On Wed, 2025-01-08 at 15:56 +0000, Alex Bennée wrote: > Ilya Leoshkevich <[email protected]> writes: > > > Hi, > > > > On reporting a breakpoint in a non-non-stop mode, GDB remotes must > > stop > > all threads. Currently qemu-user doesn't do that, breaking the > > debugging session for at least two reasons: concurrent access to > > the > > GDB socket, and an assertion within GDB [1]. > > > > This series fixes this by importing pause_all_vcpus() from qemu- > > system. > > This in turn requires introducing BQL and a few stubs to qemu-user. > > Is there a conclusion to this design choice? I'd like to avoid > bringing > in a bunch of system-mode infrastructure if the existing exclusive > code > would work. For that I'll defer to the linux-user maintainer or > Richard > who knows the code better than I do.
I wanted to re-implement parking CPUs using a reserved host signal. I've submitted the foundations for this in [1], and I'm currently waiting for the review. [1] https://lore.kernel.org/qemu-devel/[email protected]/ > > I could certainly harvest the early clean-up patches to keep the > delta > low while the details are worked out. Is there going to be a v2? It would be great if clean-up patches could be taken separately, since IMHO they make sense on their own. I plan to send a v2 after [1] is integrated. > > Best regards, > > Ilya > > > > [1] https://gitlab.com/qemu-project/qemu/-/issues/2465 > > > > Ilya Leoshkevich (18): > > gdbstub: Make gdb_get_char() static > > gdbstub: Move phy_memory_mode to GDBSystemState > > gdbstub: Move gdb_syscall_mode to GDBSyscallState > > gdbstub: Factor out gdb_try_stop() > > accel/tcg: Factor out cpu_exec_user() > > qemu-thread: Introduce QEMU_MUTEX_INITIALIZER > > qemu-thread: Introduce QEMU_COND_INITIALIZER > > replay: Add replay_mutex_{lock,unlock}() stubs for qemu-user > > qemu-timer: Provide qemu_clock_enable() stub for qemu-user > > cpu: Use BQL in qemu-user > > accel/tcg: Unify user implementations of qemu_cpu_kick() > > cpu: Track CPUs executing syscalls > > cpu: Implement cpu_thread_is_idle() for qemu-user > > cpu: Introduce cpu_is_paused() > > cpu: Set current_cpu early in qemu-user > > cpu: Allow pausing and resuming CPUs in qemu-user > > gdbstub: Pause all CPUs before sending stop replies > > tests/tcg: Stress test thread breakpoints > > > > accel/tcg/user-exec-stub.c | 4 - > > accel/tcg/user-exec.c | 55 ++++++ > > bsd-user/aarch64/target_arch_cpu.h | 6 +- > > bsd-user/arm/target_arch_cpu.h | 5 +- > > bsd-user/freebsd/os-syscall.c | 10 + > > bsd-user/i386/target_arch_cpu.h | 5 +- > > bsd-user/main.c | 8 +- > > bsd-user/x86_64/target_arch_cpu.h | 5 +- > > cpu-common.c | 179 > > ++++++++++++++++++ > > gdbstub/gdbstub.c | 17 +- > > gdbstub/internals.h | 4 +- > > gdbstub/syscalls.c | 20 +- > > gdbstub/system.c | 18 +- > > gdbstub/user.c | 28 ++- > > include/exec/cpu-common.h | 15 ++ > > include/exec/replay-core.h | 13 ++ > > include/hw/core/cpu.h | 1 + > > include/qemu/thread-posix.h | 8 + > > include/qemu/thread-win32.h | 8 + > > include/sysemu/cpus.h | 6 - > > include/sysemu/replay.h | 13 -- > > linux-user/aarch64/cpu_loop.c | 5 +- > > linux-user/alpha/cpu_loop.c | 5 +- > > linux-user/arm/cpu_loop.c | 5 +- > > linux-user/hexagon/cpu_loop.c | 5 +- > > linux-user/hppa/cpu_loop.c | 5 +- > > linux-user/i386/cpu_loop.c | 5 +- > > linux-user/loongarch64/cpu_loop.c | 5 +- > > linux-user/m68k/cpu_loop.c | 5 +- > > linux-user/main.c | 9 +- > > linux-user/microblaze/cpu_loop.c | 5 +- > > linux-user/mips/cpu_loop.c | 5 +- > > linux-user/openrisc/cpu_loop.c | 5 +- > > linux-user/ppc/cpu_loop.c | 5 +- > > linux-user/riscv/cpu_loop.c | 5 +- > > linux-user/s390x/cpu_loop.c | 5 +- > > linux-user/sh4/cpu_loop.c | 5 +- > > linux-user/sparc/cpu_loop.c | 5 +- > > linux-user/syscall.c | 12 ++ > > linux-user/xtensa/cpu_loop.c | 5 +- > > replay/stubs-system.c | 8 + > > stubs/meson.build | 8 + > > stubs/qemu-timer.c | 6 + > > stubs/replay-mutex.c | 10 + > > stubs/replay-tools.c | 8 - > > system/cpus.c | 172 +------------- > > --- > > tests/tcg/multiarch/Makefile.target | 13 +- > > .../gdbstub/test-thread-breakpoint-stress.py | 28 +++ > > .../tcg/multiarch/thread-breakpoint-stress.c | 92 +++++++++ > > 49 files changed, 552 insertions(+), 327 deletions(-) > > create mode 100644 stubs/qemu-timer.c > > create mode 100644 stubs/replay-mutex.c > > create mode 100644 tests/tcg/multiarch/gdbstub/test-thread- > > breakpoint-stress.py > > create mode 100644 tests/tcg/multiarch/thread-breakpoint-stress.c >
