[Qemu-arm] [PATCH v4 RFC 2/2] target: arm: Add support for VCPU event states

[Dongjiu Geng]

This patch extends the qemu-kvm state sync logic with support for
KVM_GET/SET_VCPU_EVENTS, giving access to yet missing SError exception.
And also it can support the exception state migration.

Signed-off-by: Dongjiu Geng <address@hidden>
---
change since v3:
1. Add a new new subsection with a suitable 'ras_needed' function
controlling whether it is present
2. Add a ARM_FEATURE_RAS feature bit for CPUARMState

The corresponding kernel patch is here:
https://lkml.org/lkml/2018/6/25/374
---
 target/arm/cpu.h     |  6 ++++++
 target/arm/kvm64.c   | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 target/arm/machine.c | 22 ++++++++++++++++++++
 3 files changed, 87 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 8488273..575c46c 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -645,6 +645,11 @@ typedef struct CPUARMState {
     const struct arm_boot_info *boot_info;
     /* Store GICv3CPUState to access from this struct */
     void *gicv3state;
+    struct {
+        uint32_t pending;
+        uint32_t has_esr;
+        uint64_t esr;
+    } serror;
 } CPUARMState;
 
 /**
@@ -1482,6 +1487,7 @@ enum arm_features {
     ARM_FEATURE_V8_RDM, /* implements v8.1 simd round multiply */
     ARM_FEATURE_V8_FP16, /* implements v8.2 half-precision float */
     ARM_FEATURE_V8_FCMA, /* has complex number part of v8.3 extensions.  */
+    ARM_FEATURE_RAS, /* has RAS Extension */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index e0b8246..660b358 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -527,6 +527,10 @@ int kvm_arch_init_vcpu(CPUState *cs)
         unset_feature(&env->features, ARM_FEATURE_PMU);
     }
 
+    if (kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_INJECT_SERROR_ESR)) {
+        set_feature(&env->features, ARM_FEATURE_RAS);
+    }
+
     /* Do KVM_ARM_VCPU_INIT ioctl */
     ret = kvm_arm_vcpu_init(cs);
     if (ret) {
@@ -600,6 +604,50 @@ int kvm_arm_cpreg_level(uint64_t regidx)
 #define AARCH64_SIMD_CTRL_REG(x)   (KVM_REG_ARM64 | KVM_REG_SIZE_U32 | \
                  KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(x))
 
+static int kvm_put_vcpu_events(ARMCPU *cpu)
+{
+    CPUARMState *env = &cpu->env;
+    struct kvm_vcpu_events events = {};
+
+    if (!kvm_has_vcpu_events()) {
+        return 0;
+    }
+
+    memset(&events, 0, sizeof(events));
+    events.exception.serror_pending = env->serror.pending;
+
+    if (arm_feature(env, ARM_FEATURE_RAS)) {
+        events.exception.serror_has_esr = env->serror.has_esr;
+        events.exception.serror_esr = env->serror.esr;
+    }
+
+    return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_VCPU_EVENTS, &events);
+}
+
+static int kvm_get_vcpu_events(ARMCPU *cpu)
+{
+    CPUARMState *env = &cpu->env;
+    struct kvm_vcpu_events events;
+    int ret;
+
+    if (!kvm_has_vcpu_events()) {
+        return 0;
+    }
+
+    memset(&events, 0, sizeof(events));
+    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_VCPU_EVENTS, &events);
+
+    if (ret < 0) {
+        return ret;
+    }
+
+    env->serror.pending = events.exception.serror_pending;
+    env->serror.has_esr = events.exception.serror_has_esr;
+    env->serror.esr = events.exception.serror_esr;
+
+    return 0;
+}
+
 int kvm_arch_put_registers(CPUState *cs, int level)
 {
     struct kvm_one_reg reg;
@@ -727,6 +775,12 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         return ret;
     }
 
+    ret = kvm_put_vcpu_events(cpu);
+    if (ret) {
+        printf("return error kvm_put_vcpu_events: %d\n", ret);
+        return ret;
+    }
+
     if (!write_list_to_kvmstate(cpu, level)) {
         return EINVAL;
     }
@@ -863,6 +917,11 @@ int kvm_arch_get_registers(CPUState *cs)
     }
     vfp_set_fpcr(env, fpr);
 
+    ret = kvm_get_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     if (!write_kvmstate_to_list(cpu)) {
         return EINVAL;
     }
diff --git a/target/arm/machine.c b/target/arm/machine.c
index 2e28d08..22f2d89 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -172,6 +172,27 @@ static const VMStateDescription vmstate_sve = {
 };
 #endif /* AARCH64 */
 
+static bool ras_needed(void *opaque)
+{
+    ARMCPU *cpu = opaque;
+    CPUARMState *env = &cpu->env;
+
+    return arm_feature(env, ARM_FEATURE_RAS);
+}
+
+static const VMStateDescription vmstate_ras = {
+    .name = "cpu/ras",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = ras_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(env.serror.pending, ARMCPU),
+        VMSTATE_UINT32(env.serror.has_esr, ARMCPU),
+        VMSTATE_UINT64(env.serror.esr, ARMCPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static bool m_needed(void *opaque)
 {
     ARMCPU *cpu = opaque;
@@ -723,6 +744,7 @@ const VMStateDescription vmstate_arm_cpu = {
 #ifdef TARGET_AARCH64
         &vmstate_sve,
 #endif
+        &vmstate_ras,
         NULL
     }
 };
-- 
1.8.3.1