On 4/14/25 03:25, Philippe Mathieu-Daudé wrote:
On 12/4/25 19:24, Pierrick Bouvier wrote:
On 4/11/25 22:30, Nicholas Piggin wrote:
On Fri Apr 11, 2025 at 8:55 AM AEST, Pierrick Bouvier wrote:
On MacOS, UI event loop has to be ran in the main thread of a process.
Because of that restriction, on this platform, qemu main event loop is
ran on another thread [1].
This breaks record/replay feature, which expects thread running
qemu_init
to initialize hold this lock, breaking associated functional tests on
MacOS.
Thus, as a generalization, and similar to how BQL is handled, we release
it after init, and reacquire the lock before entering main event loop,
avoiding a special case if a separate thread is used.
Tested on MacOS with:
$ meson test -C build --setup thorough --print-errorlogs \
func-x86_64-x86_64_replay func-arm-arm_replay func-aarch64-
aarch64_replay
$ ./build/qemu-system-x86_64 -nographic -icount
shift=auto,rr=record,rrfile=replay.log
$ ./build/qemu-system-x86_64 -nographic -icount
shift=auto,rr=replay,rrfile=replay.log
[1] https://gitlab.com/qemu-project/qemu/-/commit/
f5ab12caba4f1656479c1feb5248beac1c833243
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/2907
Signed-off-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
---
system/main.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/system/main.c b/system/main.c
index ecb12fd397c..1c022067349 100644
--- a/system/main.c
+++ b/system/main.c
@@ -25,6 +25,7 @@
#include "qemu/osdep.h"
#include "qemu-main.h"
#include "qemu/main-loop.h"
+#include "system/replay.h"
#include "system/system.h"
#ifdef CONFIG_SDL
@@ -44,10 +45,12 @@ static void *qemu_default_main(void *opaque)
{
int status;
+ replay_mutex_lock();
bql_lock();
status = qemu_main_loop();
qemu_cleanup(status);
bql_unlock();
+ replay_mutex_unlock();
exit(status);
}
@@ -67,6 +70,7 @@ int main(int argc, char **argv)
{
qemu_init(argc, argv);
bql_unlock();
+ replay_mutex_unlock();
if (qemu_main) {
QemuThread main_loop_thread;
qemu_thread_create(&main_loop_thread, "qemu_main",
Do we actually need to hold replay mutex (or even bql) over qemu_init()?
Both should get dropped before we return here. But as a simple fix, I
guess this is okay.
For the bql, I don't know the exact reason.
For replay lock, we need to hold it as clock gets saved as soon as the
devices are initialized, which happens before end of qemu_init.
Could be worth adding a comment with that information.
In case someone is curious about it, changing default state of lock can
answer why it's needed, as it crashes immediately on an assert.
Reviewed-by: Nicholas Piggin <npig...@gmail.com>
