[v2,4/8] target/loongarch: Add paravirt ipi feature detection

Commit Message

Bibo Mao Feb. 24, 2025, 3:27 a.m. UTC

Paravirt ipi feature is OnOffAuto type, feature detection is added
to check whether it is supported by KVM host.

Signed-off-by: Bibo Mao <[e-mail]>
---
 target/loongarch/cpu.h     |  2 ++
 target/loongarch/kvm/kvm.c | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

Patch

diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index a9466f34b0..5eae17fcbd 100644
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -287,6 +287,7 @@  enum loongarch_features {
     LOONGARCH_FEATURE_LASX,
     LOONGARCH_FEATURE_LBT, /* loongson binary translation extension */
     LOONGARCH_FEATURE_PMU,
+    LOONGARCH_FEATURE_PV_IPI,
 };
 
 typedef struct  LoongArchBT {
@@ -310,6 +311,7 @@  typedef struct CPUArchState {
     lbt_t  lbt;
 
     uint32_t cpucfg[21];
+    uint32_t pv_features;
 
     /* LoongArch CSRs */
     uint64_t CSR_CRMD;
diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c
index 52d574150f..7774a3b870 100644
--- a/target/loongarch/kvm/kvm.c
+++ b/target/loongarch/kvm/kvm.c
@@ -8,7 +8,7 @@ 
 #include "qemu/osdep.h"
 #include <sys/ioctl.h>
 #include <linux/kvm.h>
-
+#include "asm-loongarch/kvm_para.h"
 #include "qapi/error.h"
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
@@ -875,6 +875,12 @@  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_PV_IPI:
+        attr.group = KVM_LOONGARCH_VM_FEAT_CTRL;
+        attr.attr = KVM_LOONGARCH_VM_FEAT_PV_IPI;
+        ret = kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        return (ret == 0);
+
     default:
         return false;
     }
@@ -973,6 +979,29 @@  static int kvm_cpu_check_pmu(CPUState *cs, Error **errp)
     return 0;
 }
 
+static int kvm_cpu_check_pv_features(CPUState *cs, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(cs);
+    CPULoongArchState *env = cpu_env(cs);
+    bool kvm_supported;
+
+    kvm_supported = kvm_feature_supported(cs, LOONGARCH_FEATURE_PV_IPI);
+    if (cpu->kvm_pv_ipi == ON_OFF_AUTO_ON) {
+        if (!kvm_supported) {
+            error_setg(errp, "'pv_ipi' feature not supported by KVM host");
+            return -ENOTSUP;
+        }
+    } else if (cpu->kvm_pv_ipi != ON_OFF_AUTO_AUTO) {
+        kvm_supported = false;
+    }
+
+    if (kvm_supported) {
+        env->pv_features |= BIT(KVM_FEATURE_IPI);
+    }
+
+    return 0;
+}
+
 int kvm_arch_init_vcpu(CPUState *cs)
 {
     uint64_t val;
@@ -1006,6 +1035,11 @@  int kvm_arch_init_vcpu(CPUState *cs)
         error_report_err(local_err);
     }
 
+    ret = kvm_cpu_check_pv_features(cs, &local_err);
+    if (ret < 0) {
+        error_report_err(local_err);
+    }
+
     return ret;
 }