[PULL 10/33] accel: Introduce AccelOpsClass::cpu_thread_is_idle()

["Philippe Mathieu-Daudé" <philippe.mathieu.daude@gmail.com>]

From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Add cpu_thread_is_idle() to AccelOps, and implement it for the
KVM / WHPX accelerators.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220207075426.81934-11-f4bug@amsat.org>
---
 include/sysemu/accel-ops.h        | 1 +
 accel/kvm/kvm-accel-ops.c         | 6 ++++++
 softmmu/cpus.c                    | 6 ++++--
 target/i386/whpx/whpx-accel-ops.c | 6 ++++++
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/sysemu/accel-ops.h b/include/sysemu/accel-ops.h
index 032f6979d76..50c72540c73 100644
--- a/include/sysemu/accel-ops.h
+++ b/include/sysemu/accel-ops.h
@@ -30,6 +30,7 @@ struct AccelOpsClass {
 
     void (*create_vcpu_thread)(CPUState *cpu); /* MANDATORY NON-NULL */
     void (*kick_vcpu_thread)(CPUState *cpu);
+    bool (*cpu_thread_is_idle)(CPUState *cpu);
 
     void (*synchronize_post_reset)(CPUState *cpu);
     void (*synchronize_post_init)(CPUState *cpu);
diff --git a/accel/kvm/kvm-accel-ops.c b/accel/kvm/kvm-accel-ops.c
index 7516c67a3f5..95b7b080202 100644
--- a/accel/kvm/kvm-accel-ops.c
+++ b/accel/kvm/kvm-accel-ops.c
@@ -74,11 +74,17 @@ static void kvm_start_vcpu_thread(CPUState *cpu)
                        cpu, QEMU_THREAD_JOINABLE);
 }
 
+static bool kvm_vcpu_thread_is_idle(CPUState *cpu)
+{
+    return !kvm_halt_in_kernel();
+}
+
 static void kvm_accel_ops_class_init(ObjectClass *oc, void *data)
 {
     AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
 
     ops->create_vcpu_thread = kvm_start_vcpu_thread;
+    ops->cpu_thread_is_idle = kvm_vcpu_thread_is_idle;
     ops->synchronize_post_reset = kvm_cpu_synchronize_post_reset;
     ops->synchronize_post_init = kvm_cpu_synchronize_post_init;
     ops->synchronize_state = kvm_cpu_synchronize_state;
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index ac6bec56038..b17033d3bce 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -90,10 +90,12 @@ bool cpu_thread_is_idle(CPUState *cpu)
     if (cpu_is_stopped(cpu)) {
         return true;
     }
-    if (!cpu->halted || cpu_has_work(cpu) ||
-        kvm_halt_in_kernel() || whpx_apic_in_platform()) {
+    if (!cpu->halted || cpu_has_work(cpu)) {
         return false;
     }
+    if (cpus_accel->cpu_thread_is_idle) {
+        return cpus_accel->cpu_thread_is_idle(cpu);
+    }
     return true;
 }
 
diff --git a/target/i386/whpx/whpx-accel-ops.c b/target/i386/whpx/whpx-accel-ops.c
index 6bc47c53098..1d30e4e2ed2 100644
--- a/target/i386/whpx/whpx-accel-ops.c
+++ b/target/i386/whpx/whpx-accel-ops.c
@@ -83,12 +83,18 @@ static void whpx_kick_vcpu_thread(CPUState *cpu)
     }
 }
 
+static bool whpx_vcpu_thread_is_idle(CPUState *cpu)
+{
+    return !whpx_apic_in_platform();
+}
+
 static void whpx_accel_ops_class_init(ObjectClass *oc, void *data)
 {
     AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
 
     ops->create_vcpu_thread = whpx_start_vcpu_thread;
     ops->kick_vcpu_thread = whpx_kick_vcpu_thread;
+    ops->cpu_thread_is_idle = whpx_vcpu_thread_is_idle;
 
     ops->synchronize_post_reset = whpx_cpu_synchronize_post_reset;
     ops->synchronize_post_init = whpx_cpu_synchronize_post_init;
-- 
2.35.1