diff mbox series

[PULL,01/47] Revert "accel/tcg: Init TCG cflags in vCPU thread handler"

Message ID 20221026021116.1988449-2-richard.henderson@linaro.org
State Accepted
Commit 0585105c806d3bf301eebc33115a0790fcfc1d9c
Headers show
Series [PULL,01/47] Revert "accel/tcg: Init TCG cflags in vCPU thread handler" | expand

Commit Message

Richard Henderson Oct. 26, 2022, 2:10 a.m. UTC 
From: Peter Maydell <peter.maydell@linaro.org>

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 <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20221021163409.3674911-1-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/tcg-accel-ops-mttcg.c | 5 +++--
 accel/tcg/tcg-accel-ops-rr.c    | 7 ++++---
 2 files changed, 7 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/accel/tcg/tcg-accel-ops-mttcg.c b/accel/tcg/tcg-accel-ops-mttcg.c
index ba997f6cfe..d50239e0e2 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 cc8adc2380..1a72149f0e 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);