The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().
The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.
The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)
There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Since commit fa92bd4af7 ("target/xtensa: fix access to
the INTERRUPT SR") these files use QEMU atomic API.
Explicit the header inclusion instead of relying on
implicit and indirect inclusion.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230828221314.18435-10-philmd@linaro.org>
In handle_interrupt() we use level as an index into the interrupt_vector[]
array. This is safe because we have checked it against env->config->nlevel,
but Coverity can't see that (and it is only true because each CPU config
sets its XCHAL_NUM_INTLEVELS to something less than MAX_NLEVELS), so it
complains about a possible array overrun (CID 1507131)
Add an assert() which will make Coverity happy and catch the unlikely
case of a mis-set XCHAL_NUM_INTLEVELS in future.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Message-id: 20230623154135.1930261-1-peter.maydell@linaro.org
Many files use "qemu/log.h" declarations but neglect to include
it (they inherit it via "exec/exec-all.h"). "exec/exec-all.h" is
a core component and shouldn't be used that way. Move the
"qemu/log.h" inclusion locally to each unit requiring it.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20220207082756.82600-10-f4bug@amsat.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Restrict cpu_exec_interrupt() and its callees to sysemu.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210911165434.531552-23-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
target/xtensa used to generate an extra EXCP_DEBUG exception before the
first instruction executed after an interrupt or an exception is taken
to allow single-stepping that instruction in the debugger.
This is no longer needed after the following commits:
a7ba744f40 ("tcg/cpu-exec: precise single-stepping after an exception")
ba3c35d9c4 ("tcg/cpu-exec: precise single-stepping after an interrupt")
Drop exception state tracking/extra EXCP_DEBUG generation code.
Cc: qemu-stable@nongnu.org # v5.1, v5.2, v6.0
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:
$ CC=clang CXX=clang++ ./configure ... && make
../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.
This patch was generated using:
$ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
sort -u >/tmp/changed_identifiers
$ for identifier in $(</tmp/changed_identifiers); do
sed -i "s%\<$identifier\>%q$identifier%g" \
$(git grep -I -l "\<$identifier\>")
done
I manually fixed line-wrap issues and misaligned rST tables.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
When NMI is configured it is taken regardless of INTENABLE SR contents,
PS.INTLEVEL or PS.EXCM. It is cleared automatically once it's taken.
Add nmi_level to XtensaConfig, puth there NMI level from the overlay or
XCHAL_NUM_INTLEVELS + 1 when NMI is not configured. Add NMI mask to
INTENABLE SR and limit CINTLEVEL to nmi_level - 1 when determining
pending IRQ level in check_interrupt(). Always take and clear pending
interrupt at nmi_level in the handle_interrupt().
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Cleanup in the boilerplate that each target must define.
Replace xtensa_env_get_cpu with env_archcpu. The combination
CPU(xtensa_env_get_cpu) should have used ENV_GET_CPU to begin;
use env_cpu now.
Move cpu_get_tb_cpu_state below the include of "exec/cpu-all.h"
so that the definition of env_cpu is available.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
INTERRUPT special register may be changed both by the core (by writing
to INTSET and INTCLEAR registers) and by external events (by triggering
and clearing HW IRQs). In MTTCG this state must be protected from
concurrent access, otherwise interrupts may be lost or spurious
interrupts may be detected.
Use atomic operations to change INTSET SR.
Fix wsr.intset so that it soesn't clear any bits.
Fix wsr.intclear so that it doesn't clear bit that corresponds to NMI.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Move helper functions related to interrupt and exception handling from
op_helper.c and helper.c to exc_helper.c. No functional changes.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
