On 9/25/21 17:32, Richard Henderson wrote:
On 9/25/21 11:27 AM, Philippe Mathieu-Daudé wrote:
+static bool qtest_cpu_has_work(CPUState *cpu)
+{
+ g_assert_not_reached();
+}
Sigh, this triggers:
Running test qtest-i386/cpu-plug-test
**
ERROR:../accel/qtest/qtest.c:52:qtest_cpu_has_work: code should not be
reached
ERROR qtest-i386/cpu-plug-test - Bail out!
ERROR:../accel/qtest/qtest.c:52:qtest_cpu_has_work: code should not be
reached
Broken pipe
Ha ha, yes. You beat me to the reply within minutes.
I suppose it is in my interest to 'return false' here and call it
a day...
I *think* that's the right thing, but I could see maybe "true" also
makes sense. I'll try and have a closer look.
So first I tested using "-machine pc,accel=qtest" -> no crash.
Looking closely at how check-qtest calls QEMU, it does:
"-machine pc -accel qtest". Isn't the sugar property supposed
to work that way?
Then the backtrace is:
Thread 5 "qemu-system-i38" hit Breakpoint 1, qtest_cpu_has_work
(cpu=0x555556a08400) at accel/qtest/qtest.c:52
52 g_assert_not_reached();
(gdb) bt
#0 qtest_cpu_has_work (cpu=0x555556a08400) at accel/qtest/qtest.c:52
#1 0x0000555555c330ba in cpu_has_work (cpu=0x555556a08400) at
softmmu/cpus.c:254
#2 0x0000555555c32ac8 in cpu_thread_is_idle (cpu=0x555556a08400) at
softmmu/cpus.c:91
#3 0x0000555555c33584 in qemu_wait_io_event (cpu=0x555556a08400) at
softmmu/cpus.c:417
#4 0x0000555555d8a7f4 in dummy_cpu_thread_fn (arg=0x555556a08400) at
accel/dummy-cpus.c:53
#5 0x0000555555f469f6 in qemu_thread_start (args=0x5555574edae0) at
util/qemu-thread-posix.c:557
#6 0x00007ffff4ff3299 in start_thread () at /lib64/libpthread.so.0
#7 0x00007ffff4f1b353 in clone () at /lib64/libc.so.6
dummy_cpu_thread_fn() content didn't change since its introduction
in commit c7f0f3b1c82 ("qtest: add test framework"):
"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."
Based on that description, qtest should provide a command to notify
whether the CPU has work to do or not.
Meanwhile, no qtest command = no work = 'return false'.
