[PULL,10/11] target/loongarch: Add kvm steal time feature detection

Commit Message

bibo mao Feb. 25, 2025, noon UTC

Paravirt steal time feature is OnOffAuto type, feature detection is added
to check whether it is supported on KVM host.

Signed-off-by: Bibo Mao <[e-mail]>
Reviewed-by: Bibo Mao <[e-mail]>
---
 target/loongarch/cpu.h     |  1 +
 target/loongarch/kvm/kvm.c | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

Patch

diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index 3e8a91748d..83183a33ab 100644
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -288,6 +288,7 @@  enum loongarch_features {
     LOONGARCH_FEATURE_LBT, /* loongson binary translation extension */
     LOONGARCH_FEATURE_PMU,
     LOONGARCH_FEATURE_PV_IPI,
+    LOONGARCH_FEATURE_STEALTIME,
 };
 
 typedef struct  LoongArchBT {
diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c
index def7451224..59a5f84161 100644
--- a/target/loongarch/kvm/kvm.c
+++ b/target/loongarch/kvm/kvm.c
@@ -924,6 +924,12 @@  static bool kvm_feature_supported(CPUState *cs, enum loongarch_features feature)
         ret = kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
         return (ret == 0);
 
+    case LOONGARCH_FEATURE_STEALTIME:
+        attr.group = KVM_LOONGARCH_VM_FEAT_CTRL;
+        attr.attr = KVM_LOONGARCH_VM_FEAT_PV_STEALTIME;
+        ret = kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        return (ret == 0);
+
     default:
         return false;
     }
@@ -1042,6 +1048,20 @@  static int kvm_cpu_check_pv_features(CPUState *cs, Error **errp)
         env->pv_features |= BIT(KVM_FEATURE_IPI);
     }
 
+    kvm_supported = kvm_feature_supported(cs, LOONGARCH_FEATURE_STEALTIME);
+    if (cpu->kvm_steal_time == ON_OFF_AUTO_ON) {
+        if (!kvm_supported) {
+            error_setg(errp, "'kvm stealtime' feature not supported by KVM host");
+            return -ENOTSUP;
+        }
+    } else if (cpu->kvm_steal_time != ON_OFF_AUTO_AUTO) {
+        kvm_supported = false;
+    }
+
+    if (kvm_supported) {
+        env->pv_features |= BIT(KVM_FEATURE_STEAL_TIME);
+    }
+
     return 0;
 }