From 0585105c806d3bf301eebc33115a0790fcfc1d9c Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 21 Oct 2022 17:34:09 +0100 Subject: Revert "accel/tcg: Init TCG cflags in vCPU thread handler" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit a82fd5a4ec24d was intended to be a code cleanup, but unfortunately it has a bug. It moves the initialization of the TCG cflags from the "start a new vcpu" function to the thread handler; this is fine when each vcpu has its own thread, but when we are doing round-robin of vcpus on a single thread we end up only initializing the cflags for CPU 0, not for any of the others. The most obvious effect of this bug is that running in icount mode with more than one CPU is broken; typically the guest hangs shortly after it brings up the secondary CPUs. This reverts commit a82fd5a4ec24d923ff1e6da128c0fd4a74079d99. Cc: qemu-stable@nongnu.org Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Signed-off-by: Peter Maydell Message-Id: <20221021163409.3674911-1-peter.maydell@linaro.org> Signed-off-by: Richard Henderson --- accel/tcg/tcg-accel-ops-mttcg.c | 5 +++-- accel/tcg/tcg-accel-ops-rr.c | 7 ++++--- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/accel/tcg/tcg-accel-ops-mttcg.c b/accel/tcg/tcg-accel-ops-mttcg.c index ba997f6..d50239e 100644 --- a/accel/tcg/tcg-accel-ops-mttcg.c +++ b/accel/tcg/tcg-accel-ops-mttcg.c @@ -70,8 +70,6 @@ static void *mttcg_cpu_thread_fn(void *arg) assert(tcg_enabled()); g_assert(!icount_enabled()); - tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1); - rcu_register_thread(); force_rcu.notifier.notify = mttcg_force_rcu; force_rcu.cpu = cpu; @@ -141,6 +139,9 @@ void mttcg_start_vcpu_thread(CPUState *cpu) { char thread_name[VCPU_THREAD_NAME_SIZE]; + g_assert(tcg_enabled()); + tcg_cpu_init_cflags(cpu, current_machine->smp.max_cpus > 1); + cpu->thread = g_new0(QemuThread, 1); cpu->halt_cond = g_malloc0(sizeof(QemuCond)); qemu_cond_init(cpu->halt_cond); diff --git a/accel/tcg/tcg-accel-ops-rr.c b/accel/tcg/tcg-accel-ops-rr.c index cc8adc2..1a72149 100644 --- a/accel/tcg/tcg-accel-ops-rr.c +++ b/accel/tcg/tcg-accel-ops-rr.c @@ -152,9 +152,7 @@ static void *rr_cpu_thread_fn(void *arg) Notifier force_rcu; CPUState *cpu = arg; - g_assert(tcg_enabled()); - tcg_cpu_init_cflags(cpu, false); - + assert(tcg_enabled()); rcu_register_thread(); force_rcu.notify = rr_force_rcu; rcu_add_force_rcu_notifier(&force_rcu); @@ -277,6 +275,9 @@ void rr_start_vcpu_thread(CPUState *cpu) static QemuCond *single_tcg_halt_cond; static QemuThread *single_tcg_cpu_thread; + g_assert(tcg_enabled()); + tcg_cpu_init_cflags(cpu, false); + if (!single_tcg_cpu_thread) { cpu->thread = g_new0(QemuThread, 1); cpu->halt_cond = g_new0(QemuCond, 1); -- cgit v1.1