[PATCH 12/18] cpu: Track CPUs executing syscalls

[Ilya Leoshkevich <iii@linux.ibm.com>]

CPUs that execute syscalls should be considered paused by
all_vcpus_paused(). Lay the groundwork by introducing a bool field in
CPUState to track this. The field is not used by sysemu, but it's only
one byte, so it should not be a problem.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 accel/tcg/user-exec.c         | 10 ++++++++++
 bsd-user/freebsd/os-syscall.c |  4 ++++
 include/exec/cpu-common.h     |  2 ++
 include/hw/core/cpu.h         |  1 +
 linux-user/syscall.c          |  5 +++++
 5 files changed, 22 insertions(+)

diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 7bd6e94b8e8..3ebace1e833 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -1307,3 +1307,13 @@ void qemu_cpu_kick(CPUState *cpu)
 {
     cpu_exit(cpu);
 }
+
+void cpu_enter_syscall(CPUState *cs)
+{
+    cs->in_syscall = true;
+}
+
+void cpu_exit_syscall(CPUState *cs)
+{
+    cs->in_syscall = false;
+}
diff --git a/bsd-user/freebsd/os-syscall.c b/bsd-user/freebsd/os-syscall.c
index c2849d43223..9f54345e11b 100644
--- a/bsd-user/freebsd/os-syscall.c
+++ b/bsd-user/freebsd/os-syscall.c
@@ -936,6 +936,8 @@ abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
 {
     abi_long ret;
 
+    cpu_enter_syscall(env_cpu(cpu_env));
+
     bql_unlock();
 
     if (do_strace) {
@@ -951,6 +953,8 @@ abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
 
     bql_lock();
 
+    cpu_exit_syscall(env_cpu(cpu_env));
+
     return ret;
 }
 
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 4a7b43f9aa3..32bd3cad83f 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -228,6 +228,8 @@ G_NORETURN void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc);
 int cpu_exec(CPUState *cpu);
 /* accel/tcg/user-exec.c */
 int cpu_exec_user(CPUState *cs);
+void cpu_enter_syscall(CPUState *cs);
+void cpu_exit_syscall(CPUState *cs);
 
 /**
  * env_archcpu(env)
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 1c9c775df65..d073a79731b 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -475,6 +475,7 @@ struct CPUState {
     bool created;
     bool stop;
     bool stopped;
+    bool in_syscall;
 
     /* Should CPU start in powered-off state? */
     bool start_powered_off;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ff34ae11340..344c2e65234 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -13771,6 +13771,8 @@ abi_long do_syscall(CPUArchState *cpu_env, int num, abi_long arg1,
     }
 #endif
 
+    cpu_enter_syscall(cpu);
+
     record_syscall_start(cpu, num, arg1,
                          arg2, arg3, arg4, arg5, arg6, arg7, arg8);
 
@@ -13791,5 +13793,8 @@ abi_long do_syscall(CPUArchState *cpu_env, int num, abi_long arg1,
     bql_lock();
 
     record_syscall_return(cpu, num, ret);
+
+    cpu_exit_syscall(cpu);
+
     return ret;
 }
-- 
2.46.0