Re: [Qemu-devel] [PATCH 10/11] qemu/kvm: kvm hyper-v based guest crash event handling

[Paolo Bonzini]

On 22/06/2015 18:05, Denis V. Lunev wrote:
> +void qemu_system_guest_panicked(void)
> +{
> +    qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_PAUSE, &error_abort);
> +    vm_stop(RUN_STATE_GUEST_PANICKED);
> +}
> +

Please call this in pvpanic.c and target-s390x/kvm.c (replacing the
guest_panicked function in that file there) as well.

> @@ -2540,6 +2573,53 @@ static bool host_supports_vmx(void)
>      return ecx & CPUID_EXT_VMX;
>  }
>  
> +int kvm_arch_handle_hv_crash(CPUState *cs)
> +{
> +    X86CPU *cpu = X86_CPU(cs);
> +    CPUX86State *env = &cpu->env;
> +    struct {
> +        struct kvm_msrs info;
> +        struct kvm_msr_entry entries[HV_X64_MSR_CRASH_PARAMS + 1];
> +    } msr_data;
> +    struct kvm_msr_entry *msrs = msr_data.entries;
> +    int ret, n, i;
> +
> +    if (!has_msr_hv_crash) {
> +        return -EINVAL;
> +    }
> +
> +    for (n = 0; n < HV_X64_MSR_CRASH_PARAMS; n++) {
> +        msrs[n].index = HV_X64_MSR_CRASH_P0 + n;
> +    }
> +
> +    msrs[n++].index = HV_X64_MSR_CRASH_CTL;
> +    msr_data.info = (struct kvm_msrs) {
> +        .nmsrs = n,
> +    };
> +
> +    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    for (i = 0; i < ret; i++) {
> +        uint32_t index = msrs[i].index;
> +
> +        switch (index) {
> +        case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
> +            env->msr_hv_crash_prm[index - HV_X64_MSR_CRASH_P0] = 
> msrs[i].data;
> +            break;
> +        case HV_X64_MSR_CRASH_CTL:
> +            env->msr_hv_crash_ctl = msrs[i].data;
> +            break;
> +        default:
> +            break;
> +        }
> +    }
> +
> +    return 0;
> +}
> +

Is this necessary?  The call to cpu_synchronize_all_states in
qemu_savevm_state_complete should be enough.  If necessary, you can call
it from qemu_system_guest_panicked instead of special casing the crash
MSRs here.

Paolo