is an lwarx is almost always followed by an stwcx. a few
instructions below. Therefore, in most cases, the reservation will be
taken and consumed before a CPU switch occurs. However in the rare case
where a CPU switch does occur between the lwarx and its corresponding
stwcx. this patch solves a potential erroneous behavior of the
synchronization instructions.
Signed-off-by: Elie Richa <richa@adacore.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
- mark privileged opcodes with ring check;
- make debug exception on exception handler entry.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Avoid this warning from clang analyzer:
/src/qemu/cpu-exec.c:97:5: warning: Value stored to 'phys_page2' is never read
phys_page2 = -1;
Adjust the scope of the variable while at it.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Recent compilers look deep into cpu_exec, find longjmp as a noreturn
function and decide to smash some stack variables as they won't be used
again. This may lead to env becoming invalid after return from setjmp,
causing crashes. Fix it by reloading env from cpu_single_env in that
case.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Make functions take a parameter for CPUState instead of relying
on global env. Pass CPUState pointer to TCG prologue, which moves
it to AREG0.
Thanks to Peter Maydell and Laurent Desnogues for the ARM prologue
change.
Revert the hacks to avoid AREG0 use on Sparc hosts.
Move cpu_has_work() and cpu_pc_from_tb() from exec.h to cpu.h.
Compile the file without HELPER_CFLAGS.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Before the next patch, fix coding style of the areas affected.
Change the type of the return value from cpu_has_work() and
qemu_cpu_has_work() to bool.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Now that all targets use common function signature for do_interrupt(), there is no
need for the #ifdeffery anymore.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Pass CPUState to do_interrupt(). This is needed by later patches.
It would be cleaner to move the function to helper.c, but there are
a few dependencies between do_interrupt() and other functions.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Several x86 specific functions are called from cpu-exec.c with the
assumption that global env register is valid. This will be changed
later, so make the functions use caller supplied CPUState parameter.
It would be cleaner to move the functions to helper.c, but there are
quite a lot of dependencies between do_interrupt() and other functions.
Add helpers for svm_check_intercept() and cpu_cc_compute_all() instead
of calling the helper (which uses global env, AREG0) directly.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
There is little in common with user and softmmu versions of cpu_resume_signal(),
split them.
Fix coding style for the user emulator part.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
tb_invalidate_page_range() was intended to be used to invalidate an
area of a TB which the guest explicitly flushes from i-cache. However,
QEMU detects writes to code areas where TBs have been generated, so
his has never been useful.
Delete the function, adjust callers.
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This bit is never set, therefore we should not read it either.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This mask contains all of the bits that should be ignored while single
stepping in the debugger. The mask contains 2 bits that are not currently
cleared, but are also never set. The bits are included in the mask for
consistency in handling of the CPU_INTERRUPT_TGT_EXT_N bits.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
