Re: [PATCH 3/6] target/arm: Better describe PMU depends on TCG or HVF

[Pierrick Bouvier]

On 6/30/25 6:09 AM, Philippe Mathieu-Daudé wrote:
Simplify PMU logic by rewriting '!KVM' as 'TCG || HVF'
(ignoring QTest, because vCPUs are not available there).
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
  target/arm/cpu.c     |  2 +-
  target/arm/machine.c | 10 +++++-----
  2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index b6a8ba83a46..0311ff315fe 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2352,7 +2352,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error 
**errp)
      if (arm_feature(env, ARM_FEATURE_PMU)) {
          pmu_init(cpu);
  
-        if (!kvm_enabled()) {
+        if (tcg_enabled() || hvf_enabled()) {
              arm_register_pre_el_change_hook(cpu, &pmu_pre_el_change, 0);
              arm_register_el_change_hook(cpu, &pmu_post_el_change, 0);
          }
diff --git a/target/arm/machine.c b/target/arm/machine.c
index e442d485241..baa7ad25ca9 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -1,7 +1,7 @@
  #include "qemu/osdep.h"
  #include "cpu.h"
  #include "qemu/error-report.h"
-#include "system/kvm.h"
+#include "system/hvf.h"
  #include "system/tcg.h"
  #include "kvm_arm.h"
  #include "internals.h"
@@ -853,7 +853,7 @@ static int cpu_pre_save(void *opaque)
  {
      ARMCPU *cpu = opaque;
  
-    if (!kvm_enabled()) {
+    if (tcg_enabled() || hvf_enabled()) {
          pmu_op_start(&cpu->env);
      }
  
@@ -888,7 +888,7 @@ static int cpu_post_save(void *opaque)
  {
      ARMCPU *cpu = opaque;
  
-    if (!kvm_enabled()) {
+    if (tcg_enabled() || hvf_enabled()) {
          pmu_op_finish(&cpu->env);
      }
  
@@ -921,7 +921,7 @@ static int cpu_pre_load(void *opaque)
       */
      env->irq_line_state = UINT32_MAX;
  
-    if (!kvm_enabled()) {
+    if (tcg_enabled() || hvf_enabled()) {
          pmu_op_start(env);
      }
  
@@ -1013,7 +1013,7 @@ static int cpu_post_load(void *opaque, int version_id)
          }
      }
  
-    if (!kvm_enabled()) {
+    if (tcg_enabled() || hvf_enabled()) {
          pmu_op_finish(env);
      }
  

If I understand correctly, this is supported for tcg and hvf, but not 
kvm, right?
I'm just a bit confused by commit description mentioning "simplify 
logic", which is more "make it explicit".

Reviewed-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>

Thanks,
Pierrick