Re: [PATCH v5 05/31] sysemu: Introduce AccelOpsClass::has_work()

[Philippe Mathieu-Daudé]

On 9/20/21 23:58, Richard Henderson wrote:

On 9/20/21 2:44 PM, Philippe Mathieu-Daudé wrote:

-    g_assert(cc->has_work);
-    return cc->has_work(cpu);
+    if (cc->has_work) {
+    return cc->has_work(cpu);
+    }
+    if (cpus_accel->has_work) {
+    return cpus_accel->has_work(cpu);
+    }
+    g_assert_not_reached();


This might be close to the end result, but it isn't what we begin with 
in cpu_thread_is_idle.


You'd want

     if (cc->has_work && cc->has_work(cpu)) {
     return true;
     }
     if (cpus_accel->has_work && cpus_accel->has_work(cpu)) {
     return true;
     }
     return false;

to start.  After the cpus_accel hook is filled in you can assert and 
return from cpus_accel->has_work.  And of course after cc->has_work is 
removed, that clause is gone.


Much cleaner, thank you for the hints :)

Re: [PATCH v5 05/31] sysemu: Introduce AccelOpsClass::has_work()

[Richard Henderson]

On 9/20/21 2:44 PM, Philippe Mathieu-Daudé wrote:

-g_assert(cc->has_work);
-return cc->has_work(cpu);
+if (cc->has_work) {
+return cc->has_work(cpu);
+}
+if (cpus_accel->has_work) {
+return cpus_accel->has_work(cpu);
+}
+g_assert_not_reached();


This might be close to the end result, but it isn't what we begin with in 
cpu_thread_is_idle.

You'd want

if (cc->has_work && cc->has_work(cpu)) {
return true;
}
if (cpus_accel->has_work && cpus_accel->has_work(cpu)) {
return true;
}
return false;

to start.  After the cpus_accel hook is filled in you can assert and return from 
cpus_accel->has_work.  And of course after cc->has_work is removed, that clause is gone.



r~

[PATCH v5 05/31] sysemu: Introduce AccelOpsClass::has_work()

[Philippe Mathieu-Daudé]

Introduce an accelerator-specific has_work() handler.
Eventually call it from cpu_has_work().

Signed-off-by: Philippe Mathieu-Daudé 
---
 include/sysemu/accel-ops.h | 5 +
 softmmu/cpus.c | 9 +++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/sysemu/accel-ops.h b/include/sysemu/accel-ops.h
index 032f6979d76..de83f095f20 100644
--- a/include/sysemu/accel-ops.h
+++ b/include/sysemu/accel-ops.h
@@ -31,6 +31,11 @@ struct AccelOpsClass {
 void (*create_vcpu_thread)(CPUState *cpu); /* MANDATORY NON-NULL */
 void (*kick_vcpu_thread)(CPUState *cpu);
 
+/**
+ * @has_work: Callback for checking if there is work to do.
+ */
+bool (*has_work)(CPUState *cpu);
+
 void (*synchronize_post_reset)(CPUState *cpu);
 void (*synchronize_post_init)(CPUState *cpu);
 void (*synchronize_state)(CPUState *cpu);
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index 7e2cb2c571b..e59046ce39c 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -255,8 +255,13 @@ bool cpu_has_work(CPUState *cpu)
 {
 CPUClass *cc = CPU_GET_CLASS(cpu);
 
-g_assert(cc->has_work);
-return cc->has_work(cpu);
+if (cc->has_work) {
+return cc->has_work(cpu);
+}
+if (cpus_accel->has_work) {
+return cpus_accel->has_work(cpu);
+}
+g_assert_not_reached();
 }
 
 static int do_vm_stop(RunState state, bool send_stop)
-- 
2.31.1